Epigodromia mclayi Prema & Cubelio, 2024, sp. nov.
Year: 2024
Type: other
Abstract: Epigodromia mclayi sp. nov. (Figs. 1A–B, 2, 3A–E, 4, 5A–B, 6A–B) Material examined. Holotype: 1 male (cw 11.43, cl 10.33 mm), (IO /SS/BRC/00370), FORVSS stn. 39217, slope, off the coast Tamil Nadu, southeastern Arabian Sea, 7°25’12’’N, 77°31’12” E, 113 m, coll. Vinay Padate, 04 December 2019.— Paratype: 1 male, (cw 10.29, cl 9.04 mm), (IO /SS/BRC/00371), FORVSS stn. 23631, off the coast Tamil Nadu, southwestern Bay of Bengal, 107 m, 11°58’48” N, 80°05 60” E, coll. Smitha C.K, 16 July 2005. Comparative material examined. Epigodromia areolata (Ihle, 1993): 1 male (cw 13.2, cl 11.9 mm) (ZRC 2001.521), Balicasag Island, Panglao, Bohol, Visayas, Philippines, 200–300 m, coll. 28 November 2001 [examined by Peter K.L. Ng, photographs received]; 1 male (cw 16.0, cl 14.0 mm) (WAM-C 50514), Queensland, 164 m, coll. W. Goode, 1965 [specimen examined by late Prof. Colin McLay; photographs received]. — Epigodromia gilesii (Alcock, 1900): holotype, male (ZSI 5621-34/9), Malabar coast, Marine Survey; 2 males (cw 6.8, cl 6.64; cw 5.8, cl 6.05 mm) (IO /SS/BRC00/372), FORVSS stn. 34324, Malabar coast, Southeastern Arabian Sea, India, 32 m, 9°57’36” N, 75°35’24” E, coll. Ishwarya Gopal, 15 August 2015.— Epigodromia ebalioides (Alcock, 1900): holotype, male (ZSI 182-3/10), Karachi, Marine Survey. [Note: E. gilesii Alcock, 1900 and E. ebalioides (Alcock, 1900) which are preserved in the ZSI has been examined by the first author but unable to take the measurements of the specimens due to its fragile condition. The photographs were received upon request from: https://zsifis.nic. in/ImageRequest/GetByCategory/10] Etymology. This species is dedicated to and named in honour of the late Prof. Colin McLay (University of Canterbury) for his tremendous contribution to the taxonomy and systematics of the brachyuran families, particularly the Dromiidae, which has been most helpful in the present study and for his generous mentorship and help to the authors. Description. Carapace wider than long, subcircular, areolate; entire carapace granulated, small granules on anterior region, larger and dense granules posteriorly; grooves between areolae smooth; regions well defined; short frontal groove between rostral and first anterolateral lobe (Figs. 1A, B, 2A, 4A, 5A, 6A). Cervical and branchial grooves distinct; mesogastric region convex, with prominent, fine granules, three poorly defined protuberances, anterior one small, rounded, followed by two larger protuberances; small oval-shaped protuberances side by side in protogastric region; urogastric region with two equally divided small protuberances; cardiac region broadly convex, nearly triangular, granulated, well defined by grooves (Figs. 1A, B, 5A). Branchial region anteriorly with four fused, prominent protuberances, connected with supraorbital ridge longitudinally and with second anterolateral lobe forms concave surface and deep groove; branchial notch visible with posterolateral node and larger conical tooth; posterior branchial areas convex, evenly granulated with larger granules (Figs. 1A, B, 5A). Rostrum tridentate, lateral teeth long, separated by a U-shaped sinus; borders of lateral rostral teeth granulated, concave, median tooth short, pointed, triangular, clearly visible dorsally (Fig. 1A, B, 2A– C). Anterolateral margin armed with two granulated lobes, first lobe at the level of anterior corner of buccal frame, and separated from it by a concave groove, second lobe smaller, rounded, projected laterally, continuous with posterolateral margin, covered in larger rounded granules; posterior carapace margin distinctly concave (Figs. 1A, 2A, B, 4A, 5A). Supraorbital border slightly concave, smooth, small pointed tooth followed by post-supraorbital border integration with carapace surface, no orbital fissure, and visible tooth at inner corner (Figs. 2B, 5A). Suborbital lobe triangular, pointed, granular (Fig. 2C). First segment of antenna much wider than long, tuberculate, second segment longer, surface rough, third segment inserted at an angle (Figs. 2B–C, 4B). Subhepatic area deeply concave, densely granulated (Fig. 2C). Chelipeds well developed, covered with line of larger, rounded granules; merus long, but shorter than propodus; carpus with two obtuse, distal tubercles; propodus with two tubercles near carpal articulation along anterior and posterior margins, three tubercles at base of fingers; outer surface of movable finger with rounded granules, fixed finger surface smooth, possesses numerous setae; fingers strongly curved with 6 or 7 teeth, meeting at tips, pointed tip of dactylus fitting in the bifid tip of pollex (Figs. 1A, 2E–H). Ambulatory legs, first two pairs shorter than chelipeds, tuberculate, largely granulated, with rounded nodules and few short bristles; dactyli as long as propodi, inner margins with 5–7 tiny spines of similar size; P4–5 reduced, tuberculate, granulated, with short and long setae, outer surfaces of propodi with 3 spines of similar size, inner posterior end with single spine opposed to dactyli, dactyli of both legs deeply curved (Figs. 1A, 2I–J, 4D–G). Male pleon with six free somites; telson wider than long, lateral margins with minor acute spine; uropod plates large, visible externally; median ridge strongly developed; outer surface covered with dense, smaller granules; somites 2–6 with two transverse rows of granulated lobules: upper one with continuous lobe and lower one divided into two lobes; somites 2 and 3 with transverse lobules ornamented with continuous flattened granules (Figs. 3A, 4H, 5B, 6B). G1 semi-rolled, setose with a pointed lobe, G2 needle-like, pointed tip (Figs. 3B–E, 4I–K). Fresh colouration. Brownish in colour with red spots on the carapace. Remarks. Epigodromia mclayi sp. nov., fits well within the genus as defined by McLay (1993, 1998) and Guinot & Tavares (2003), particularly in the following characters: wider, subcircular carapace, areolate, anterolateral margin with two broad granulated lobes; rostrum with three lobes with short median lobe, pointed, triangular, bluntly rounded, lateral lobes; coxae of third maxillipeds separated by a gap by triangular shape plate with the sternum; much larger cheliped in males with proximal tooth along the cutting edge; last two ambulatory legs reduced; male pleon having six free somites by a strongly granulated median ridge with transverse lobes. Among the 10 species of Epigodromia currently recognized (McLay 1998; Ng et al. 2008; Poore & Ahyong 2023), E. mclayi sp. nov., is morphologically most similar to E. areolata (type locality: Timor Island, South China Sea), particularly in the general outline of the carapace and the division of the anterolateral margin whereby second lobe is exceptional with 5–9 distinct blunt teeth, and has a concave margin with anterior margin of the buccal frame, and third lobe continues with posterolateral margin, one large granulated conical tooth and covered in larger rounded granules (Figs. 1B, 4A), and number of spines in the dactylus of ambulatory legs (Fig. 4D, E). Some consistent morphological features, however, distinguish the two species: (1) the carapace is wider than long and subcircular, areolate, outline is more rounded and granular, posterolateral margin with more rounded granules, posterior carapace margin is distinctly concave in E. mclayi sp. nov. (Figs. 1A, B, 2A, 4A, 5A, 6A) (versus the carapace slightly wider than a long, more flattened, outline with two granulated lobes and ornamented with sharp granules,the posterolateral margin with sharp granules, posterior carapace margin is moderately concave in E. areolata; Fig. 1C–F); (2) mesogastric region convex, prominent, fine granules, three poorly defined protuberances, anterior one rounded and small, followed by two larger protuberances in E. mclayi sp. nov. (Fig. 1A, B) (versus mesogastric region convex and comparatively clearly defined protuberances with larger granules, anterior one small and followed by two larger protuberances in E. areolata; Fig. 1C–F); (3) cardiac region broadly convex, nearly triangular structure towards posterior margin, finely granulated, and visible grooves in between posterolateral margin in E. mclayi sp. nov. (Figs. 1A, B, 2A) (versus cardiac region broadly convex, round appearance with larger granules, posterolateral margin fused in E. areolata; Fig. 1C–F); (4) branchial notch clearly visible forming narrow gap between second anterolateral lobe and the posterolateral node, followed by one larger conical tooth present in E. mclayi sp. nov. (Figs. 1A–B, 2A, 4A) (versus branchial notch clearly visible, and fused with posterolateral margin, conical tooth absent in E. areolata; Fig. 1C–F); (5) rostrum tridentate, lateral teeth distinctly curved out, triangular, longer than median tooth more triangular in E. mclayi sp. nov. (Fig. 1A–B) (versus rostrum tridentate, lateral teeth slightly curved out, slightly longer than median tooth, median tooth deflexed in E. areolata; Fig. 1C–F); (6) chelipeds equal, larger, outer surface covered with line of rounded granules, including movable finger, and outer surface of fixed finger smooth and possess numerous setae in E. mclayi sp. nov. (Figs. 1A, 2E–H) (versus chelipeds equal, larger, outer surface with densely packed with larger sharp granules, including bases of fingers in E. areolata; see McLay & Hosie 2022: fig. 16B–C; Fig. 1C, E); (7) ambulatory legs, inner margins of dactyli of first two pairs ambulatory legs armed with 5–7 tiny spines of similar size in E. mclayi sp. nov. (Fig. 4D, E) (versus inner margins of dactyli of first two pairs of legs armed with 7–8 small spines in E. areolata; see McLay (1993) and it is also confirmed in Philippines specimen (pers. comm P.K.L. Ng)); (8) the telson of the male pleon is much wider than long, pronounced flange on the lateral margins and anterior margin of somite 6 in E. mclayi sp. nov. (Figs. 3A, 4H, 5B, 6B) (versus the telson of the male pleon with smooth margins, slightly wider than
Authors: Prema, Mani, Cubelio, Sherine Sonia
Institution: Centre for Marine Living Resources and Ecology
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6967737434
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