Paramaya mulli, Ng & Prema & Ravichandran, 2018

Ng, Peter K. L., Prema, M. & Ravichandran, S., 2018, A new species of deep-water spider crab of the genus Paramaya De Haan, 1837 from the Bay of Bengal, India (Crustacea, Brachyura, Majidae), ZooKeys 769, pp. 77-88 : 78-83

publication ID	https://dx.doi.org/10.3897/zookeys.769.26152
publication LSID	lsid:zoobank.org:pub:B403C281-6BE4-40D1-972D-DC351B7ACD44
persistent identifier	https://treatment.plazi.org/id/694A5779-FC41-4105-B536-9FB7DC23D65D
taxon LSID	lsid:zoobank.org:act:694A5779-FC41-4105-B536-9FB7DC23D65D
treatment provided by	ZooKeys by Pensoft
scientific name	Paramaya mulli
status	sp. n.

Treatment

Paramaya mulli sp. n. Figs 1 View Figure 1 , 2A-C View Figure 2 , 3A-C View Figure 3 , 4A, B View Figure 4 , 5A-D, H View Figure 5 , 6 View Figure 6 , 7 View Figure 7

Maia spinigera - Alcock 1895: 239; Alcock and Anderson 1898: pl. 34, fig. 3.

Paramaya mulli Maja spinigera " - Ng and Richer de Forges 2015: 156, fig. 22B-D.

Paramaya mulli Non Pisa (Paramaya) spinigera De Haan, 1837.

Material examined.

Holotype: male (70.4 × 61.4 mm) (CASAU), Pazhayar fish landing centre, facing Bay of Bengal, Tamil Nadu, India, 11°21'11.5"N, 79°45'26.3"E, from trawls, coll. M. Prema and S. Ravichandran, 7 February 2018 GoogleMaps . Paratype: 1 female (40.0 × 33.5 mm) (CASAU), same data as holotype GoogleMaps .

Comparative material examined.

Paramaya spinigera (De Haan, 1837): 7 males (85.0 × 66.4 mm, 78.2 × 62.1 mm, 73.6 × 55.3 mm, 68.3 × 53.4 mm, 73.8 × 58.4 mm, 62.8 × 49.0 mm, 72.8 × 57.3 mm), 1 ovigerous female (63.0 × 48.6 mm) (ZRC 1999.738), Longtong , near Keelung, northern Taiwan, in tangle nets for lobsters, coll. S-H Wu, May 1999. For other material of Paramaya species, see Ng and Richer de Forges (2015) .

Diagnosis.

Pseudorostral horns relatively short (Figs 2A View Figure 2 , 3A, B View Figure 3 ); hepatic, lateral and branchial spines long; median row with 5 spines: 3 gastric, 1 cardiac, 1 intestinal; 2 spines on posterior carapace margin (Figs 2A View Figure 2 , 3A View Figure 3 ); adult branchial region distinctly swollen (Fig. 3A, C View Figure 3 ); intercalated tooth on carapace relatively broad (Figs 3B View Figure 3 , 4A, B View Figure 4 ); epistome quadrate (Fig. 5A, B View Figure 5 ); surface of thoracic sternum not prominently setose, with numerous prominent rounded granules (Figs 5C View Figure 5 , 6B View Figure 6 ); chela of adult male with distinct carina on dorsal and ventral margins (Figs 2A View Figure 2 , 6D View Figure 6 ); ambulatory meri in adult males relatively slender, long (Figs 2A View Figure 2 , 5D View Figure 5 ); G1 gently curved, dorsal projection on the sub distal part low, tip distinctly rounded (Fig. 7A-C View Figure 7 ).

Colour. Freshly obtained specimens have the dorsal surfaces orangish-red, with red and white bands on ambulatory legs; chelipeds yellowish-orange with white fingers; ventral surfaces white with patches of orange (Fig. 1 View Figure 1 ).

Etymology.

The species is named after the famous Mulli plant in Tamil mythology, from the classic poetic work Kurunthogai. Mulli is a coastal plant ( Spinifex littoreus (Burm.f.) Merr., family Poaceae ) with very sharp spines (mull is the Tamil word for spiny), a character shared with the present species. The name is used as a noun in apposition.

Remarks.

Compared to P. spinigera , the branchial region of adult male P. mulli sp. n. is more swollen (Fig. 3A, C View Figure 3 ) (versus gently convex in P. spinigera ; Fig. 3D, F View Figure 3 ); the intercalated tooth on the carapace is relatively broader (Figs 3B View Figure 3 , 4A, B View Figure 4 ) (versus more acutely triangular in P. spinigera ; Figs 3E View Figure 3 , 4C, D View Figure 4 ); the epistome is more quadrate (Fig. 5A, B View Figure 5 ) (versus more transversely rectangular in P. spinigera ; Fig. 5E, F View Figure 5 ); the surface of the male thoracic sternum, especially the areas adjacent to the sternopleonal cavity is distinctly granulated with scattered setae (Fig. 5C View Figure 5 ) (versus surfaces weakly granulate with dense setae in P. spinigera ; Fig. 5G View Figure 5 ); and the G1 has the dorsal projection on the subdistal part relatively small with the tip more prominently rounded (Fig. 7A-C View Figure 7 ) (versus dorsal projection on the subdistal part more developed with the tip gently tapering in P. spinigera ; Ng and Richer de Forges 2015: fig. 23A-C).

There is variation in the proportions of the ambulatory legs of Paramaya species. In the series of specimens of P. spinigera on hand, females generally have relatively shorter ambulatory legs compared to males. In addition, for each sex, smaller specimens have proportionately shorter and stouter legs (Fig. 5I View Figure 5 ) compared to larger ones (Fig. 5J View Figure 5 ). When comparing the holotype male P. mulli sp. n. (70.4 × 61.4 mm, CASAU) with a similar size male of P. spinigera from Taiwan (73.6 × 55.3 mm, ZRC 1999.738), the merus, propodus and dactylus of P. mulli sp. n. (Fig. 5D View Figure 5 ) is significantly more slender and longer than that of P. spinigera (Fig. 5I View Figure 5 ). In larger male specimens of P. spinigera from Taiwan (85.0 × 66.4 mm, ZRC 1999.738), the merus is proportionately longer but is still relatively stouter (Fig. 5J View Figure 5 ). Females of both species have relatively shorter and stouter ambulatory legs compared to males (Fig. 5H View Figure 5 ).

Ng and Richer de Forges (2015: 156) noted that the specimen mentioned and figured by Alcock (1895) and Alcock and Anderson (1898) as " P. spinigera " has short ambulatory meri, but this is probably because this specimen was small; and the larger specimen from Sri Lanka they examined a photograph has proportionately longer ambulatory legs. As discussed above, the proportions of the ambulatory meri is clearly correlated with size. Noteworthy is that the Sri Lankan specimen also has relatively more inflated branchial regions, and as such, is almost certainly conspecific with what is described here as P. mulli sp. n.

The distinctly granulated thoracic sternum of P. mulli sp. n. (Fig. 5C View Figure 5 ) allies the species with P. ouch ( Ng and Richer de Forges 2015: fig. 50B), but in P. ouch , the branchial region is not distinctly swollen, and the pseudorostral and carapace spines are proportionately longer across all size ranges in both sexes (cf. Ng and Richer de Forges 2015: figs 21E, F, 37B) (versus branchial regions more swollen and the spines are proportionately shorter in P. mulli sp. n.; Figs 2A View Figure 2 , 3A-C View Figure 3 , 6E View Figure 6 ). In addition, the distal part of the G1 in P. ouch is more strongly curved ( Ng and Richer de Forges 2015: fig. 23D) with the dorsal projection on the subdistal part prominent and the tip is relatively more angular ( Ng and Richer de Forges 2015: fig. 23E, F) (versus distal part of G1 less curved with the dorsal projection low and tip rounded in P. mulli sp. n.; Fig. 7A-C View Figure 7 ). Compared to P. mulli sp. n., P. coccinea has proportionately longer pseudorostral and carapace spines with the branchial region not distinctly swollen ( Ng and Richer de Forges 2015: figs 22A, 37C), the male thoracic sternum is almost smooth with the granules low ( Ng and Richer de Forges 2015: fig. 50C) and the dorsal projection on the subdistal part of the G1 is prominent with the tip relatively more angular ( Ng and Richer de Forges 2015: fig. 23H, I) (cf. pseudorostral and carapace spines proportionately shorter, the male thoracic sternum is distinctly granulated and the dorsal projection on the G1 subdistal part is low with the tip rounded; Figs 2A View Figure 2 , 3A-C View Figure 3 , 5C View Figure 5 , 6E View Figure 6 , 7A-C View Figure 7 ). In addition, even though the holotype male and only known specimen of P. coccinea is about the same size as the holotype male of P. mulli sp. n., the ambulatory meri are proportionately much longer (cf. Ng and Richer de Forges 2015: figs 22A, 70B) (versus distinctly shorter in P. mulli sp. n.; Figs 2A View Figure 2 , 5D View Figure 5 ).

Like other Paramaya species, the preferred habitat of P. mulli sp. n. is probably relatively steep and rocky areas that are difficult to sample except with tangle nets (see Ng et al. 2009, Mendoza et al. 2010). As such, normal fishery operations using trawls are less likely to obtain them and could explain their apparent rarity in Indian waters.