Zarenkolambrus epibranchialis (Zarenkov, 1990) Zarenkov, 1990

Mclay, Colin L., 2009, Revision of the crab genus Garthambrus Ng, 1996, with the description of two new genera and discussion of the status of Tutankhamen Rathbun, 1925 (Crustacea: Brachyura: Parthenopidae), Zootaxa 2122, pp. 1-50 : 38

Zarenkolambrus epibranchialis (Zarenkov, 1990) comb. nov.

( Figs 18 C,D, 20)

Heterocrypta epibranchialis Zarenkov, 1990: 232 , fig. 10. – Parin et al. 1997: 163 (list).

Type material. SYNTYPES: 2 males CL 4.8 mm, CL 5.0 mm, Southeast Pacific Ocean. Near Sala y Gómez and Utes seamounts, stn 2003, 330– 350 m, RV Professor Shtokman; 1 damaged specimen, Igolnaya Seamount, stn 2007, 290– 310 m, RV Professor Shtokman: Data after Zarenkov (1990). None of these specimens were examined.

Diagnosis. Carapace finely granular, not spinose, without deep lacunae; supra-orbital region without spines. Tubercles on protogastric, mesogastric, epibranchial, mesobranchial and cardiac regions not fusing together to form smooth ridges or plates. Rostrum long, about one-quarter carapace length. Epibranchial margin teeth flat, edges irregular. Sub-orbital spine produced, tip extending beyond anterior outer corner of antennal article 2. Outer margins of cheliped merus and carpus not tuberculate, appearing entire. P5 upper margin of merus, carpus and propodus dentate.

Distribution. Southeastern Pacific (290–350 m) and Nazca and Sala y Gómez submarine ridges, Eastern Pacific (Zarenkov, 1990).

Remarks. The diagnostic features, originally given in Russian by Zarenkov (1990) and translated by A. Anker, are as follows: “whole body surface finely granular. Rostrum triangular, apex rounded, sides slightly concave. Posterior edge of orbits with small notch. Border of branchiostegal region with 6–8 irregular, flattened teeth. Lateral border of carapace continued by somewhat rounded process. Posterior epibranchial border of carapace separated from posterior border by some teeth. Dorsal surface of carapace inflated in the middle and bears some feebly marked epibranchial keels. Telson triangular, abdominal segment 6 with large/ tubercle in middle of anterior border. Shape of sixth segment trapezoidal. Eye stalk minutely tuberculate. Basal article of antenna with sub-terminal process. Deep depression of antennule not completely separated from orbit by rostral process.

Third maxilliped ischium and merus granular, anterior borders depressed. Lateral anterior part of merus slightly expanded.

Cheliped cutting edges not regular. Upper surface of dactylus with teeth and large process near articulation. Three flattened teeth on upper surface of propodus with large process near carpus. Dactylus also with process. Cheliped merus with one shallow process (tooth), with small process (tooth) in the middle, also four on the inner side.

Meri of P2–P5, have 5–7 granules/teeth on anterior margin. Same kind of teeth also present on posterior margin of P4 and P5. P2 and P3 without teeth on posterior margin. Lower surface of carpus smooth but upper surface granular (P2–P5). Propodus of P2–P5 granular on both margins. Dactylus straight; surface smooth.”

It is clear from the text and the illustration (Zarenkov, 1990: 233, fig. 10) that this species does not belongs in the genus Heterocrypta Stimpson, 1871 , or similar genera like Cryptopodia H. Milne Edwards, 1834 , or Furtipodia Tan & Ng, 2003 . It does not resemble any of these genera because of the differences in carapace shape. The posterior lateral portion of the carapace of Z. epibranchialis is clearly not expanded to cover the ambulatory legs as in Cryptopodia . In addition, Z. epibranchialis has prominently produced lateral teeth, which are absent in Heterocrypta , Cryptopodia and Furtipodia .

Although we did not examine any specimens of this species, illustrations of this species, although somewhat schematic, show that it has several unique features. Its most prominent feature is the long rostrum, which is about one quarter of the entire carapace length. We believe that the long rostrum is more apparent than real and is the result of the orientation used by Zarenkov (1990) for his illustration ( Fig. 10 ). The other Zarenkolambrus species, Z. minutus has a much shorter rostrum. The gonopods shown in Fig. 6 E & F are probably those of an immature male because the G2 flagellum is not twisted, so the exact adult gonopods are yet to be determined. Zarenkolambrus epibranchialis is only known from two small males (CL 4.8–5.0 mm) and one damaged specimen.

Figures

FIGURE 6. Gonopods. Garthambrus darthvaderi sp. nov.: A, B, holotype, male 19.9 x 14.0 mm (MNHN), New Caledonia, BIOCAL, stn DW 44, 22 ° 47 ’ S, 167 ° 14 ’ E, 440 – 450 m, 30 Aug 1985. — Garthambrus lacunosus (Rathbun, 1906): C, D, holotype, male 30.9 x 21.8 mm (USNM 29842), Hawaiian Is, west coast of Hawaii, Kawaihae. — Garthambrus posidon Ng, 1996: E, F, male 35.3 x 23.8 mm (MNHN), Madagascar; A, C, left G 1; B, D, left G 2; E, right G 1; F, right G 2. Scale bar = 1 mm.

FIGURE 10. Garthambrus cidaris (Garth & Davie, 1995): A, holotype, female 52.8 x 36.1 mm (QM W 16086), Australia, northeast Queensland. — Garthambrus complanatus (Rathbun, 1906): B, lectotype, male 17.3 x 12.7 mm (USNM 29845 a), Hawaiian Is, Kauai.

FIGURE 18. Gonopods. Zarenkolambrus minutus sp. nov.: A, B, holotype male 6.2 x 5.1 mm (MNHN), French Polynesia, Austral Is, Raevavae, SMCB, stn D 66, 23 ° 50.54 ʹS 147 ° 42.73 ʹW, 400 m, 3 Dec. 1990 (scale bar = 1 mm). — Zarenkolambrus epibranchialis (Zarenkov, 1990): C, D, male CL 5.0 mm, eastern Pacific Ocean, near Sala y Gómez, Ignolnaya, RV Professor Stockman, stn 2007, 6 – 7 May 1987 (after Zarenkov 1990: fig. 10) (scale bar not available). A left G 1, B, left G 2; C, right G 1; D, right G 2.