taxonID	type	description	language	source
9A0E87F0FF91FFC7FF2CD6CCFBBCFC3F.taxon	description	Description: — Frustules apically sigmoidally arched (in an open V-shaped girdle view), producing a raphe valve with a concave valve center (Figs 22, 23). Valves elliptic with swollen central area and subcapitate apices (Figs 1 – 21, 24 – 36), less noticeable in smaller valves. Length: 10.2 – 35.7 µm, width: 3.1 – 4.3 µm, stria density 26 – 28 (up to 30 toward apices) in 10 µm in RV, and 26 – 27 (up to 32 toward apices) in 10 µm in SV, 1 – 4 areolae per stria on both valves. Hymenes, girdle bands and plastids not determined. RV with narrow, lanceolate, raised axial area (externally [Figs 37 – 39] and internally [Fig. 40]), tapering into a pointy end at valve apex, becoming enlarged in central area where it connects with the central stauros (Figs 37 – 40). Central stauros with bow-tie shaped fascia (rarely apically rhomboid in some larger valves) (Figs 1 – 21), with raised central nodule in external view (Figs 37 – 39, 41), flat in internal view (Fig. 40). Virgae wider than striae except at valve ends where they become slender and rod-shaped, straight or zig-zagged due to polygonal shape of areolae (Figs 38, 39). Virgae lower with respect to axial area and at same level as striae in internal and external views (Figs 37 – 40). Raphe uniformly filiform and straight, with proximal ends opposite to each other (Figs 37 – 39). Distal fissures straight and extending over striation regions at both poles (Fig. 39, white arrows). Internally, proximal raphe ends with a small capitate terminus (Fig. 40, white arrows) and distal ends terminating in low helictoglossae fused with a low thickening of valve apex (Fig. 40, black arrow). Striae varying from convex toward valve central area (striae frequently lacking or being shorter on central stauros) becoming extremely convex and noticeably denser toward apices (Figs 37 – 39, 41). Areolae round or elliptic toward the central sternum, becoming transapically elongated toward valve face / mantle transition, and densely packed and polygonal at valve extremes (Fig. 38, open arrows), usually with two large areolae on both sides of distal raphe end (Figs 37, 39). A single row of slit-like areolae present on valve mantle, stopping short of the very apex (unclearly seen in Fig. 40). A clear area runs around edge of the face / mantle junction (Figs 37 – 39). SV (Figs 41, 42) with wider, flat (only observed in internal view) lanceolate axial area, more or less broad at valve ends. Central nodule is only slightly raised internally. Virgae of same characteristics as in RV, but at same level as striae and axial area (only internal views available). Striae of same general characteristics as those of RV, except they are evenly spaced (some are short) at valve central area, they become less convex toward the valve apices, and single row of elongated striae on the valve mantle are continuous around valve apex. The clear area around edge of the face / mantle junction is less noticeable.	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
9A0E87F0FF91FFC7FF2CD6CCFBBCFC3F.taxon	materials_examined	Type: — U. S. A. Texas, Uvalde County, Sabinal River, 29.491 N, 99.493 W, NAWQA, August 7 th, 1996 (holotype slide ANSP GC 102382 a = Fig. 10)	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
9A0E87F0FF91FFC7FF2CD6CCFBBCFC3F.taxon	etymology	Etymology: — The species epithet honors our late colleague Luc Ector. Luc promoted a major advancement in the taxonomy of the genus Achnanthidium through a series of courses and workshops that were the foundation of the taxonomy used in the European Water Framework Directive. The special issue in Algological Studies (2011: 136 / 137), edited by Luc and the result of one of those workshops, presented critical analyses of type material and new species in Achnanthidium from around the world, a foundation for current studies in this genus.	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
9A0E87F0FF96FFC5FF2CD2CAFB27F7B4.taxon	description	Description: — Frustules rectangular in girdle view (not shown here). Valves linear to elliptic with rostrate apices (Figs 43 – 59). Length: 17.0 – 54.4 µm, width: 4.1 – 5.2 µm, stria density 23 – 26 (up to 29 toward apices) in 10 µm in RV, and 23 – 26 (up to 34 toward apices) in 10 µm in SV. Hymenes, girdle bands and plastids not determined. RV with lanceolate, raised axial area (more in internal Fig. 61 than in external view Fig. 62), broad at valve ends (Figs 60 – 63), becoming enlarged in the central area where it assumes a circular or rhomboid shape (Figs 43 – 53). Central area with slightly raised central nodule in external view (Figs 60, 61), clearly raised in internal view (Figs 62 and 63), and with shortened striae on both sides (Figs 60 – 63). Virgae wider than striae becoming slender toward the valve apices, lower with respect to axial area and at same level as striae in external and internal views (Fig. 61). Raphe filiform and straight, externally with proximal ends expanded and opposite to each other (Fig. 60, white arrows), and distal fissures expanded, close-hooked in shape and strongly deflected toward same direction, surfacing gradually at valve face / mantle junction, within the striation region (Fig. 61, white arrows). Internally, proximal raphe ends curved and deflected in opposite directions (Fig. 63, white arrow), distal raphe ends terminate in low helictoglossae located at a distance from valve apices (Fig. 63, black arrow). Striae varying from parallel at valve central area, only sometimes becoming slightly convex toward the apices, short striae on both sides of central area present (Figs 60 – 63). Areolae visible under LM, round, elliptic or slit-like (Figs 43 – 53). A single row of elliptic areolae present on valve mantle, more slit-like in shape and interrupted by clear area at valve apex (Figs 60, 63). A clear area runs around the edge of the face / mantle junction (Figs 60 – 61). SV with sunken lanceolate axial area (only observed in external view), broad at valve ends (seen as an expansion as the distal end of striation is reached) (Figs 64, 65). Virgae wider than striae, becoming slender toward valve apices, but in general wider than those in RV at the same region (compare Figs 63 and 65). Striae at same level as virgae. Central area with evenly spaced striae, rarely shortened (Figs 64, 65).	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
9A0E87F0FF96FFC5FF2CD2CAFB27F7B4.taxon	materials_examined	Type locality: — U. S. A. Texas, Uvalde County, Sabinal River, 29.491 N, 99.493 W, NAWQA August 7 th, 1996 (holotype slide ANSP GC 102382 a = Fig. 48)	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
9A0E87F0FF96FFC5FF2CD2CAFB27F7B4.taxon	etymology	Etymology: — The species epithet refers to the fact that this diatom has remained undiscovered despite the rather long history of studies of algae, particularly diatoms, in Texas.	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
9A0E87F0FF96FFC5FF2CD2CAFB27F7B4.taxon	biology_ecology	Ecology for both taxa: — While A. lucectorii sp. nov. was found in 3.1 % relative abundance in a count of 600 valves, A. enigmaticum sp. nov. was only found in a relative abundance of <1 %. The dominant accompanying taxa in the sample were Encyonema neogracile Krammer (1997 a: 177, with a relative abundance of 26.8 %), Delicata delicatula (Kützing) Krammer (2003: 113, 20.5 %), Encyonopsis microcephala (Grunow) Krammer (1997 b: 91, 11.8 %), Ulnaria ulna (Nitzsch) Compère (2001: 100, 7.8 %), Achnanthidium caledonicum (Lange-Bertalot) Lange-Bertalot (1999: 277, 5.3 %), Navicula cryptotenella Lange-Bertalot (1985: 62, 3.0 %) and other species in relative abundances <2 %. Though the new taxa were in low abundances as to consider the Sabinal River their optimal habitat, the available physico-chemical for July 31, 1996 were: river discharge 3.7 L ̔ s- 1, water temperature 31 ° C, electric conductance 476 µS ̔ cm- 1, dissolved oxygen 6.9 mg ̔ L- 1, pH 7.8, total nitrogen 0.31 mg ̔ L- 1, and orthophosphates <0.01 mg ̔ L- 1. Based on the autecology of the assemblage found in type material, the habitat of the new species can be characterized as an oligotrophic site with water of good quality, with low nutrients, low electric conductance and circumneutral pH, which corresponds to the actual parameters measured on site. Based on the presence of A. caledonicum and N. cryptotenella, the type locality could have a calcareous, alkaline influence (Van Dam et al. 1994, Hofman et al. 2011). K. Manoylov recently found, in periphyton collections from May 2022, A. lucectorii sp. nov. in Roy Creek, Austin, TX (relative abundance <1 %) and A. enigmaticum sp. nov. in Hamilton Creek and Deadmans Creek, close to Austin, TX (relative abundance <1 %). Specific sampling locations were not available to us, but based on public reports the three creeks close to Austin, TX are either under private protection or within rangeland.	en	Morales, Eduardo A., Manoylov, Kalina M. (2023): Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U. S. A. Phytotaxa 592 (1): 1-20, DOI: 10.11646/phytotaxa.592.1.1, URL: http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
