Munidopsis kadal, Tiwari & Padate & Cubelio & Osawa, 2022

Tiwari, Shivam, Padate, Vinay P., Cubelio, Sherine S. & Osawa, Masayuki, 2022, Squat lobsters of the genera Raymunida Macpherson & Machordom, 2000 and Munidopsis Whiteaves, 1874 (Decapoda: Anomura: Galatheoidea) from the Indian Exclusive Economic Zone, with descriptions of three new species, Journal of Natural History 56, pp. 1819-1839 : 1834-1837

Munidopsis kadal sp. nov.

( Figures 3 (e), 3)

urn:lsid:zoobank.org:act:04C22864-27A5-4DFF-BF50-83D50DDBD984

Type material

Holotype. India • ♂ (PCL 5.2 mm, CW 5.0 mm); south-eastern Arabian Sea , off Kerala; FORVSS stn. 341I06; 10.99°N, 74.98°E; 1018 m depth; naturalist’s dredge; 17 June 2015; N. Saravanane leg.; CMLRE IO /SS/ANO/00146.

Type locality

India: South-eastern Arabian Sea , off Kerala; 10.99°N, 74.98°E; 1018 m depth .

Etymology

The species name is derived from the Malayalam word for ‘sea’. The name is used as noun in apposition.

Diagnosis

Anoplonotus group. Carapace dorsally uneven,covered with numerous granules and low small tubercles; epigastric bulges blunt, each bearing tuberculate ridge anteriorly; posterior cardiac region widely triangular; lateral margins subparallel, unarmed, each with rounded anterolateral angle. Rostrum narrow subtriangular, nearly horizontal, with mid-dorsal granular carina extending between epigastric bulges; width at base about 0.4 of distance between anterolateral angles of carapace. Thoracic sternite 4 broad, 2.6 times wider than, and not contiguous to, sternite 3; anterolateral margins gently concave. Pleonal tergites unarmed, tergites 2–4 each with elevated transverse ridge anteriorly, tergites 2 and 3 with posterior transverse ridge. No eye spines. Antennular article 1 with 2 strong distal spines, ventrodistal spine larger than dorsodistal spine. Antennal peduncle overreaching distal corneal margin by half length of article 4, article 1 with small subacute ventromesial projection. Mxp3 with 2 ventral spines, dorsal margin distally with distinct spine. P1 slender, 3.3–3.4 times PCL, unarmed, with numerous coarse granules; fingers 0.9 length of palm, not gaping when closed, dactylus with low tooth proximally on cutting edge. Epipods absent from P1–4.

Description of holotype

Carapace ( Figures 3 (e), 3(a, 3)) (exclusive of rostrum) quadrangular in general outline, 1.1 times as long as wide; lateral margins subparallel, each with small notch at lateral end of anterior cervical groove. Dorsal surface with regions well delineated by deep depressions, uneven in lateral view, unarmed, covered with granules and low small tubercles. Hepatic region not elevated. Gastric region strongly convex, with pair of blunt epigastric bulges, each bulge delimited anteriorly by tuberculate ridge. Cervical grooves deep. Cardiac region subdivided into anterior and posterior parts by deep transverse groove; posterior part widely triangular, more elevated than gastric region. Posterior branchial region subdivided into 2 parts by deep transverse groove. Frontal margin behind ocular peduncles oblique, gently convex between ocular and antennal peduncles; antennal spine absent; no submarginal protuberance between ocular and antennal peduncle. Anterolateral angle rounded. Posterior submarginal ridge elevated, sharp, unarmed. Rostrum ( Figure 8 (a,)) about 0.3 times PCL, narrow, distinctly tapering distally in dorsal view, terminating in blunt tip, nearly horizontal; dorsal surface with median granular carina extending between epigastric bulges; surfaces lateral to carina minutely granulate; width at base about 0.4 of distance between anterolateral angles of carapace.

Pterygostomian flap ( Figure 8 (b)) covered with short rows of granules; anterior margin bluntly subtriangular.

Sternum ( Figure 8 (c)) 1.2 times as wide as long, maximum width at sternite 7. Sternite 3 divided into 2 ovate lobes with distinctly sinuous anterior and posterior margins. Sternite 4 2.6 times wider than, and not contiguous to, sternite 3; surface smooth except for scattered granules, with subcircular median depression behind posterior margin of sternite 3; anterolateral margins gently concave, each with granulated ridge. Sternites 5–7 nearly smooth, each side with elevated anterior margin.

Pleon ( Figure 8 (a,,)) unarmed, surfaces of tergites and pleura smooth. Tergites 2–4 each with elevated transverse ridge anteriorly, tergites 2 and 3 each with posterior transverse ridge. Tergites 5 and 6 without transverse ridges, distomedian margin of tergite 6 flattish. Telson ( Figure 8 (e)) 1.3 times as wide as long, composed of 8 calcified plates.

Ocular peduncle ( Figure 8 (a)) short, stout, movable, unarmed. Cornea subglobular, not dilated, weakly pigmented, slightly longer than remaining peduncle, reaching 0.4 length of rostrum.

Antennular article 1 ( Figure 8 (f)) distally armed with 2 strong, well-separated spines, ventrodistal spine larger than dorsodistal spine.

Antennal peduncle ( Figure 8 (f)) overreaching distal corneal margin by half length of article 4; article 1 with small subacute distomesial projection; articles 2–4 unarmed.

Mxp3 ( Figure 8 (g)) ischium 0.8 merus length; dorsal margin sharply ridged, with small distolateral spine, crista dentata consisting of 19 corneous denticles. Merus with 2 spines on ventral margin,distal spine smaller than proximal spine;dorsal margin with strong distal spine.

P1 subequal ( Figure 8 (h)), 3.3–3.4 times PCL, unarmed, covered with numerous coarse granules. Merus somewhat concave on mesial surface; lateral surface with short subdistal ridge. Carpus and chela slightly compressed dorsoventrally. Palm 1.8 times longer than carpus. Fingers 0.9 length of palm, not gaping when closed; cutting edges each with row of small blunt teeth, also with low tooth proximally on dactylus.

P2–4 missing. Epipods absent from P1–4.

Remarks

As discussed above in the Remarks section for M. bengala sp. nov., M. kadal sp. nov. is morphologically similar to M. bengala sp. nov., M. bruta , M. shulerae and M. truculenta . However, M. kadal sp.nov. is distinguished from the other four species by the proportionally shorter antennal peduncle which overreaches the distal corneal margin by half the length of article 4, rather than by at least the full length of article 4 as in the other species.

Munidopsis kadal sp. nov. is morphologically closest to M. shulerae in having the combination of the following characters: the carapace lateral margins are subparallel; the epigastric bulges each have a tuberculate ridge anteriorly; and the rostrum has a middorsal carina. However, the new species differs from M. shulerae in lacking dense short setae along the cutting edges of the P1 finger, in addition to having a proportionally shorter antennal peduncle.

The new species further differs from M. bruta in the dorsal margin of the Mxp3 merus being unarmed exclusive of a strong distal spine, instead of being crenulated or having one or two small spines; and from M. truculenta in the lateral carapace margins being subparallel, rather than divergent posteriorly, and the dorsal surface of the carapace with coarse granules and small tubercles, rather than being distinctly tuberculate, particularly on the branchial region.

Munidopsis kadal sp. nov. and M. bengala sp. nov. are distinguishable by the following characters.

(1) The dorsal surface of the carapace is more strongly uneven and more tuberculate in M. kadal sp. nov. than in M. bengala sp. nov.

(2) The lateral margins of the carapace are subparallel in M. kadal sp. nov., but they are gently divergent posteriorly along the anterior three-fourths in M. bengala sp. nov.

(3) The pair of epigastric bulges on the carapace are each delimited anteriorly by a tuberculate ridge in M. kadal sp. nov., whereas the anterior margin of the epigastric bulges is rounded and such ridge is absent in M. bengala sp. nov.

(4) The rostrum is wider at the base and tapers more strongly in M. kadal sp. nov. than in M. bengala sp. nov. The basal width of the rostrum is about 0.4 and 0.3 of the distance between the anterolateral angles of the carapace in M. kadal sp. nov. and M. bengala sp. nov., respectively.

(5) The Mxp3 merus has a strong dorsodistal spine in M. kadal sp. nov.; the spine is absent in M. bengala sp. nov.

Geographical distribution

So far known only from the type locality, south-eastern Arabian Sea , off Kerala, India, 1018 m depth ( Figure 1 ) .

Figures

Figure 1. Map of India indicating collection locations for the material examined in the present study. 1, Raymunida shraddhanandi sp. nov. and R. vittata Macpherson, 2009; 2, Munidopsis bengala sp. nov.; 3, Munidopsis kadal sp. nov.

Figure 3. Carapace, pleon and cephalic appendages, dorsal view. (a) Raymunida shraddhanandi sp. nov., holotype ♂ (PCL 9.7 mm, CW 8.2 mm), IO/SS/ANO/00141; (b) R. shraddhanandi sp. nov., paratype ♀ (PCL 5.8 mm, CW 4.9 mm), IO/SS/ANO/00140; (c) R. vittata Macpherson, 2009, ♀ (PCL 9.0 mm, CW 7.7 mm), IO/SS/ANO/00142;(d) Munidopsis bengala sp. nov., holotype ♀ (PCL 8.0 mm, CW 7.7 mm), IO/ SS/ANO/00145; (e) M. kadal sp. nov., holotype ♂ (PCL 5.2 mm, CW 4.9 mm), IO/SS/ANO/00146. Scale bars: 2.0 mm.

Figure 8. Munidopsis kadal sp. nov., holotype ♂ (PCL 5.2 mm, CW 4.9 mm), IO/SS/ANO/00146. (a) carapace, pleon and cephalic appendages (dorsal view); (b) carapace (right lateral view); (c) thoracic sternum (ventral view); (d) pleomeres 1–5 (dorsal view); (e) pleomeres 5 and 6 and telson (dorsal view); (f) right eye, antennular peduncle article 1 and antennal peduncle (ventral view); (g) left Mxp3 (lateral view); (h) right P1, dorsal view. Scale bars: a–e, h = 1.0 mm; f, g = 0.5 mm.