taxonID	type	format	identifier	references	title	description	created	creator	contributor	publisher	audience	source	license	rightsHolder	datasetID
5F0F3852FFA8FFF5FDB5FDBBFB3E2B68.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258856/files/figure.png	https://doi.org/10.5281/zenodo.7258856	Fig. 2. Maximum likelihood (ML) tree for the palaeonemertean supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Numbers beside nodes indicate support values. Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to the new species Tubulanus cf. lutescens are highlighted in bold. When available a specimen-ID, sampling locality, and depth (for deep-sea species) are provided. A statistical parsimony haplotype network based on the COI gene fragment reveals close relationship between Tubulanus cf. lutescens and Tubulanus lutescens.	Fig. 2. Maximum likelihood (ML) tree for the palaeonemertean supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Numbers beside nodes indicate support values. Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to the new species Tubulanus cf. lutescens are highlighted in bold. When available a specimen-ID, sampling locality, and depth (for deep-sea species) are provided. A statistical parsimony haplotype network based on the COI gene fragment reveals close relationship between Tubulanus cf. lutescens and Tubulanus lutescens.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFA8FFF1FDC3FC8EFD2A2912.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258860/files/figure.png	https://doi.org/10.5281/zenodo.7258860	Fig. 3. Live images of palaeonemerteans, heteronemerteans, and polystiliferous hoplonemerteans collected along the Costa Rica margin. A. Tubulanus cf. lutescens (SIO-BIC N107) (Palaeonemertea). B. Dorsal surface of head region of Tubulanus cf. lutescens (SIO-BIC N233). C. Lineidae (SIO-BIC N254) (Heteronemertea). D–E. Reptantia (SIO-BIC N263) (Polystilifera) dorsal (D) and ventral view (E).	Fig. 3. Live images of palaeonemerteans, heteronemerteans, and polystiliferous hoplonemerteans collected along the Costa Rica margin. A. Tubulanus cf. lutescens (SIO-BIC N107) (Palaeonemertea). B. Dorsal surface of head region of Tubulanus cf. lutescens (SIO-BIC N233). C. Lineidae (SIO-BIC N254) (Heteronemertea). D–E. Reptantia (SIO-BIC N263) (Polystilifera) dorsal (D) and ventral view (E).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFA8FFF1FDC3FC8EFD2A2912.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258862/files/figure.png	https://doi.org/10.5281/zenodo.7258862	Fig. 4. Tubulanus cf. lutescens Cantell, 2001 (SIO-BIC N277), transverse histological sections. A. Anterior region of head with proboscis pore. B. Posterior brain region with mouth opening and buccal nerves (arrowheads). C. Proboscis composition and the two proboscis nerves (arrowheads) in the foregut region. D. Brain region showing the cerebral canal. E. Body wall composition in the foregut region, arrowhead indicates upper dorsal nerve. F. Lateral nerve cord in the foregut region. Abbreviations: br = brain; cc = cerebral canal; cl = cephalic loop; dl = dorsal brain lobe; e = epidermis; es = esophagus; icm = inner circular muscle layer; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mo = mouth opening; ocm = outer circular muscle layer; p = proboscis; pcm = circular musculature of proboscis; pcn = precerebral nerves; pe = proboscis epithelium; plm = longitudinal musculature of proboscis; pp = proboscis pore; rc = rhynchocoel; rcm = circular musculature of rhynchocoel; vc = ventral commissure; vl = ventral brain lobe. Scale bars: A–C, E = 200 µm; D, F = 100 µm.	Fig. 4. Tubulanus cf. lutescens Cantell, 2001 (SIO-BIC N277), transverse histological sections. A. Anterior region of head with proboscis pore. B. Posterior brain region with mouth opening and buccal nerves (arrowheads). C. Proboscis composition and the two proboscis nerves (arrowheads) in the foregut region. D. Brain region showing the cerebral canal. E. Body wall composition in the foregut region, arrowhead indicates upper dorsal nerve. F. Lateral nerve cord in the foregut region. Abbreviations: br = brain; cc = cerebral canal; cl = cephalic loop; dl = dorsal brain lobe; e = epidermis; es = esophagus; icm = inner circular muscle layer; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mo = mouth opening; ocm = outer circular muscle layer; p = proboscis; pcm = circular musculature of proboscis; pcn = precerebral nerves; pe = proboscis epithelium; plm = longitudinal musculature of proboscis; pp = proboscis pore; rc = rhynchocoel; rcm = circular musculature of rhynchocoel; vc = ventral commissure; vl = ventral brain lobe. Scale bars: A–C, E = 200 µm; D, F = 100 µm.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFACFFF0FDC5FE64FE7829F7.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258860/files/figure.png	https://doi.org/10.5281/zenodo.7258860	Fig. 3. Live images of palaeonemerteans, heteronemerteans, and polystiliferous hoplonemerteans collected along the Costa Rica margin. A. Tubulanus cf. lutescens (SIO-BIC N107) (Palaeonemertea). B. Dorsal surface of head region of Tubulanus cf. lutescens (SIO-BIC N233). C. Lineidae (SIO-BIC N254) (Heteronemertea). D–E. Reptantia (SIO-BIC N263) (Polystilifera) dorsal (D) and ventral view (E).	Fig. 3. Live images of palaeonemerteans, heteronemerteans, and polystiliferous hoplonemerteans collected along the Costa Rica margin. A. Tubulanus cf. lutescens (SIO-BIC N107) (Palaeonemertea). B. Dorsal surface of head region of Tubulanus cf. lutescens (SIO-BIC N233). C. Lineidae (SIO-BIC N254) (Heteronemertea). D–E. Reptantia (SIO-BIC N263) (Polystilifera) dorsal (D) and ventral view (E).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFACFFF0FDC5FE64FE7829F7.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258864/files/figure.png	https://doi.org/10.5281/zenodo.7258864	Fig. 5. Maximum likelihood (ML) tree for the heteronemertean supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Numbers beside nodes indicate support values. Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Tubulanus polymorphus Renier, 1804 and Carinoma mutabilis Griffin, 1898 were used for outgroup rooting. The specimen found at the Costa Rica margin is given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 5. Maximum likelihood (ML) tree for the heteronemertean supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Numbers beside nodes indicate support values. Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Tubulanus polymorphus Renier, 1804 and Carinoma mutabilis Griffin, 1898 were used for outgroup rooting. The specimen found at the Costa Rica margin is given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFADFFF0FDF5FC78FB452DAB.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFADFFF0FDF5FC78FB452DAB.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFADFFF0FDC5FE00FAD22B5E.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258860/files/figure.png	https://doi.org/10.5281/zenodo.7258860	Fig. 3. Live images of palaeonemerteans, heteronemerteans, and polystiliferous hoplonemerteans collected along the Costa Rica margin. A. Tubulanus cf. lutescens (SIO-BIC N107) (Palaeonemertea). B. Dorsal surface of head region of Tubulanus cf. lutescens (SIO-BIC N233). C. Lineidae (SIO-BIC N254) (Heteronemertea). D–E. Reptantia (SIO-BIC N263) (Polystilifera) dorsal (D) and ventral view (E).	Fig. 3. Live images of palaeonemerteans, heteronemerteans, and polystiliferous hoplonemerteans collected along the Costa Rica margin. A. Tubulanus cf. lutescens (SIO-BIC N107) (Palaeonemertea). B. Dorsal surface of head region of Tubulanus cf. lutescens (SIO-BIC N233). C. Lineidae (SIO-BIC N254) (Heteronemertea). D–E. Reptantia (SIO-BIC N263) (Polystilifera) dorsal (D) and ventral view (E).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFADFFF0FDC5FE00FAD22B5E.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258866/files/figure.png	https://doi.org/10.5281/zenodo.7258866	Fig. 6. Maximum likelihood (ML) tree for the polystiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. The reptant hoplonemertean specimen collected at the Costa Rica margin is given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 6. Maximum likelihood (ML) tree for the polystiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. The reptant hoplonemertean specimen collected at the Costa Rica margin is given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFADFFEEFD9EF9CCFC2A2C6D.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB3FFEBFDEDFBC9FE132D3A.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258854/files/figure.png	https://doi.org/10.5281/zenodo.7258854	Fig. 1. Sampling sites along the Costa Rica margin and exemplary habitat pictures. A. Map of the seven sampling sites along the Costa Rica margin: Cocos Canyon (CC), Jaco Scar (JS), Mound 11 (M11), Mound 12 (M12), Mound Jaguar (MJ), Parrita Seep (PS), and Quepos Plateau (QP). B. Aggregation of the vestamentiferan Escarpia spicata Jones, 1985. C. Nemerteans of the species Chernyshevia escarpiaphila sp. nov. (arrows) found on Escarpia spicata. Photo credit: ROV SuBastian/Schmidt Ocean Institute.	Fig. 1. Sampling sites along the Costa Rica margin and exemplary habitat pictures. A. Map of the seven sampling sites along the Costa Rica margin: Cocos Canyon (CC), Jaco Scar (JS), Mound 11 (M11), Mound 12 (M12), Mound Jaguar (MJ), Parrita Seep (PS), and Quepos Plateau (QP). B. Aggregation of the vestamentiferan Escarpia spicata Jones, 1985. C. Nemerteans of the species Chernyshevia escarpiaphila sp. nov. (arrows) found on Escarpia spicata. Photo credit: ROV SuBastian/Schmidt Ocean Institute.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB3FFEBFDEDFBC9FE132D3A.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB3FFEBFDEDFBC9FE132D3A.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258874/files/figure.png	https://doi.org/10.5281/zenodo.7258874	Fig. 9. Chernyshevia escarpiaphila gen. et sp. nov. A–C. Paratype (MZUCR Nemertea Collection MZUCR-104-01), transverse histological sections. D–G. Holotype (SIO-BIC N279), histological sections. A. Anterior tip of head with proboscis pore. B. Region anterior to cerebral ganglia with wellvisible cephalic glands. C. Brain region depicting ventral commissure. D. Longitudinal section through brain region showing the cerebral canal (arrowheads). E. Lateral nerve cord with accessory nerve in the stomach region. F. Rhynchocoel in stomach region with well-visible mid-dorsal vessel. G. Intestinal region with testes. Abbreviations: an = accessory nerve; br = brain; cg = cephalic gland; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; es = esophagus; i = intestine; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal vessel; p = proboscis; pcn = precerebral nerves; pp = proboscis pore; rc = rhynchocoel; st = stomach; t = testis; vc = ventral commissure; vl = ventral brain lobe. Scale bars = 100 µm.	Fig. 9. Chernyshevia escarpiaphila gen. et sp. nov. A–C. Paratype (MZUCR Nemertea Collection MZUCR-104-01), transverse histological sections. D–G. Holotype (SIO-BIC N279), histological sections. A. Anterior tip of head with proboscis pore. B. Region anterior to cerebral ganglia with wellvisible cephalic glands. C. Brain region depicting ventral commissure. D. Longitudinal section through brain region showing the cerebral canal (arrowheads). E. Lateral nerve cord with accessory nerve in the stomach region. F. Rhynchocoel in stomach region with well-visible mid-dorsal vessel. G. Intestinal region with testes. Abbreviations: an = accessory nerve; br = brain; cg = cephalic gland; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; es = esophagus; i = intestine; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal vessel; p = proboscis; pcn = precerebral nerves; pp = proboscis pore; rc = rhynchocoel; st = stomach; t = testis; vc = ventral commissure; vl = ventral brain lobe. Scale bars = 100 µm.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB3FFEBFDEDFBC9FE132D3A.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB6FFEAFDA2FA9DFEFB2B53.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB7FFE8FDCDFCBBFBEA2D48.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB7FFE8FDCDFCBBFBEA2D48.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258876/files/figure.png	https://doi.org/10.5281/zenodo.7258876	Fig. 10. A–G. Alvinonemertes dariae gen. et sp. nov., holotype (SIO-BIC N281), transverse histological sections. H–N. Alvinonemertes claudiae gen. et sp. nov., holotype (SIO-BIC N283), transverse histological sections. A. Anterior tip of head with proboscis pore. B. Brain region. C. Anterior brain region with cerebral canal (arrowhead). D. Stomach region with excretory canal. E. Posterior body region with testes. F. Lateral nerve cord with accessory nerve in stomach region. G. Proboscis armature, accessory stylet pouches with accessory stylets. H. Anterior tip of head with proboscis pore. I. Region anterior to cerebral ganglia with well-visible cerebral canal (arrowhead). J. Anterior brain region. K. Pyloric region. L. Proboscis and mid-dorsal vessel in stomach region. M. Proboscis armature, circular basis of central stylet. N. Proboscis armature, accessory stylet pouches with accessory stylets. Abbreviations: an = accessory nerve; ap = accessory stylet pouch; as = accessory stylet; bl = blood vessel; br = brain; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; gd = gonoduct; i = intestine; ic = intestinal cecum; ip = intestinal pouches; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal vessel; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; rd = rhynchodaeum; sb = stylet basis; st = stomach; t = testis; vl = ventral brain lobe. Scale bars: A–G = 100 µm; H–N = 30 µm.	Fig. 10. A–G. Alvinonemertes dariae gen. et sp. nov., holotype (SIO-BIC N281), transverse histological sections. H–N. Alvinonemertes claudiae gen. et sp. nov., holotype (SIO-BIC N283), transverse histological sections. A. Anterior tip of head with proboscis pore. B. Brain region. C. Anterior brain region with cerebral canal (arrowhead). D. Stomach region with excretory canal. E. Posterior body region with testes. F. Lateral nerve cord with accessory nerve in stomach region. G. Proboscis armature, accessory stylet pouches with accessory stylets. H. Anterior tip of head with proboscis pore. I. Region anterior to cerebral ganglia with well-visible cerebral canal (arrowhead). J. Anterior brain region. K. Pyloric region. L. Proboscis and mid-dorsal vessel in stomach region. M. Proboscis armature, circular basis of central stylet. N. Proboscis armature, accessory stylet pouches with accessory stylets. Abbreviations: an = accessory nerve; ap = accessory stylet pouch; as = accessory stylet; bl = blood vessel; br = brain; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; gd = gonoduct; i = intestine; ic = intestinal cecum; ip = intestinal pouches; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal vessel; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; rd = rhynchodaeum; sb = stylet basis; st = stomach; t = testis; vl = ventral brain lobe. Scale bars: A–G = 100 µm; H–N = 30 µm.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB7FFE8FDCDFCBBFBEA2D48.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB5FFE7FDDBFAACFBE12B12.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB5FFE7FDDBFAACFBE12B12.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBAFFE6FDE9FC65FD382AEF.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBAFFE6FDE9FC65FD382AEF.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBBFFE5FDD2FD4EFE632C22.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBBFFE5FDD2FD4EFE632C22.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258876/files/figure.png	https://doi.org/10.5281/zenodo.7258876	Fig. 10. A–G. Alvinonemertes dariae gen. et sp. nov., holotype (SIO-BIC N281), transverse histological sections. H–N. Alvinonemertes claudiae gen. et sp. nov., holotype (SIO-BIC N283), transverse histological sections. A. Anterior tip of head with proboscis pore. B. Brain region. C. Anterior brain region with cerebral canal (arrowhead). D. Stomach region with excretory canal. E. Posterior body region with testes. F. Lateral nerve cord with accessory nerve in stomach region. G. Proboscis armature, accessory stylet pouches with accessory stylets. H. Anterior tip of head with proboscis pore. I. Region anterior to cerebral ganglia with well-visible cerebral canal (arrowhead). J. Anterior brain region. K. Pyloric region. L. Proboscis and mid-dorsal vessel in stomach region. M. Proboscis armature, circular basis of central stylet. N. Proboscis armature, accessory stylet pouches with accessory stylets. Abbreviations: an = accessory nerve; ap = accessory stylet pouch; as = accessory stylet; bl = blood vessel; br = brain; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; gd = gonoduct; i = intestine; ic = intestinal cecum; ip = intestinal pouches; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal vessel; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; rd = rhynchodaeum; sb = stylet basis; st = stomach; t = testis; vl = ventral brain lobe. Scale bars: A–G = 100 µm; H–N = 30 µm.	Fig. 10. A–G. Alvinonemertes dariae gen. et sp. nov., holotype (SIO-BIC N281), transverse histological sections. H–N. Alvinonemertes claudiae gen. et sp. nov., holotype (SIO-BIC N283), transverse histological sections. A. Anterior tip of head with proboscis pore. B. Brain region. C. Anterior brain region with cerebral canal (arrowhead). D. Stomach region with excretory canal. E. Posterior body region with testes. F. Lateral nerve cord with accessory nerve in stomach region. G. Proboscis armature, accessory stylet pouches with accessory stylets. H. Anterior tip of head with proboscis pore. I. Region anterior to cerebral ganglia with well-visible cerebral canal (arrowhead). J. Anterior brain region. K. Pyloric region. L. Proboscis and mid-dorsal vessel in stomach region. M. Proboscis armature, circular basis of central stylet. N. Proboscis armature, accessory stylet pouches with accessory stylets. Abbreviations: an = accessory nerve; ap = accessory stylet pouch; as = accessory stylet; bl = blood vessel; br = brain; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; gd = gonoduct; i = intestine; ic = intestinal cecum; ip = intestinal pouches; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal vessel; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; rd = rhynchodaeum; sb = stylet basis; st = stomach; t = testis; vl = ventral brain lobe. Scale bars: A–G = 100 µm; H–N = 30 µm.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBBFFE5FDD2FD4EFE632C22.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB8FFE4FDD0FB75FBE229E3.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB8FFE4FDD0FB75FBE229E3.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB9FFE2FDA0FDB2FBEA2BBC.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB9FFE2FDA0FDB2FBEA2BBC.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258878/files/figure.png	https://doi.org/10.5281/zenodo.7258878	Fig. 11. A–G. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256), transverse histological sections. H–M. Tetrastemma strandae sp. nov., holotype (SIO-BIC N285), horizontal histological sections (H–I) and transverse histological sections (J–M). A. Anterior tip of head with proboscis pore. B. Brain region with well-visible cerebral canal (arrowhead). C. Proboscis with 10 proboscis nerves (arrowheads) in stomach region. D. Pyloric region. E. Intestinal region with ovaries. F. Anterior part of lateral nerve cord. G. Posterior part of lateral nerve cord located in body wall musculature. H. Longitudinal section through anterior tip with proboscis pore. I. Longitudinal section through the ventral part of the anterior tip. J. Intestinal region with testes. K. Proboscis in stomach region with 10 proboscis nerves (arrowheads). L. Proboscis armature. M. Lateral nerve cord in intestinal region. Abbreviations: ap = accessory stylet pouch; as = accessory stylet; br = brain; cc = cerebral canal; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; i = intestine; ic = intestinal cecum; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal-vessel; o = ovary; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; sb = stylet basis; t = testis; vc = ventral commissure; vl = ventral brain lobe. Scale: 100 µm.	Fig. 11. A–G. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256), transverse histological sections. H–M. Tetrastemma strandae sp. nov., holotype (SIO-BIC N285), horizontal histological sections (H–I) and transverse histological sections (J–M). A. Anterior tip of head with proboscis pore. B. Brain region with well-visible cerebral canal (arrowhead). C. Proboscis with 10 proboscis nerves (arrowheads) in stomach region. D. Pyloric region. E. Intestinal region with ovaries. F. Anterior part of lateral nerve cord. G. Posterior part of lateral nerve cord located in body wall musculature. H. Longitudinal section through anterior tip with proboscis pore. I. Longitudinal section through the ventral part of the anterior tip. J. Intestinal region with testes. K. Proboscis in stomach region with 10 proboscis nerves (arrowheads). L. Proboscis armature. M. Lateral nerve cord in intestinal region. Abbreviations: ap = accessory stylet pouch; as = accessory stylet; br = brain; cc = cerebral canal; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; i = intestine; ic = intestinal cecum; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal-vessel; o = ovary; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; sb = stylet basis; t = testis; vc = ventral commissure; vl = ventral brain lobe. Scale: 100 µm.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFB9FFE2FDA0FDB2FBEA2BBC.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBFFFE1FDAFFC1BFAF129C0.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBFFFE1FDAFFC1BFAF129C0.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258870/files/figure.png	https://doi.org/10.5281/zenodo.7258870	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	Fig. 7. Maximum likelihood (ML) tree for the monostiliferan supermatrix based on the concatenated four gene dataset (16S, COI, 18S, H3). Black circles indicate nodal support of 100/100/1.0; asterisks indicate nodal support of either 100/ or /1.0. Alternative branches found in the BI analysis are given as blue dotted lines. Sonnenemertes cantelli Chernyshev, Abukawa & Kajihara, 2015 and Micrura callima Sundberg & Gibson, 1995 were used for outgroup rooting. Specimens belonging to new species are given in bold. Specimen-ID, sampling locality, and depth (for deep-sea species) are provided.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBCFFE0FD98FE17FBF529E3.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258878/files/figure.png	https://doi.org/10.5281/zenodo.7258878	Fig. 11. A–G. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256), transverse histological sections. H–M. Tetrastemma strandae sp. nov., holotype (SIO-BIC N285), horizontal histological sections (H–I) and transverse histological sections (J–M). A. Anterior tip of head with proboscis pore. B. Brain region with well-visible cerebral canal (arrowhead). C. Proboscis with 10 proboscis nerves (arrowheads) in stomach region. D. Pyloric region. E. Intestinal region with ovaries. F. Anterior part of lateral nerve cord. G. Posterior part of lateral nerve cord located in body wall musculature. H. Longitudinal section through anterior tip with proboscis pore. I. Longitudinal section through the ventral part of the anterior tip. J. Intestinal region with testes. K. Proboscis in stomach region with 10 proboscis nerves (arrowheads). L. Proboscis armature. M. Lateral nerve cord in intestinal region. Abbreviations: ap = accessory stylet pouch; as = accessory stylet; br = brain; cc = cerebral canal; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; i = intestine; ic = intestinal cecum; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal-vessel; o = ovary; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; sb = stylet basis; t = testis; vc = ventral commissure; vl = ventral brain lobe. Scale: 100 µm.	Fig. 11. A–G. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256), transverse histological sections. H–M. Tetrastemma strandae sp. nov., holotype (SIO-BIC N285), horizontal histological sections (H–I) and transverse histological sections (J–M). A. Anterior tip of head with proboscis pore. B. Brain region with well-visible cerebral canal (arrowhead). C. Proboscis with 10 proboscis nerves (arrowheads) in stomach region. D. Pyloric region. E. Intestinal region with ovaries. F. Anterior part of lateral nerve cord. G. Posterior part of lateral nerve cord located in body wall musculature. H. Longitudinal section through anterior tip with proboscis pore. I. Longitudinal section through the ventral part of the anterior tip. J. Intestinal region with testes. K. Proboscis in stomach region with 10 proboscis nerves (arrowheads). L. Proboscis armature. M. Lateral nerve cord in intestinal region. Abbreviations: ap = accessory stylet pouch; as = accessory stylet; br = brain; cc = cerebral canal; cg = cephalic glands; cm = circular muscle layer; co = cerebral organ; dl = dorsal brain lobe; ec = excretory canal; i = intestine; ic = intestinal cecum; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mv = mid-dorsal-vessel; o = ovary; p = proboscis; pe = proboscis epithelium; pp = proboscis pore; py = pylorus; rc = rhynchocoel; sb = stylet basis; t = testis; vc = ventral commissure; vl = ventral brain lobe. Scale: 100 µm.	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
5F0F3852FFBCFFE0FD98FE17FBF529E3.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/7258872/files/figure.png	https://doi.org/10.5281/zenodo.7258872	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	Fig. 8. Live images of eumonostiliferous hoplonemerteans collected along the Costa Rica margin and the NE Pacific. A. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N112). B. Chernyshevia escarpiaphila sp. nov., paratype (SIO-BIC N266). C. Octocoral Paragorgia sp. (SIO-BIC Co3054) with several specimens of Alvinonemertes dariae sp. nov., holotype (arrows; ex SIO-BIC N262). D. Alvinonemertesdariaesp.nov.,holotype(exSIO-BICN262).E.Antipathariancoral(SIO-BICCo3031) with specimens of Alvinonemertes dagmarae sp. nov., holotype (SIO-BIC N260). F. Alvinonemertes christianeae sp. nov., holotype (SIO-BIC N253). G. Alvinonemertes claudiae sp. nov., holotype (ex SIO-BIC N231). H. Alvinonemertes tatjanae sp. nov., holotype (SIO-BIC N119). I. Eumonostilifera (SIO-BIC N259). J–L. Tetrastemma sundbergi sp. nov., holotype (SIO-BIC N256) whole animal (J), dorsal view of head (K), and ventral view of head (L). M. Tetrastemma polyakovae sp. nov. (MZUCR Nemertea Collection MZUCR-101-01).N. Tetrastemma polyakovae sp. nov., holotype (SIO-BIC N258), with everted proboscis. O. Eumonostilifera (SIO-BIC N109).	2022-10-27	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin		Zenodo	biologists	Sagorny, Christina;Döhren, Jörn von;Rouse, Greg W.;Tilic, Ekin			
