taxonID	type	description	language	source
03FD87A0FFC3960C9DA5FE3295EDDC21.taxon	description	Number of valid species: 44.	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFC2960D9DA5FB77908BD885.taxon	diagnosis	Diagnosis: Cuticle punctate, with transverse rows of dots; lateral differentiation may be presented as enlarged dots arranged irregularly, or more sparsely, or in transverse or longitudinal rows. Head sensilla arranged in three circles, posterior two being at almost the same level and usually setiform (sometimes jointed). Anterior sensilla are often papilloid and indistinct. Somatic setae may be present or absent. Amphidial fovea large, round with interrupted posterior rim or nearly comma-shaped (spiral in one species). Buccal cavity armed with two or more solid teeth (indiscernible in two species), teeth minute or large, often eversible (two elongated and narrow stylet-like teeth present in two species). Spicules of a peculiar construction - flattened and strongly broadened proximally. Rodshaped gubernaculum without apophysis and bifurcated at its distal end. Spermatozoa giant, pear-shaped, often structurally complex. No precloacal supplements. Tail long, filiform. Marine, mostly deep-sea.	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFC296079DA5F96F95FBDEC9.taxon	materials_examined	Material studied. Holotype male (MOUFPE 0013), 1 paratype female (MOUFPE 0014), 2 paratypes males (220 NM LMZOO-UFPE). Type locality. Santos Basin, Rio de Janeiro, Brazil. Holotype male and paratype female: 24 ° 74 ′ 00 ″ S 43 ° 15 ′ 11 ″ W (2000 m depth),	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFC296079DA5F96F95FBDEC9.taxon	etymology	Etymology. In reference to the shape of the teeth, similar to a stylet.	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFC296079DA5F96F95FBDEC9.taxon	materials_examined	Holotype male. Body cylindrical 888 μm long (706 μm excluding tail) (Figs. 1 A, 3 A). Body attenuated at extremities, strongly narrowed anterior end (Figs 1 B, 3 B). Punctuated cuticle, the points are so delicate that it is difficult to see. Cuticular pores not observed. Anterior sensilla arranged in the 6 + 6 + 4 pattern: six inner labial papilliform sensilla, six outer labial papilliform sensilla and four cephalic setiform sensilla (2 μm long) (Fig. 3 C), corresponding to 83 % of head diameter. Ventrally spiral amphidial fovea (single-spiral), rounded with posterior interruption, located 26 µm (8.7 x head diameter) from anterior end and occupying 71 % of corresponding body diameter (Figs. 1 B, 3 C). Cervical setae present, however it is likely that some of these have been lost. In the holotype only one pair of cervical setae were observed, the first (latero-subdorsal) is 17 µm and the second (latero-subventral) is 21 µm from the posterior edge of the amphidial fovea. Buccal cavity reduced. Cheilostom rugae indiscernible under a light microscope. Two long and thin protractible stylet-like teeth (42 µm), about 19 % of pharynx length (Fig. 3 C). Pharynx (220 μm long) with narrowing in the second third of its length, and expanded in the final third forming an elongated basal bulb (Fig. 3 B). Bulb occupying 23.4 % of pharynx length. Cardia embedded in intestine. Nerve ring situated at 51 % of the pharynx length, from anterior end (Fig. 3 B). Ventral gland and secretory-excretory pore not observed. Reproductive system with single anterior outstretched testis on right side of intestine (208 μm), occupying about 29 % of body length (excluding tail) (Fig. 3 A). Spicules curved, expanded and flattened in proximal portion (Figs. 1 C, 3 E). Gubernaculum narrow, slightly curved. Distal region so thin that it is not possible to differentiate the final bifurcation. Precloacal supplements absent. Mature spermatozoid measuring 29 x 6 μm. Three caudal glands. Tail conical-cylindrical with long filiform portion (177 µm or 14 x cloacal diameter) (Figs. 1 D, 3 D). Paratype female. Similar to male. Body measuring 979 μm in length (751 μm excluding the tail), and maximum diameter 12 μm (Fig. 4 A). Cephalic sensilla equivalent to 50 % corresponding body diameter (Fig. 4 C). Amphidial fovea, occupying 67 % of corresponding body width and located 15 µm (3.75 x head diameter) from anterior end (Figs. 2 A, 2 C, 4 C). Its size is similar to that of the male, but in females it is located more anteriorly on the body. Buccal cavity and pharynx similar to that of male (Fig. 4 B). Teeth resemble a stylet in shape, as in males, but are smaller in the females (5 μm, about 3 % of pharynx length) (Figs. 2 C, 4 C). Basal bulb occupying 75 % of the corresponding body diameter and 16 % of pharynx length (Fig. 4 B). Nerve ring not visible. Ventral gland and secretory-excretory pore not observed. Cardia embedded in intestine. Vulva located 493 μm from anterior end, at 66 % of body length, from anterior end excluding the tail. Two opposed, reflexed and antidromous ovaries (anterior ovary lying to right of intestine, posterior ovary to left of intestine) (Figs. 2 B, 4 D). Anterior and posterior ovary measuring respectively 288 and 156 μm. Tail conical-cylindrical with long filiform portion (Fig. 2 D).	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFC296079DA5F96F95FBDEC9.taxon	diagnosis	Diagnosis. Acantholaimus pugious sp. n. is characterized by narrow and elongated anterior end, two thin and long stylet-like teeth, amphidial fovea far from the anterior end (3.8 – 8.6 x head diameter) occupying most of the corresponding body diameter, cuticle with delicate and faint punctations and cervical setae without a specific distribution pattern. Differential diagnosis. The new species shares the following features with Acantholaimus microdontus: the relatively large amphidial fovea (78 – 85 % of corresponding body diameter in A. microdontus and 67 – 81 % in A. pugious sp. n.); elongated basal bulb and de Man’s ratio c (4.4 – 5.1 in A. microdontus and 3 – 5 in the new specie). However, A. microdontus has distinct characteristics such as maximum body diameter about 2 – 4 times wider than A. pugious sp. n.; the length of the spicules (25 – 32 μm in A. microdontus vs 18 – 21 μm in A. pugious sp. n.), and the de Man’s ratio a 1.8 – 2.6 times smaller than in the new species. Acantholaimus veitkoehlerae shares with the new species features such as: presence of the elongated basal bulb; amphidial fovea diameter (6 – 9 μm in A. veitkoehlerae and 5 – 8 μm in the new species); de Man’s ratio b (4.6 – 6.6 µm in A. veitkoehlerae and 4 – 6 µm in A. pugious sp. n.). Nevertheless, A. veitkoehlerae presents numerous somatic setae along the entire body, with these setae absent in the new species; gubernaculum 1.7 – 3.3 times longer that in A. pugious; buccal cavity armed with five sclerotized onchia usually found in the genus, while the new species possesses two onchia resembling a stylet in shape. Acantholaimus angustus resembles the new species in terms of the presence of an elongated bulb, de Man’s ratio b (5 – 6.2 in A. angustus and 4 – 6 in A. pugious), and ratio between total body length and tail length (4.7 – 5.5 in A. angustus and 3 – 5 in A. pugious). Yet, A. angustus differs from A. pugious sp. n. in the following features: six outer labial sensilla visible in A. angustus (6 μm long) whereas in A. pugious the sensilla are papilliform; A. angustus possesses four setae close to the amphidial fovea, while in A. pugious the corresponding structures are absent; cephalic setae in A. angustus are 5 times longer than in the new species; the amphidial fovea in males of A. angustus is located at 0.93 times head diameter from the anterior end, while in A. pugious the amphids are 6 – 8.7 times head diameter from anterior end.	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFCB96019DA5FF129565DBDD.taxon	materials_examined	Material studied. Holotype male (MOUFPE 0015), paratype juvenile (MOUFPE 0016). Type locality. Santos Basin, Rio de Janeiro, Brazil. Holotype male and paratype juvenile: 24 ° 74 ′ 00 ″ S 43 ° 15 ′ 11 ″ W (2000 m depth),	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFCB96019DA5FF129565DBDD.taxon	etymology	Etymology. In reference of the number of teeth (two).	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFCB96019DA5FF129565DBDD.taxon	materials_examined	Holotype male. Body cylindrical (1116 μm long excluding tail) and attenuated at extremities (Fig. 7 A), head diameter corresponding to 23 % of maximum body diameter (Fig. 5 A). Cuticle punctuated with larger and more evident dots in anterior region up to amphidial fovea end, and in tail (Figs. 5 G, 7 C, 7 D). Lateral differentiation not observed. Cuticular pores randomly scattered, extending along entire body length. Anterior sensilla arranged according to 6 + 6 + 4 pattern: six inner labial papillae, six outer labial (6 µm) and four cephalic setae (8 μm long), corresponding to approximately 1.2 times the head diameter; last two circles (external labial and cephalic) almost at the same level (Figs. 5 B, 7 C). Ventrally spiral amphidial fovea rounded with posterior interruption (single-spiral), located 19.2 µm (2.67 x head diameter) from anterior end and occupying 79 % of corresponding body diameter (Figs. 5 B, 7 C). Four cervical setae, typically found in the genus, located posteriorly to each amphidial fovea (2 in the latero-subdorsal region and 2 in the latero-subventral region) and difficult to see. Four pores, in the same position as the typical cervical setae, are visualized (Figs. 5 D, 5 E). Somatic setae present only in precloacal region, two at the same level and distant from the cloaca (20 µm), positioned in the latero-subdorsal and latero-subventral region and one setae ventrally located (12 µm of the cloaca) (Fig. 7 D). Buccal cavity reduced. Cheilostom rugae indiscernible under a light microscope. Two long and thin stylet-like protractible teeth (37 µm long); proximal part of teeth curved towards the dorsal and ventral regions of the body (Figs. 5 C, 7 C). Pharynx (164 μm long) with basal bulb (48 µm length x 22.5 μm diameter) occupying 29 % of pharynx length (Fig. 7 B). Cardia embedded in intestine. Nerve ring situated at 59 % of the pharyngeal region length. Ventral gland and secretory-excretory pore not observed. Reproductive system with single anterior outstretched testis on right-hand side of intestine (179 μm long), occupying about 16 % of body length (excluding tail) (Fig. 7 A). Spicules curved, expanded and flattened in proximal portion (Figs. 5 F, 7 E). Gubernaculum with proximal portion slightly curved and bifurcated distal end (Fig. 7 E). Apophysis absent. Precloacal supplements absent. Caudal glands difficult to differentiate. Tail conical-cylindrical with long filiform portion (Figs. 5 G, 7 D). Distal portion of the tail is broken off. Paratype juvenile. The juvenile analyzed may be in the early stage of development, because the genital primordium is not visible. Juvenile shared the following adult features: Body cylindrical and attenuated at extremities (617 μm long) (Figs. 6 A, 8 A). Punctuated cuticle, the points are so delicate that it is difficult to see at the cloacal region. Dots larger and more evident in the tail (Fig. 8 C). Cuticular pores not observed. Cephalic arrangement similar to the male (Fig. 8 B). Somatic and cervical setae absent. Ventrally spiral amphidial fovea rounded with posterior interruption (single-spiral), located 9.6 µm (2 x head diameter) from anterior end and occupying 67 % of corresponding body diameter (Figs. 6 C, 8 B). Buccal cavity similar to that observed in the male. Two long and thin protractible teeth which resemble a stylet in shape (29.4 µm) (Figs. 6 B, 8 B). Pharynx similar to that in adults (120.6 μm). Tail conical-cylindrical with filiform end portion (Figs. 6 D, 8 C). Spinneret short.	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
03FD87A0FFCB96019DA5FF129565DBDD.taxon	diagnosis	Diagnosis. Anterior end narrow, cuticle with more evident dots in anterior region (up to amphidial fovea end) and tail; cuticular pores do not present a specific distribution pattern. Anterior sensilla arranged with six inner labial papillae, six outer labial and four cephalic setae (last two circles almost at the same level). Teeth long and thin (similar to stylet), protractile, with proximal part of teeth curved, amphidial fovea occupying most of the corresponding body diameter (67 – 79 %), located 2 – 2.67 times the head diameter from the anterior end. Differential diagnosis. Firstly, it is important to establish that only the males of the species mentioned in this section were compared, since the females were not found. The new species shares the following features with Acantholaimus iubilus: cuticle punctuated with larger and more evident dots in anterior and tail region; cloacal diameter (30 µm in A. iubilus and 30.9 µm in the new specie) and the amphid diameter (12 µm in A. iubilus and 13.2 µm in A. bidentatus sp. n.). However, these species differ in terms of the proportion that the amphidial fovea occupy in relation to the corresponding body diameter (near a half in A. iubilus vs more than ¾ in the new species) and the number of teeth observed in the new species (2) is smaller than the number described for A. iubilus (5). Moreover, lateral differentiation is absent in A. bidentatus sp. n. The new species resembles the males of Acantholaimus robustus, in terms of the number of teeth in the pharyngostome (2); the absence of lateral differentiation and the amphidial diameter (11 – 14 µm in A. robustus and 13.2 µm in the new species). However, the males of A. robustus differ from those of A. bidentatus sp. n. in the following features: presence of numerous somatic setae along the entire body; the amphidial fovea occupy a smaller proportion in relation to the corresponding body diameter (52 – 70 % in A. robustus vs 79 % in A. bidentatus sp. n.) and present longer spicules. Acantholaimus pugious sp. n. resembles A. bidentatus sp. n. in terms of the number of teeth in esophastoma (2) and the proportion that the amphidial fovea occupy in relation to the corresponding body diameter (71 – 81 % in A. pugious sp. n. and 79 % in A. bidentatus sp. n.). Meanwhile, the body length of A. pugious sp. n., without the tail, is between 1.8 – 2 times shorter and maximum body diameter between 2.2 – 2.8 times smaller when compared to A. bidentatus sp. n.	en	Manoel, Alex, Esteves, André Morgado, Neres, Patrícia Fernandes (2022): Two new species of Acantholaimus (Nematoda, Chromadoridae) from the deep southeastern Atlantic (Santos Basin). Zootaxa 5209 (2): 238-256, DOI: https://doi.org/10.11646/zootaxa.5209.2.5
