Scyramathia hertwigi Doflein, in Chun, 1900

Lee, Bee Yan, Richer De Forges, Bertrand & Ng, Peter K. L., 2020, Revision of the deep-water spider crab genus, Scyramathia A. Milne-Edwards, 1880, with the description of a new species from the Mediterranean and notes on Rochinia A. Milne-Edwards, 1875, and Anamathia Smith, 1885 (Crustacea, Decapoda, Brachyura, Epialtidae), Zoosystematics and Evolution 96 (2), pp. 537-569 : 537

Scyramathia hertwigi Doflein, in Chun, 1900 Figs 10A-C , 14C, D , 15A-D

Scyramathia Hertwigi : Doflein, in Chun 1900: 172 (fig.); Doflein, in Chun 1902-1903: 172 (fig.).

Scyramathia Hertwigi Doflein, 1904: 81-84, pl. 27 fig. 3, pl. 28 fig. 1 (type locality: off Cape Point and on Agulhas Bank).

Scyramathia hertwigi : Stebbing 1902: 7, pl. 6; Stebbing 1905: 25; Stebbing 1910: 289; Barnard 1950: 50, 51, fig. 11b, c; Low et al. 2017: 116, fig. 2A, tables 2, 3.

Rochinia carpenteri : Monod 1956: 32 (list), 515. [not Amathia carpenteri Norman, in Thomson 1873].

Rochinia hertwigi : Serène and Lohavanijaya 1973: 56 (key); MacPherson 1983: 32-35, figs 19, 20a-c; Griffin and Tranter 1986: 175 (key), 180; Casadío et al. 2005: 159 (list); Ng and Richer de Forges 2007: 62 (list); Ng et al. 2008: 105 (list); Tavares and Santana 2018: 223 (list); Griffiths et al. 2018: 199.

Materials examined.

Lectotype: ♂ (33.7 × 27.0 mm) ( ZMB 13699), Atlantic, South Atlantic Ocean, Agulhasstrom [= Agulhas current], coll. Deutsche Tiefsee Expedition, 2 November 1898. Paralectotypes: 3 ♂♂ (24.7 × 19.0 mm, 23.6 × 17.7 mm, 18.7 × 13.7 mm), 2 ♀♀ (28.3 × 22.6 mm, 26.4 × 20.2 mm) ( ZMB 13700), stn 103, Agulhasstrom [= Agulhas current], 500 m, coll. Deutsche Tiefsee Expedition, 2 November 1898; 8 ♂♂ (2 largest: 22.8 × 17.9 mm, 21.6 × 16.5 mm; 2 smallest: 16.2 × 12.3 mm, 16.0 × 11.9 mm), 2 ovigerous ♀♀ (25.9 × 20.5 mm, 24.3 × 19.2 mm), 8 ♀♀ (2 largest: 25.1 × 19.4 mm, 22.6 × 17.3 mm; 2 smallest: 20.1 × 15.2 mm, 14.3 × 10.3 mm) ( SMF 23085), stn 103, Atlantic, South Atlantic, Agulhasstrom [= Agulhas current], 35°10'S, 23°2'E, 500 m, coll. FS ‘Valdivia”, 2 November 1898. Other material: South Africa • 1 ♂ (29.2 × 22.9 mm) ( SAM-A39580), west grounds, I + J trawls, coll. UCT Ecological Survey, 22 November 1946; 2 ♂♂ (33.2 × 27.7 mm, 31.9 × 27.1 mm) ( SAM-A47887), west coast, 333 m, coll. 17 January 2007; 1 ♂ (19.0 × 14.2 mm), 1 ovigerous ♀ (34.4 × 27.1 mm) ( SAM-A12149), West of Slangkop, Cape Peninsula, 457 m, coll. P Henry, 16 February 1965; 1 ♂ (47.0 × 38.0 mm) ( SAM-A40027), stn A10121-082-035-4197, 34°36.6'S, 25°15.1'E, 480 m, coll. R.S. Africana South Coast Hare Biomass Survey, 31 May 1990; 1 ♂ (23.7 × 18.5 mm), 1 ovigerous ♀ (36.0 × 28.5 mm), 1 ♀ (24.5 × 18.4 mm) ( SAM-A47872), stn NAN401 T027, 34°20.2'S, 18°12.7'E, 290 m, coll. L Atkinson, Nansen West Coast Survey, 15 January 2007; 1 ♂ (40.7 × 31.1 mm) ( AM P34653), off Cape Town, 34°21'S, 17°57'E, coll. 18 December 1929; 3 ♂♂ (34.6 × 27.3 mm, 29.3 × 23.1 mm, 22.0 × 17.0 mm) (NHM 1924.7.19.1-3), stn 103, Cape, no other data. SOUTH ATLANTIC • 1 ♀ (21.5 × 18.9 mm) ( ZMB 26204), stn 153/1968, 28°22'S, 14°24'E, 470-460 m, coll. E Haeckel, 9 May 1968.

Diagnosis.

Carapace pyriform, covered with short setae. Pseudorostral spine short, diverging. Supraorbital eave with sharp preorbital spine; postorbital lobe fused to hepatic plate on large size specimens. Carapace with plates: 1 hepatic plate pointing upwards, 1 short mesogastric spine above 1 oblong mesogastric plate, 1 large protogastric granule, 1 oblong cardiac plate, 1 large epibranchial plate, 1 mesobranchial plate, 1 posterior blunt spine, 1 lateral branchial plate curved upwards (Fig. 10A ). Plates less distinct on juvenile specimens. Antennal flagellum equal to or slightly longer than pseudorostral spines. Basal antennal article with convex outer margin, with blunt distal angle of article. Buccal frame covered by third maxilliped, distal angle of buccal frame raised, distinct. Pterygostomial region plate-like with 3 or 4 granules on outer margin (Fig. 10B ). Chelipeds slender, propodus longer than fingers, slightly carinate; carpus with granules on carina margin; merus triangular in cross-section, granulated on edge. Ambulatory legs slender; merus cylindrical; male P2 merus length 0.8-1.2 times carapace length, female P2 merus length 0.4-0.8 times carapace length, male P2 merus length 10.9-14.9 times width, female P2 merus length about 8.5 times width; male P5 merus length 0.4-0.6 times carapace length, female P5 merus length 0.4-0.5 times carapace length, male P5 merus length 4-6.8 times width, female P5 merus length 4.6-5.8 times width (Figs 10A , 14C, D ). Male thoracic sternum wide, concave on sternites 1-4; regions well defined; sternites 3, 4 widest, lateral margins slightly constricted medially. Male pleon with triangular telson; surface of somites smooth (Fig. 10B ). G1 straight with flattened sharp tip (Fig. 15A-D ).

Remarks.

The author and year of publication for Scyramathia hertwigi has traditionally been cited as Doflein (1904). Doflein (1904: 81), however, cited a figure of this species in Chun (1900). Hence, the authorship and date of publication for S. hertwigi should be "Doflein in Chun 1900 " (see Low et al. 2017). The figure by Doflein that is in Chun (1900) was stated to be drawn to scale ( Low et al. 2017). Doflein (1904), when describing the species, did not specify the number of specimens examined, but mentioned that many male and female specimens were examined. The specimen that was figured by Doflein, in Chun (1900), is currently deposited in ZMB. The measurement of the male specimen deposited in the Museum für Naturkunde, Berlin ( ZMB) is very similar to that drawn by Doflein, in Chun (1900) and we are confident they are the same specimen. The location where this specimen was collected matches that listed in Doflein (1904). Since no type was designated in Chun (1900) or Doflein (1904), this male specimen ( ZMB 13699) is herein designated as the lectotype of S. hertwigi .

The Atlas by Doflein (1904: pl. 27 figs 1-7) has figures that show a series of sizes of the carapace with plates, in particular the horse-shoe shaped epibranchial plate. In this species, the pseudorostral spines are always proportionately shorter than those in S. carpenteri . The differences between S. carpenteri and S. hertwigi were discussed by MacPherson (1983: 35), and we agree with his interpretation. There are also slight variations amongst the specimens from South Atlantic ( SMF 23085), which tend to have less distinct plates on the carapace, and slightly shorter and stouter ambulatory legs while a large specimen ( AM P34653) from South Africa has distinct plates on carapace, and somewhat longer and slender ambulatory legs. These differences, however, are not substantial and should not be a reason to treat them as different.

The specimens of " Scyramathia carpenteri " from off Cape Bajador, West Africa (= off Boujdour, Western Sahara) reported by Tavares and Santana (2018: 204) may not be that species. This location overlaps with the distribution range of S. tenuipes sp. nov., and it is possible their specimens belong to this species instead. Their material will need to be re-examined.

Distribution.

Scyramathia hertwigi is known from its type locality, off Cape Point and on Agulhas Bank, South Africa, as well as parts of the south Atlantic along the African coast. It is the only species that enters the southwestern-most edge of the Indian Ocean.

Figures

Figure 10. Scyramathia hertwigi Doflein, in Chun 1900, lectotype male (33.7 x 27.0 mm) (ZMB 13699), South Atlantic Ocean. A. overall dorsal view; B. overall ventral view; C. lateral view of carapace.

Figure 14. Dorsal view of P 5. A, B. Scyramathia carpenteri (Norman, in Thomson 1873); A. male (41.3 x 34.0 mm) (NHM 1983.449), North Sea; B. ovigerous female (35.8 x 29.0 mm) (NHM 1978.99), Atlantic Ocean; C, D. S. hertwigi Doflein, in Chun 1900; C. male (34.6 x 27.3 mm) (NHM 1924.7.19.1 - 3), South Africa; D. female (24.5 x 18.4 mm) (SAM-A 47872), South Africa; E, S. umbonata (Stimpson, 1871), female (36.7 x 27.9 mm) (NSMT-Cr 7178), off Suriname; F-J. S. tenuipes sp. nov.; F. holotype male (33.9 x 26.3 mm) (ICMD 288), Mediterranean Sea; G. paratype male (29.7 x 22.0 mm) (ICMD 000707), Mediterranean Sea; H. paratype male (32.0 x 25.4 mm) (ZRC 2019.1636), Mediterranean Sea,; I. paratype ovigerous female (31.2 x 24.6 mm) (ICMD 000708), Mediterranean Sea,; J. paratype ovigerous female (32.2 x 25.8 mm) (ZRC 2019.1635), Mediterranean Sea.

Figure 15. A-D. Scyramathia hertwigi Doflein, in Chun 1900, paralectotype male (24.7 x 19.0 mm) (ZMB 13700), Agulhasstrom [= Agulhas current], left G 1; E-H. Scyramathia tenuipes sp. nov., holotype male (33.9 x 26.3 mm) (ICMD 288), Mediterranean Sea, left G 1. A, E. ventral view; B, F. ventral view of distal portion; C, G. dorsal view; D, H. dorsal view of distal portion. Scale bars: 1 mm.