Dicranodromia karubar Guinot, 1993

Ng, Peter K. L. & Yang, Chien-Hui, 2021, On two new species of deep-sea carrier crabs (Crustacea, Brachyura, Homolodromiidae, Dicranodromia) from Taiwan and the Philippines, with notes on other Indo-West Pacific species, ZooKeys 1072, pp. 129-165 : 129

publication ID	https://dx.doi.org/10.3897/zookeys.1072.72978
persistent identifier	https://treatment.plazi.org/id/1E5392D8-EC9A-514B-87B4-8A1806EBAC99
treatment provided by	ZooKeys by Pensoft
scientific name	Dicranodromia karubar Guinot, 1993
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Dicranodromia karubar Guinot, 1993 View in CoL

Figures 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11D-F View Figure 11

Dicranodromia karubar Guinot, 1993: 213, figs 15A-C, 16A-D, 25A, B; Ng et al. 2008: 39; Mendoza et al. 2021: 284, fig. 1A, B.

Material examined.

Indonesia: 1 ♂ (28.7 × 34.7 mm), 3 ovigerous ♀♀ (24.8 × 31.5 mm, 27.1 × 33.4 mm, 27.6 × 33.8 mm), station CP39, 8°15.885'S, 109°10.163'E - 8°16.060'S, 109°10.944'E, 528-637 m, substrate partially muddy, plenty of glass sponges, echinoderms, polychaeta, galatheids, fishes, sea anemone, gastropods and bivalves, south of Cilacap, south Java, Indian Ocean, South Java Deep Sea cruise, coll. beam trawl, 30 Mar. 2020 (ZRC 2020.0348); 1 ovigerous GoogleMaps ♀ (30.1 × 35.5 mm), station CP51, 7°04.874'S, 106°25.396'E - 7°05.348'S, 106°25.044'E, 569-657 m, substrate coarse sand, mud and some plastic trash, small crabs, ophiuroids, stalk crinoids, chitons, limpets and sea daisies on fallen bamboo, Pelabuhanratu Bay, south Java, Indian Ocean, South Java Deep Sea cruise, coll. beam trawl, 2 Apr. 2020 (ZRC 2020.0349, COI sequence: OK331336 View Materials ) GoogleMaps .

Remarks.

Mendoza et al. (2021) recently recorded D. karubar from southern Java, over 1000 km from its type locality in the Moluccas. The specimens, however, agree very well with the descriptions and figures of Guinot (1995) and they are clearly conspecific.

Guinot (1995: 215) noted that the rostrum of this species is at most a tubercle, which is in conformity with the present material. The merus, carpus and dactylus were described as unarmed by Guinot (1995), but the P5 propodus actually has one or two spines on the outer surface, which are hard to see as the dense plumose setae obscure them. In some specimens, the P5 dactylus has a prominent spine on the extensor margin (Fig. 10D View Figure 10 ), but as reported by Ng and Naruse (2007), it is absent in others (Fig. 9G, H View Figure 9 ). The form of the exorbital tooth varies to some degree. In the female specimens, the tooth is clearly directed anteriorly (Fig. 8B, C View Figure 8 ) but in the male, it is pointed obliquely laterally (Fig. 10B View Figure 10 ).

The setae on D. karubar are unusual in that they are plumose at the distal part ( Guinot 1995: fig. 16D). When the animals are freshly collected, the setae lock together to form a dense coat, which traps fine mud and completely obscure the carapace and pereiopod surfaces and margins (Fig. 7A View Figure 7 ). After the specimen is cleaned gently with a brush and the sediment removed, the surfaces and margins become more visible with the distal plumose parts no longer meshed together. The margins of the pereiopods, however, are still partially obscured as the setae there are denser (Fig. 7B, C View Figure 7 ). In the form of the setae, D. karubar is most similar to D. baffini from the Indian Ocean, although the tomentum of the latter species is relatively less dense (cf. Padate et al. 2020: fig. 2a).

Dicranodromia karubar can easily be separated from D. baffini by its proportionately broader carapace (Figs 8B View Figure 8 , 10B View Figure 10 ) (versus relatively narrower and longer in D. baffini ; cf. Guinot 1995: fig. 13, Padate et al. 2020: fig. 2a); the antero- and posterolateral margins almost smooth, except sometimes for a few scattered granules (Figs 8B View Figure 8 , 10B View Figure 10 ) (versus lined with granules and spinules in D. baffini ; cf. Guinot 1995: fig. 13, Padate et al. 2020: fig. 2a); and the subdistal lobe on the outer margin of the endopod curved and beak-like (Fig. 11D, E View Figure 11 ) (versus lobe rounded in D. baffini ; cf. Padate et al. 2020: fig. 2g, i). Based on the figures of Gordon (1950), Guinot (1995: fig. 16C) commented that the structure of the spermatheca was different in the two species, but we do not discern any major differences since both species possess an unusual and prominent comma-shaped tubercle on each side of sternite 7, with the spermatheca at the base of this tubercle (Fig. 9J View Figure 9 ). The spermathecal structure in the D. baffini from the Andamans (cf. Padate et al. 2020: fig. 2j) is almost identical to the condition observed in D. karubar (Fig. 9J View Figure 9 ). Alcock and Anderson (1899: 8) described the structure as "sternal grooves of the female end, without tubercles, at the level of the openings of the oviducts", which does not match the description and figures of Gordon (1950: 205, text-fig. 1) and Padate et al. (2020: fig. 2j). As noted by Padate et al. (2020: 3), the condition observed by Alcock and Anderson (1899) may be because their specimen was a juvenile.

Dicranodromia karubar is known thus far only from the Moluccas and eastern part of the Indian Ocean while D. baffini has been recorded from western India, Maldives and Andamans ( Alcock 1899, 1901; Gordon 1950; Padate et al. 2020).

All the females of D. karubar collected from the south Javan cruise were ovigerous, the eggs being bright red in life, in a prominent brood pouch (Fig. 7D View Figure 7 ). One female specimen (27.6 × 33.8 mm, ZRC 2020.0348) had 362 eggs, each about 2.5 mm in diameter.