Munidopsis tuerkayi, Macpherson, Enrique, Beuck, Lydia & Freiwald, Andrè, 2016

Macpherson, Enrique, Beuck, Lydia & Freiwald, Andrè, 2016, Some species of Munidopsis from the Gulf of Mexico, Florida Straits and Caribbean Sea (Decapoda: Munidopsidae), with the description of two new species, Zootaxa 4137 (3), pp. 405-416 : 411-413

Munidopsis tuerkayi n. sp.

( Figs. 3 , 4A , 5 A–B)

Material examined. Holotype. SMF 49249, male, 7.3 mm, Campeche Bank (Gulf of Mexico), 23°49.731’N, 87°10.319’W, 578 m, RV ‘ Maria S. Merian’ MSM 20/4 Station GeoB 163 09-1, BC, 22 March 2012, no sediment collected—associated only with few scleractinian fragments ( Lophelia pertusa ), Munidopsis penescabra and sponges.

Paratype. SMF 49251, male, 7.9 mm, Southwest Florida (Gulf of Mexico), 25°16.256’N, 84°26.805’W, 539 m, RV ‘ Maria S. Merian’ MSM 20/4 Station GeoB 163 47-1-5, ROV dive 8 subsample 4, 29 March 2012, with polynoid polychaete Gorgoniapolynoe caeciliae (Fauvel, 1913) on fan-shaped, current oriented primnoid coral Candidella imbricata (Johnson, 1862) , the latter was attached to apical part of a rock exposure (see also Barnich et al. 2013).

Etymology. Named for our friend and colleague, the late Michael Türkay, for his important contributions to carcinology.

Description. Carapace: Dorsally unarmed, 1.2 times longer than wide; moderately convex from side to side; sparsely covered with short, fine setae and fine striae; cervical groove shallow; epigastric region with short striae. Dorsal margin of orbit oblique, antennal (outer orbital) spine small. Frontal margins oblique; anterolateral spine slightly larger than outer orbital spine. Lateral margins slightly convex; widest at posterior half; unarmed. Rostrum broad, 0.35–0.40 carapace length; trifid distally; apex directed slightly upwards; carinate dorsally; lateral proximal margin almost straight. Pterygostomian flap with short, sparse striae; anterior margin blunt.

Sternum: Longer than wide. Sternite 3 about 0.3 width of sternite 4. Posterior margin of sternite 3 contiguous with anterior margin of sternite 4. Sternites 4–7 successively wider posteriorly, smooth, sparsely setose, unarmed.

Abdomen: Tergites with short, fine, scattered setae, unarmed. Tergites 2–4 with elevated anterior ridge; tergites 2 and 3 with shallow groove behind anterior ridge. Tergites 4 and 5 smooth. Tergite 6 with posterior margin not produced. Telson composed of 8 plates. Uropodal endopod lateral margins setose, unarmed.

Eye: Ocular peduncle unarmed, surface sparsely setose; movable; partially concealed by rostrum. Cornea subglobular, slightly wider than peduncle.

Antennule: Article 1 with 2 distolateral spines, dorsal spine shorter; distomesial margin blunt, slightly dentate.

Antenna: Article 1 with distomesial spine reaching end of article 2, lateral spine much smaller. Article 2 with minute distolateral spine. Article 3 unarmed. Article 4 with lateral triangular projection. Flagellum longer than carapace.

Mxp3: Merus with 2 large spines along flexor margin, proximal larger than distal, with small spine between; small distal spine on extensor margin. Ischium wider than long, with distal flexor and extensor spine. Crista dentata finely denticulate. Dactylus, propodus and carpus unarmed.

P1: Elongate, 2.9–3.0 times carapace length; with tufts of long, simple setae, more numerous on dorsal and mesial margins; section subcylindrical to ovate. Ischium with ventrodistal spine and dorsal spine. Merus with 3 strong, mesial spines; dorsal side with 1 distal spine; lateral margin unarmed; ventromesial margin with 2 proximal spines. Carpus twice longer than high, with 1 distomesial spine. Palm unarmed, about 3 times longer than high and 1.3 times longer than fingers. Fingers unarmed, occlusal margins dentate, apices with interlocking teeth; fixed finger without denticulate carina on distolateral margin.

P2–4: Moderately setose, sparsely with long setae on all articles. P2 1.6–1.8 times carapace length, not exceeding P1. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.9 length of P3 merus), equally broad on P2–4; P2 merus 0.6 carapace length, 3.4 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 3.0 times as long as broad, 1.2 times length of P3 propodus; P4 merus 2.7 times as long as broad, 1.1 times length of P4 propodus; extensor margins each with row of minute spines and moderately strong distal spine; lateral surface unarmed; flexor margins each with small terminal spine. Carpi each with distal spine on extensor margin; lateral surface with rugose crest paralleling extensor margin; flexor distal margins each bluntly angular. Propodi subequal in length, equally broad, and 4.3–4.6 times as long as broad; extensor margins unarmed; flexor margins each with 2–4 slender movable spines. Dactyli subequal in length, 0.6 length of propodi, ending in incurved, strong, sharp spine; flexor margins each with prominent triangular subterminal tooth preceded by 6 or 7 low proximally diminishing teeth, each tooth bearing robust seta; ultimate tooth equidistant between penultimate tooth and dactylar tip.

Epipods absent from pereopods.

Colour in life. Either carapace and abdomen whitish or carapace pale-pinkish (colour resembling that of the Candidella imbricata polyp tissue) with a whitish cross in center and whitish flanks, abdomen whitish with two pale-pink broad longitudinal stripes; P1–4 pale brown. Cornea pale.

Remarks. Munidopsis tuerkayi n. sp. belongs to a group of species sharing a flattened, distally trifid rostrum, unarmed carapace surface, unarmed abdominal tergites and the absence of pereopodal epipods. This group includes M. acuminata Benedict, 1902 [off South Carolina, northwestern Atlantic], M. alcocki Ahyong, 2014 [Indian Ocean, from Madagascar to Bay of Bengal], M. aurantia Lin & Chan, 2011 [ Taiwan], M. kareenae Ahyong, 2013 [ New Zealand], M. modesta Benedict, 1902 [Galapagos Islands], M. nias Ahyong, 2014 [eastern Indian Ocean], M. pubescens Macpherson, 2007 [ Madagascar], M. serricornis ( Loven, 1852) [North Atlantic Ocean] and M. treis Ahyong & Poore, 2004 [southern Australia to New Caledonia including New Zealand]. The closest relative of the new species is M. kareenae . They can be easily distinguished by the following characters:

The flexor margin of the Mxp3 merus has 2 large spines proximally, the proximalmost having a prominent convex lobe on the posterior margin, in M. kareenae . This margin has one proximal and one distal spine, without convex lobes in the new species.

The P1 merus and carpus have rows of well-developed dorsal spines in M. kareenae , whereas these dorsal spines are absent in the new species (only one distal spine in the merus).

The extensor margins of the meri and carpi of P2–3 are prominently spinose in M. kareenae , whereas these margins are serrate (only with a distal spine) in the new species.

The P2–4 propodi are more slender in M. kareenae than in the new species, (length-breadth ratio 6.5–6.7 versus 4.3–4.6).

In the Atlantic Ocean, the closest relative is M. serricornis . However, the new species differs from M. serricornis in lacking spines on the lateral margins of the carapace behind the anterolateral spine. Furthermore, the extensor margin of P2–4 meri each has a row of minute spines distally ending in a moderately strong spine in M. tuerkayi , whereas these spines are well developed in M. serricornis .

Distribution. Only known from the Gulf of Mexico, at 539–578 m water depth.

Figures

FIGURE 3. Munidopsis tuerkayi n. sp., holotype, male, 7.3 mm (SMF 49249). A, carapace and abdomen, dorsal view. B, carapace and abdomen, right lateral view. C, telson. D, sternal plastron. E, left antenna and antennule, ventral view. F, right Mxp 3. G, right P 1. H, right P 2. I, right P 2 dactylus. J, right P 3. K, right P 4. Scale: A – D = 2.0 mm; G, H, J, K = 1 m; E – F, I = 0.5 mm.

FIGURE 5. Munidopsis on host substrate. A, B, Munidopsis tuerkayi n. sp., paratype, male, 7.9 mm (SMF 49251); C, D, Munidopsis serricornis, ovigerous female, 10.1 mm (SMF 49250). A, habitat of sample before collection; fan-shaped Candidella imbricata (Johnson, 1862) colonies attached to rock exposure (copyright MARUM 2012). B, Candidella imbricata sample collected with a multitude of Gorgoniapolynoe caeciliae (Fauvel, 1913) kept in sea-water with in-situ ambient temperature; note the pale-pink colour patterns on the whitish carapace and abdomen resembling the octocoral polyp colour. C, habitat of sample before collection; live Enallopsammia profunda (Pourtalès, 1867) colony on rock exposure (copyright MARUM 2012). D, close-up of sample; note the pale-orange colour patterns of the carapace and abdomen, resembling the colour of the Enallopsammia profunda polyp tissue.

FIGURE 4. A, Munidopsis tuerkayi n. sp., holotype (SMF 49249). B, M. penescabra (SMF 49254). C, M. spinifer (SMF 49252). Scale: 5 mm.