Scyramathia carpenteri (Norman, in Thomson, 1873)
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publication ID |
https://dx.doi.org/10.3897/zse.96.48041 |
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publication LSID |
lsid:zoobank.org:pub:E1A270E2-98E0-4F34-9BFB-DCC49CCFAE47 |
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persistent identifier |
https://treatment.plazi.org/id/89D4A77E-FCA0-5B3F-A2B9-FBA3D6952549 |
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treatment provided by |
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scientific name |
Scyramathia carpenteri (Norman, in Thomson, 1873) |
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Scyramathia carpenteri (Norman, in Thomson, 1873) Figs 3 View Figure 3 , 4A-C View Figure 4 , 5A-C View Figure 5 , 6A-F View Figure 6 , 7A-D View Figure 7 , 8A-H View Figure 8 , 9A-I View Figure 9 , 14A, B View Figure 14
Amathia carpenteri Norman, in Thomson 1873: 175 (fig.), 176, fig. 35 (type locality: "sandy chalk of the Holtenia ground" [= between North Scotland and the Faeroe Islands]).
Scyramathia Carpenteri : A. Milne-Edwards 1880a: 356 [new combination]; A. Milne-Edwards 1880b: 277; Filhol 1885: 123, 154, fig. 38; Sars 1885: 6-11, 274, pl. 1 figs 1-7; Perrier 1886: 208, fig. 217; Smith 1886: 625[21], 626[22]; Bourne 1890: 308; A. Milne-Edwards and Bouvier 1894: 13, 14 (in part); A. Milne-Edwards and Bouvier 1899: 43 (in part); Doflein 1904: 81 (list); A. Milne-Edwards and Bouvier 1900: 133-138, pl. 20 fig. 1-10; Hansen 1908: 12; Bouvier 1922: 81 (in part); Grieg 1927: 44-45.
Anamathia Carpenteri : Smith 1886: 626[22]; Pocock 1889: 425, 426; Bourne 1890: 314, 315.
Anamathia carpenteri : Faxon 1895: 10.
Rochinia carpenteri : Rathbun 1925: 204 (list) [new combination]; Miranda y Rivera 1933: 41; Sivertsen and Holthuis 1956: 49; Allen 1967: 35 (list), 64 (key), 97 (fig.); Sankarankutty 1968: 51, figs 5D-F; Christiansen 1969: 20, 122-124, 123 (map), fig. 50; Ingle 1979: 47-53, 59, figs 1-7; Ingle 1980: 15 (list), 19 (table), 20 (table), 140, fig. 108, pl. 33 fig. b; Manning and Holthuis 1981: 254; Shelton and Dooley 1982: 109; Clark 1986: 190, 191 (map); Griffin and Tranter 1986: 180 (list); Rice 1990: 10, fig. 7; Tavares 1991: 161 (list), 172; d’Udekem d’Acoz 1999: 194 (in part); Casadío et al. 2005: 158 (list); Ng and Richer de Forges 2007: 63 (list); Ng et al. 2008: 105 (list); Ng and Richer de Forges 2013: 362, fig. 5B.
Rochinia Carpenteri : Bouvier 1940: 344, 345 (in part).
Scyramathia carpenteri : Tavares and Santana 2018: 204 (in part).
Material examined.
Lectotype: ♂ (21.6 × 15.9 mm) (NHM 1907.8.28.3), stn 47, 'Holtenia ground’, 59°34'N, 7°18'W, 958 m, coll. H.M.S. “Porcupine”, 1869. Paralectotypes: 1 ♀ (13.0 × 8.4 mm) (NHM 1911.11.8.377), same locality and collection data as lectotype; 1 damaged juvenile ♀ (5.4 × 3.0 mm) (NHM 1910.2.4.213), stn 48, 'Holtenia ground’ 59°32'N, 6°59'W, coll. H.M.S. “Porcupine”, 1869. Other material: Scotland/North Sea • 1 ♂ (35.0 × 27.1 mm) (NHM 1981.108), stn 18, Sula Sgeir, 59°33.7'N, 06°49'W to 59°29.5'N, 06°43.3'W, 915-880 m, coll. A Wheeler, 16 July 1973; 2 ♂♂ (41.3 × 34.0 mm, 38.8 × 31.6 mm) (NHM 1983.449), 56°23'N, 09°18.2'W, 1010-1030 m, coll. W Wales, 20 October 1977; 7 ♂♂ (37.1 × 30.5 mm, 35.0 × 27.6 mm, 30.5 × 23.0 mm, 28.2 × 22.7 mm, 24.6 × 17.2 mm), 3 ♀♀ (37.1 × 30.6 mm, 33.5 × 27.5 mm, 22.4 × 17.2 mm), 1 ovigerous ♀ (35.8 × 29.0 mm) (NHM 1978.99), Atlantic Ocean, 56°33'N, 09°13'W to 56°30'N, 09°14'W, 750 m, coll. RW Ingle, 23 October 1977. Porcupine Seabight • 3 ♂♂ (25.0 × 18.9 mm, 15.5 × 11.1 mm, 9.0 × 6.2 mm), 1 ♀ (34.8 × 28.2 mm), 1 ♀ (with bopyrid; 15.6 × 11.6 mm) (National Oceanography Centre), stn 50601, 51°19.2'N, 11°41.1'W - 51°21.1'N, 11°42.9'W, 927-770 m, coll. H.M.S. “Discovery” Collection, 1 July 1979; 1 ♂ (23.9 × 18.4 mm), 3 ♀♀ (17.1 × 13.8 mm, 13.6 × 10.6 mm, 12.5 × 9.4 mm) (National Oceanography Centre), stn 9752 #1, 51°16.3'N, 11°42.5'W - 51°18.6'N, 11°42.8'W, 1010-1045 m, coll. H.M.S. “Discovery” Collection, 7 April 1978.
Diagnosis.
Carapace pyriform, strong diverging pseudorostral spines. Postorbital and hepatic spine fused, forming distinct L-shape plate on larger specimens. Carapace with 1 oblong mesogastric plate, 1 oblong cardiac plate, 2 metabranchial plates, 2 horseshoe-shaped epibranchial plates (Figs 3 View Figure 3 , 4A View Figure 4 , 5A View Figure 5 , 7A, C View Figure 7 , 9A-I View Figure 9 ). Lateral branchial spine plate-like on specimens with strong carapace plates, present as strong spine on specimens with weak carapace plates (Figs 3 View Figure 3 , 4A View Figure 4 , 5A View Figure 5 , 7A, C View Figure 7 , 9A-I View Figure 9 ). Male thoracic sternum deeply concave with distinct grooves (Figs 4B View Figure 4 , 5B View Figure 5 , 6D View Figure 6 ). G1 straight, with flattened, sharp tip; straight top margin (Fig. 8C-F View Figure 8 ).
Description.
Carapace covered by a thick tomentum of setae; with several plates and spines. Pseudorostral spines sharp, straight, diverging, slightly deflected. Supraorbital eave with sharp preorbital spine; sharp angle preorbital spine on juvenile specimens. Hepatic spine pointing upwards, fused with postorbital plate; proportionally longer on juvenile specimens (Figs 4C View Figure 4 , 5C View Figure 5 , 6A, B View Figure 6 , 8A, B View Figure 8 ). Carapace with plate-like structures: 1 oblong mesogastric plate; 1 oblong cardiac plate; 2 metabranchial plates; 2 horseshoe-shaped epibranchial plates (Figs 3 View Figure 3 , 4A View Figure 4 , 5A View Figure 5 , 7A, C View Figure 7 , 9A-I View Figure 9 ). One long sharp branchial spine pointing laterally; proportionately longer in juveniles and specimens with weak carapace. One large intestinal granule on posterior border of carapace (Figs 3 View Figure 3 , 4A View Figure 4 , 5A View Figure 5 , 7A, C View Figure 7 , 9A-I View Figure 9 ).
Antennal flagellum shorter than pseudorostral spines, about half or nearly equal in length. Basal antennal article fused to carapace; longer than broad; straight to gently convex outer margin; blunt distal angle of article. Pterygostomial region with several granules on outer margin (Figs 4B View Figure 4 , 5B View Figure 5 , 6C View Figure 6 , 7B, D View Figure 7 ). Buccal frame square, covered by third maxiliped; strong, blunt distal angle of buccal frame (Figs 4B View Figure 4 , 5B View Figure 5 , 6C View Figure 6 , 7B, D View Figure 7 ).
Chelipeds long, slender; propodus longer than dactylus; dactylus curved, serrulated along entire length (Fig. 6E View Figure 6 ); carpus short with granules on margin, dorsal margin carinated; merus with 1 tooth on distal upper border. Ambulatory legs slender; merus with sharp angle on distal end; male P2 merus length between 0.6-1.3 times carapace length, female P2 merus length between 0.8-1.0 times carapace length for female, male P2 merus length 8.2-14.0 times width, female P2 merus length 10.5-13.4 times width; male P5 merus length 0.4-0.6 times carapace length, female P5 merus length 0.3-0.5 times carapace length, male P5 merus length 4.2-7.3 times width, female P5 merus length 4.6-5.8 times width (Figs 3 View Figure 3 , 4A View Figure 4 , 5A View Figure 5 , 14A, B View Figure 14 ).
Male thoracic sternum with sternites 1-4 deep concave; sternites 1, 2 wider than long; sternites 3, 4 widest at base, lateral margin slightly constricted; sternites strongly defined (Figs 4B View Figure 4 , 5B View Figure 5 , 6D, F View Figure 6 ,). Male pleon with triangular telson and 6 somites, all free; widest on second and third somites. Adult female with round pleon, with all somites distinct. G1 straight, with flattened, sharp distal tip; straight top margin; slightly constricted at distal region (Fig. 8C-F View Figure 8 ).
Remarks.
The identity of Amathia carpenteri Norman, in Thomson 1873 s. str., is critical to the status of Scyramathia as it is the type species of the genus. Although Tavares and Santana (2018) clarified the identity of the genus and had material of the species, they did not examine the types for this species. The species was named by Thomson in 1873 in his famous book about the exploration of the deep Atlantic by the H.M.S. Porcupine, "The Depths of the Seas" (p. 175: fig. 35; reproduced here as Fig. 3 View Figure 3 ), under the name " Amathia Carpenteri " to honour his colleague Dr. W.B. Carpenter. There was no clear indication of number of specimens examined, with the author only commenting that "Another handsome new species, Amathia carpenteri , Norman (fig. 35), was common in the sandy chalkmud of the Holtenia ground." ( Thomson 1873: 176). The figure shows that the cardiac region of the carapace appeared to be damaged ( Thomson 1873: fig. 35; reproduced here as Fig. 3 View Figure 3 ). In the NHM are three specimens that are labelled as syntypes of A. carpenteri , all obtained by the H.M.S. Porcupine. None of these specimens, however, match the measurements of the type figure, which was "once and a half the natural size" ( Thomson 1873: fig. 35; reproduced here as Fig. 3 View Figure 3 ). Of these, one male specimen (NHM 1907.8.28.3) agrees relatively well with the figure by Thomson (1873: fig. 35; Fig. 3 View Figure 3 ), and the specimen label mentions that it was figured in Thomson (1873). This specimen, with catalogue number, NHM 1907.8.28.3, was noted by Christiansen (1969: 122) to be the lectotype for this species, and in an unpublished note, was also selected by Isabella Gordon (also unpublished data) to be the lectotype. The same specimen was also mentioned by Rice (1990: 10), noting that it is similar to the figure by Norman, in Thomson (1873: fig. 35). The type locality of this species was stated to be on "sandy chalk of the Holtenia ground". Holtenia Ground is an area between North Scotland and the Faeroe Islands that covers an area of approximately 500 km2, with a depth of 820 to 1000 m ( Carpenter et al. 1870; Reiswig and Champagne 1995). Specimen NHM1907.8.28.3 is here formally designated as the lectotype of Amathia carpenteri Norman, in Thomson 1873, to stabilise the taxonomy of the species and the genus.
The three type specimens differ markedly from each other in many ways although they are all from Holtenia Ground. The lectotype male (21.6 × 15.9 mm, NHM 1907.8.28.3) selected here differs markedly from the other two paralectotypes in having a smoother carapace, without the distinct raised plate-like structures on the carapace and the branchial regions are also proportionately more inflated (Figs 4A View Figure 4 , 7A View Figure 7 ). The next largest type is a subadult female (13.0 × 8.4 mm, NHM 1911.11.8.377), and its carapace more closely resembles typical S. carpenteri , with the plates more developed. It is almost certainly the same specimen figured by Norman, in Thomson (1873: fig. 35; Fig. 3 View Figure 3 ), with the shape and structures of the spines and plates agreeing very well, althought the left pseudorostral spine of the specimen is now broken (Fig. 7C View Figure 7 ). The third type specimen is a small and poorly preserved juvenile female (5.4 × 3.0 mm, NHM 1910.2.4.213) in which the dorsal surface of the carapace as well as the third maxillipeds are covered with setae but without any obvious plates. The surfaces of the third maxillipeds of the other two type specimens are finely granulated or smooth (Figs 4B View Figure 4 , 7B, D View Figure 7 ).
Scyramathia carpenteri exhibits strong variation on the plate-like structures on the carapace of various sized specimens showed variation. D’Udekem d’Acoz (1999) observed that “L’ornementation de la carapace de R. carpenteri est extrêmement variable" but did not mention if it is due to the size of the specimens. Similar sized specimens showed either weak or strong plate-like structures (Fig. 9A-I View Figure 9 ). These differences are also seen in the type specimens where the larger sized male lectotype specimen has weak plate-like structures on the carapace whereas the same structures on the smaller sized female paralectotype specimens are relatively stronger. The variation of the plate-like structures on the carapace are therefore, not always size dependent. Other morphological characters that show variation on S. carpenteri includes the divergence of the pseudorostral spines, from relatively divergent as seen on the lectotype (Fig. 4A View Figure 4 ) to subparallel as seen on the male specimen, with catalogue number, NHM 1983.449 (Fig. 5A View Figure 5 ); the hepatic region having a hepatic spine or plate (Figs 4A View Figure 4 , 5A View Figure 5 , 7A, C View Figure 7 , 9A-I View Figure 9 ); and the lateral branchial spine on the carapace, from relatively straight, slightly curved or plate-like (Figs 4A View Figure 4 , 5A View Figure 5 , 7A, C View Figure 7 , 9A-I View Figure 9 ).
Superficially, S. carpenteri resembles S. umbonata (Stimpson, 1871) from the western Atlantic, which also appears to grow to a much larger size (57 mm maximum carapace length; see Tavares et al. 2015). There are, however, consistent differences, with S. carpenteri , which has relatively longer pseudorostral spines, and the outer margin of the basal antennal article is always straight or only slightly convex. The pseudorostral spines of S. umbonata are always proportionately shorter, even when similar sized specimens are compared, and the outer margin of the basal antennal article is always distinctly convex (cf. Tavares et al. 2015: figs 1, 2, 4, 5). These differences are reliable for specimens of similar sizes. As such both species are here recognised as separate taxa.
It is interesting to note that some studies (A. Milne-Edwards and Bouvier 1899, 1900; Bouvier 1922, 1940) mentioned that S. carpenteri does not occur in the Mediterranean, which is the region where the species, S. tenuipes sp. nov., is now found (see remarks for S. tenuipes sp. nov.). Alphonse Milne-Edwards and Bouvier (1899, 1900) and Bouvier (1940) had material they referred to " S. carpenteri " from the Azores, and up north of São Jorge, and the Sahara beach. Based on their figures (see A. Milne-Edwards and Bouvier 1899: pl. 1 fig. 4; A. Milne-Edwards and Bouvier 1900: pl. 20 Figs 1 View Figure 1 , 6 View Figure 6 ; Bouvier 1940: pl. 14 fig. 1), however, the specimens they figured are more similar to S. tenuipes sp. nov., with the ambulatory legs long and slender, and these records are hence referred there for now. The plates on the carapace as figured (see A. Milne-Edwards and Bouvier 1899: pl. 1 fig. 4; A. Milne-Edwards and Bouvier 1900: pl. 20 Figs 1 View Figure 1 , 6 View Figure 6 ; Bouvier 1940: pl. 14 fig. 1) appear relatively stronger than what has been observed in S. tenuipes sp. nov., but as discussed earlier, this character is known to vary in S. carpenteri s. str. in any case.
Distribution.
Scyramathia carpenteri is known from the type locality, "sandy chalk of the Holtenia ground" [= between North Scotland and the Faeroe Islands] ( Carpenter et al. 1870; Norman, in Thomson 1873; Reiswig and Champagne 1995), South Iceland ( Hansen 1908), Southwest Faeroe Islands, South of Norway, West of British Isles ( Clark 1986).
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