Munidopsis bengala, 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 : 1830-1834

Munidopsis bengala sp. nov.

( Figures 3 (d), 3)

urn:lsid:zoobank.org:act:EC51F9A5-0565-4502-A2C0-2D40A3794D48

Type material

Holotype. India • ♀ (PCL 8.0 mm, CW 7.7 mm); south-western Bay of Bengal, off Tranquebar , Tamil Nadu; FORVSS stn. 346, leg 1–03; 11.03°N, 80.26°E; 524 m depth; naturalist’s dredge; 5 December 2015; Chippy Khader leg; CMLRE IO /SS/ANO/00145.

Type locality

India: South-western Bay of Bengal , off Tranquebar, Tamil Nadu; 11.03°N, 80.26°E; 524 m depth .

Etymology

The species name is derived from the type locality, the Bay of Bengal.

Diagnosis

Anoplonotus group. Carapace (exclusive of rostrum) dorsally uneven, covered with small, unevenly scattered granules; epigastric bulges blunt, posterior cardiac region narrowly triangular; lateral margins gently diverging posteriorly in anterior three-fourths length, unarmed, each with rounded anterolateral angle. Rostrum narrowly subtriangular, gently deflexed ventrally, with mid-dorsal granular carina extending nearly to epigastric region, lateral margins gently tapering; width at base about 0.3 of distance between anterolateral angles of carapace. Thoracic sternite 4 broad, 2.8 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 each with posterior transverse ridge. No eye spines. Antennular peduncle article 1 with 2 strong distal spines, ventrodistal spine larger than dorsodistal spine. Antennal peduncle overreaching distal corneal margin by combined length of articles 3 and 4, all articles unarmed. Mxp3 with 3 ventral spines, distalmost smallest; dorsal margin distally with small blunt projection. Epipods absent from P1–4.

Description of holotype

Carapace ( Figures 3 (d), 3(a, 3)) (exclusive of rostrum) quadrangular in general outline, 1.1 times as long as wide; lateral margins gently diverging posteriorly in anterior threefourths length and subparallel on posterior one-fourth. Dorsal surface with regions well delineated by deep depressions, uneven in lateral view, unarmed, covered with small, unevenly scattered granules. Hepatic region not elevated. Gastric region strongly convex, with pair of blunt epigastric bulges. Cervical grooves deep. Cardiac region subdivided into anterior and posterior parts by deep transverse groove; posterior part narrowly 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 behind antennal peduncle; antennal spine absent; no submarginal protuberance between ocular and antennal peduncle. Anterolateral angle rounded. Posterior submarginal ridge elevated, sharp, unarmed. Rostrum ( Figure 7 (a,)) 0.3 times PCL, narrow, gently tapering distally in dorsal view, terminating in blunt tip, gently deflexed ventrally; dorsal surface with median granular carina extending nearly to epigastric region; surfaces lateral to carina minutely granulate; width at base about 0.3 of distance between anterolateral angles of carapace.

Pterygostomian flap ( Figure 7 (b)) covered with short rows of granules; anterior margin bluntly subtriangular.

Sternum ( Figure 7 (c)) 1.1 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 2.8 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 and 6 nearly smooth, each side with elevated anterior margin.

Pleon ( Figure 7 (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 7 (e)) about 1.4 times as wide as long, composed of 8 calcified plates.

Ocular peduncle ( Figure 7 (a)) short, stout, movable, unarmed. Cornea subglobular, not dilated, weakly pigmented, slightly longer than remaining peduncle, reaching 0.4 length of rostrum.

Antennular peduncle article 1 ( Figure 7 (f)) distally armed with 2 strong, well separated spines, ventrodistal spine larger than dorsodistal spine.

Antennal peduncle ( Figure 7 (f)) overreaching distal corneal margin by combined length of articles 3 and 4; article 1 wider than articles 2–4, distomesial projection indistinct, rounded; articles 2–4 unarmed.

Mxp3 ( Figure 7 (g)) ischium 0.7 merus length; dorsal margin sharply ridged, with small distal spine, crista dentata consisting of 24 corneous denticles. Merus with 3 blunt spines on ventral margin, distalmost smallest; dorsal margin unarmed, but with small blunt projection distally.

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

Remarks

Among the Anoplonotus group of the genus Munidopsis (see Ahyong et al. 2011; VázquezBader et al. 2014), M. bengala sp. nov. and M. kadal sp. nov., described later in this paper, are similar to M. bruta ( Taiwan, Philippines, Indonesia, Papua New Guinea and Solomon Islands, 329–1203 m depths), M. shulerae (Gulf of Mexico and western Caribbean off the Mexican coast of Yucatan, 320–787 m depths) and M. truculenta (off Congo, Africa, 800– 900 m depth) in having the dorsal surface of carapace with a pair of blunt bulges on the epigastric region and entirely covered with coarse granules or small tubercles, the frontal margins of the carapace gently convex, and the absence of an anterolateral spine on each side of the carapace. Furthermore, the presence of a distinct mid-dorsal carina on the rostrum may link M. bengala sp. nov. and M. kadal sp. nov. more closely to M. shulerae than to M. bruta and M. truculenta . Meanwhile, M. bengala sp. nov. resembles M. truculenta rather than M. bruta and M. shulerae in that the carapace lateral margins are gently divergent posteriorly in the anterior three-fourths; the lateral margins are subparallel in M. bruta and M. shulerae as well as in M. kadal sp. nov. Furthermore, M. bengala sp. nov. is distinctive in lacking a dorsodistal spine on the Mxp3 merus; the spine is present in the latter three species.

In addition, M. bengala sp. nov. is distinguished from M. bruta , M. shulerae and M. truculenta by the following characters. From M. bruta (see Macpherson 2007; Osawa et al. 2013):

1.The antennal peduncle overreaches the corneal distal margin by the combined length of the article 3 and 4 vs only by the length of article 4 in M. bruta .

2.The Mxp3 merus is unarmed on the dorsal margin, whereas it is crenulated or has one or two small spines on the dorsal margin in addition to a strong dorsodistal spine in M. bruta .

From M. shulerae (see Vázquez-Bader et al. 2014):

1.The epigastric bulges of the carapace are rounded on the anterior margins, vs being each delimited anteriorly by a semi-circular tuberculate ridge in M. shulerae .

2.The mid-dorsal carina of the rostrum extends nearly to the epigastric carapace region, whereas it continues as a row of small tubercles between the epigastric bulges in M. shulerae .

From M. truculenta (see Macpherson and Segonzac 2005):

1.The dorsal surface of the carapace is coarsely granular, rather tuberculate, particularly on the branchial region, as in M. truculenta .

The characters that distinguish between M. bengala sp. nov. and M. kadal sp. nov. are discussed below under the Remarks on the latter new species.

Geographical distribution

So far known only from south-western Bay of Bengal, off Tamil Nadu, India, 524 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 7. Munidopsis bengala sp. nov., holotype ♀ (PCL 8.0 mm, CW 7.7 mm), IO/SS/ANO/00145. (a) carapace, pleon and cephalic appendages (dorsal view); (b) carapace and pleon (right lateral view); (c) thoracic sternum (ventral view); (d) pleomeres 1–5 (dorsal view); (e) pleomeres 5 and 6 and telson (dorsal view); (f) left eyes, antennular peduncle article 1 and antennal peduncle (ventral view); (g) left Mxp3 (lateral view). Scale bars: a, b, d = 2.0 mm; c, e–g = 1.0 mm.