Munidopsis hendrickxi, Rodríguez-Flores & Seid & Rouse & Giribet, 2023

Rodríguez-Flores, Paula C., Seid, Charlotte A., Rouse, Greg W. & Giribet, Gonzalo, 2023, Cosmopolitan abyssal lineages? A systematic study of East Pacific deep-sea squat lobsters (Decapoda: Galatheoidea: Munidopsidae), Invertebrate Systematics 37 (1), pp. 14-60 : 36-39

Munidopsis hendrickxi sp. nov.

( Fig. 10 c, d , 11 b, e , 13 a–k .)

ZooBank: urn:lsid:zoobank.org:act:87A1B63B-878C-48EA-83DC-5B569 0E0A7E6

Material examined

Holotype. USA: California, E/V Nautilus, ROV Hercules dive H1795, Stn NA117-012-01-B-MCZ: 14.x.2019, 35.51857°N, 122.63877°W, 3188 m: 1 M 9.1 mm ( MCZ IZ-153106 ).

Etymology

Named after Michel Hendrickx, crustacean researcher at the Universidad Autonoma of Mexico, in recognition of dedication to the study of squat lobsters and other crustaceans from the Americas.

Diagnosis

Carapace dorsally covered by denticulate tubercles and scales, with dorsal deep furrows and rugae, cervical grooves distinct. Rostrum narrowly triangular, lateral margins subparallel, unarmed. Frontal margins slightly concave. Orbit slightly excavated, outer orbital angle with a blunt lobe. Anterolateral angle armed with a spine. Branchial margin unarmed. Abdominal somites unarmed. Telson divided into 7 plates. Sternite 3 anterolaterally produced, anterior margin serrated with a median acute lobe, sternite 4 narrowly subtriangular. Eyes unarmed, immovable, epistomial spine present. Article 1 of antennule with well-developed dorsolateral and distolateral spines, distolateral double. Article 1 of antenna with distomesial blunt process, distolateral with denticules. Mxp3 merus subrhomboidal in lateral view. P1 moderately slender, with some spines, fixed finger without denticulate carina on distolateral margin. P2–4 moderately slender, unarmed; meri carinated, dactyli slender, curving, flexor margin with minute teeth along all margins decreasing proximally. Epipods present on P1–2.

Description

Carapace

Slightly longer than broad, widest at midlength; moderately convex from side to side. Dorsal surface covered by denticulate tubercles and scales, each tubercle and scale with a few short setae and some long, thick setae; hepatic and anterior branchial areas with scales and some acute tubercles; posterior cardiac and intestinal region covered by larger scales. Regions well delineated by furrows including distinct anterior and posterior cervical grooves. Gastric region slightly elevated. Posterior margin preceded by elevated ridge. Rostrum narrowly triangular, directed downwards slightly, distally covered with tubercles on lateral margins; dorsal surface longitudinally carinate, with granules along midline, 0.3× as long as remaining carapace length, 1.7× longer than broad, 1.4× as long as broad. Frontal margin slightly concave behind ocular peduncle, outer orbital angle produced into blunt lobe above antennal peduncle, outer orbital spine and process (antennal spine) absent. Lateral margins straight; anterolateral spine well developed; anterior branchial margin with 2–3 small spines. Pterygostomian flap surface covered by granules and scales, anterior margin blunt, unarmed.

Sternum

As long as broad, maximum width at sternites 6 and 7. Sternite 3 broad, 2.6× wider than long, anterolaterally produced, anterior margin serrated with a median acute lobe. Sternite 4 narrowly elongate anteriorly; surface depressed in midline, smooth; greatest width 2.5× that of sternite 3 and 1.6× times wider than long.

Abdomen

Unarmed; tergites 2–3 with 2 elevated transverse ridges, lateral parts of dorsal surfaces smooth; tergites 4–6 lacking posterior ridge; tergite 6 with weakly produced posterolateral lobes and nearly transverse posteromedian margin. Telson composed of 7 plates; 1.3× as wide as long.

Eye

Eyestalk immovable; peduncle short and fixed, shorter than cornea length, wider than cornea width; cornea globular; lateral surface contiguous to small epistomial spine, ventral to frontal margin.

Antennule

Article 1 of peduncle with subequal dorsolateral and distolateral spines, distodorsal spine double; distomesial margin with spine distinct, slightly dentate.

Antenna

Peduncle exceeding eye; article 1 with distomesial blunt process, distolateral process with denticles. Article 2 with well-developed distolateral spine, distomesial surface with denticles. Article 3 with distomesial spine well-developed, distolateral angle with denticles. Article 4 unarmed. Flagellum longer than carapace.

Mxp3

Merus with 3 large spines along flexor margin, proximal larger; 2 small distal spines on extensor margin. Ischium as long as merus measured on extensor margin, with distal flexor and extensor spines. Crista dentata finely denticulate. Dactylus, propodus and carpus unarmed.

P1

Moderately slender, covered by denticles and scales, and fine, long setae, 1.9× longer than carapace. Merus 1.8× carpus length, with rows of spines on mesial, lateral margins and some distal stout spines. Carpus 1.5× longer than broad, with rows of spines on mesial, lateral margins and some distal stout spines. Palm unarmed, stout, slightly longer than carpus, 1.2× longer than broad. Fingers unarmed, 0.9× longer than palm, opposing margins straight, not gaping, spooned, fixed finger without denticulate carina on distolateral margin.

P2–4

Moderately slender, covered by denticles, devoid of setae, cylindrical in cross-section, slightly decreasing in size posteriorly. P2 merus moderately slender, 0.5× carapace length, nearly 3.5× longer than high and 1.2× length of P2 propodus. P2–4 meri decreasing in length posteriorly (P3 merus 0.9× length of P2 merus, P4 merus 0.8× length of P3 merus); extensor margin of P2–4 meri carinate, with denticles along entire border, distal part flattish ending in thick spine; flexor margin denticulate, distal spine strong; carpi with one thick distal spine on extensor margin, granulated carina along lateral side; P2–4 propodi 5.0–6.0 times as long as high, trianguloid in cross-section, armed with numerous denticles on flexor and extensor margins, and dorsal and ventral surface; dactyli 0.5–0.6× length of propodi; distal claw short, moderately curved; flexor margin distally curved, with 6–9 minute teeth only at distal-half margin, decreasing in size proximally, ultimate tooth at midlength between penultimate tooth and dactylar angle.

Epipods

Present on P1–2.

Colouration

Body light orange, whitish eyes.

Distribution

California, at ~3188-m depth.

Genetic data

COI, 16S rRNA and 28S rRNA.

Remarks

Munidopsis hendrickxi sp. nov. belongs to the group of species with the dorsal carapace surface covered in tubercles, granules or denticles, lateral margins of the carapace unarmed, rostrum triangular, frontal margin concave behind the ocular peduncle, eyes with the ocular peduncle short and fixed, lacking an eye-spine and the telson composed of 7–8 plates. The new species morphologically resembles Munidopsis tuberosa Osawa, Lin & Chan, 2008 from southwestern Taiwan and the South China Sea, and M. dispar from the Mariana Trench. However, the new species can be easily distinguished from the other by the following characters:

• The new species has a small spine on the anterolateral margin of the carapace, whereas this margin is unarmed in the other species.

• The new species has different tuberculation in the gastric area (denticles) from that in the cardiac area (long scales) whereas the carapace ornamentation is homogeneous in the other species.

• The new species has epipods on P1–2, whereas epipods are absent from the pereopods in M. dispar and present on P1–3 in M. tuberosa .

The new species and M. dispar diverge on 11.6–12.8% for COI. Unfortunately, there are no molecular data available for M. tuberosa .

Figures

Fig. 10. In situ images. (a, b) Munidopsis girguisi sp. nov., California, dive S0449, SCB-236 (SIO- BIC C14553). (c, d) Munidopsis hendrickxi sp. nov., California, Stn NA117-012-01-B-MCZ, holotype (MCZ IZ-153106). (e, f) Munidopsis similis Smith, 1885, Costa Rica, dive S0230 S3 (SIO-BIC C13964). (g–h) Costa Rica, dive S0213. (g) Munidopsis girguisi sp. nov. (SIO-BIC C13897). (h) Munidopsis cortesi sp. nov., holotype (MZUCR 3761-01). Photo credits: ROV SuBastian/ Schmidt Ocean Institute (a, b, e–h) and Nautilus Live Ocean Exploration Trust (c, d).

Fig. 11. Three-dimensional renderings of Micro-computed tomography X-ray images. (a, d) Munidopsis girguisi sp. nov., M 18 mm, holotype (MCZ IZ-73856). (b, e) Munidopsis hendrickxi sp. nov., M 9.1 mm, holotype (MCZ IZ-153106). (c, e) Munidopsis cortesi sp. nov., ov. F 5.2 mm, holotype (MZUCR 3761-01). Three-dimensional reconstructions available from MCZbase.

Fig. 13. Line diagrams of Munidopsis hendrickxi sp. nov., 1 M 9.1 mm, holotype (MCZ IZ-153106), California. (a) Carapace and abdomen, dorsal view. (b) Carapace and abdomen, lateral view. (c) Sternal plastron. (d) Telson. (e) Cephalic region, showing antennular and antennal peduncles, ventral view. (f) Left Mxp3, lateral view. (g) Right P1, dorsal view. (h) Right P2, lateral view. (i) Right P3, lateral view. (j) Right P4, lateral view. (k) Right P4 dactyli, lateral view. Scale bars: 1 mm.