Glyptoxanthus erosus ( Stimpson, 1859 )

Mendoza, Jose Christopher E. & Guinot, Danièle, 2011, Revision of the genus Glyptoxanthus A. Milne-Edwards, 1879, and establishment of Glyptoxanthinae nov. subfam. (Crustacea: Decapoda: Brachyura: Xanthidae), Zootaxa 3015, pp. 29-51 : 38-40

Glyptoxanthus erosus ( Stimpson, 1859)

( Figs. 1 E, F, 5, 10E)

Actaea erosa Stimpson, 1859: 51 (type locality: Florida, U.S.A.).

Glyptoxanthus erosus, A. Milne-Edwards 1879: 254 , pl. 43 fig. 3, pl. 44 fig. 4. — Rathbun 1930: 263, pl. 107 figs. 1–4. — Williams 1965: 185, figs. 167, 183A; 1984: 398, figs. 312, 331b. — Guinot 1967: 556, fig. 30a, b; 1971: 1072; 1979: 66, figs. 18D, 23B, pl. 6 fig. 2. — Felder 1973: 60, pl. 9 fig. 9. — Abele & Kim 1986: 57, 655 fig. c. —Ng et al. 2008: 199 (list).

Material examined. U.S.A.: Neotype (presently designated), male, 47.3 × 32.9 mm ( USNM 25573), Biscayne Bay, Florida, coll. G.E. Benedict, 1901.

Other material. 1 male, 25.5 × 17.9 mm (MNHN-B8354), Florida, don. Smithsonian Institution, Jul. 1899; 1 male, 47.7 × 34.5 mm ( USNM 76271), Bird Key reef, Tortugas Is., Florida, coll. Manter, 28 Jun. 1931, don. W.L. Schmitt, det. M.J. Rathbun; 1 male, 44.3 × 32.8 mm ( USNM 119500), from rocky ledge, 97 ft, 5 miles off Destine, Florida, coll. 17 Feb. 1962, det. R.B. Manning; 1 ovig. female, 67.0 × 47.0 mm ( USNM 168866), Calico scallop grounds, south of Beaufort Islet, North Carolina, coll. H.J. Porter/ Ensign, 5 Sep. 1972, det. A.B. Williams; 1 male, 77.2 × 55.0 mm ( USNM 237609), stn 13, otter trawl, 156 fms, USA east coast, coll. R. Lemaitre/RV Bellows; 1 male, 53.1 × 38.1 mm ( ZRC 1998.9, ex. USNM 168865), 60–65 feet, Sapelo Island, 4.75 miles off Whistle Buoy, Georgia, coll. M. Gray, 7 Apr. 1966, det. A.B. Williams, 1977.

Jamaica: 1 male, 20.9 × 14.4 mm (RMNH-D27715), stn 1230, 17º51.6’N, 77º57.8’W, coll. Pillsbury, 7 Jul. 1970, det. L.B. Holthuis.

Mexico: 1 male, 16.3 × 11.4 mm, 2 females, 14.0 × 10.4 mm, 24.5 × 17.5 mm, 1 juv., 5.8 × 4.7 mm ( USNM 9585), stn. 2365, 44 m (24 fms), 22º18'00"N 87º04'00" W, north of Yucatan Peninsula, Gulf of Mexico, coll. Albatross, 30 Jan. 1885; 2 males, 12.7 × 8.9 mm, 26.9 × 19.1 mm, 1 female, 22.8 × 16.5 mm ( USNM 15001), off Yucatan Peninsula, stn 2363, coll. Albatross, 1885.

Diagnosis. Carapace transversely ovate, width-to-length ratio about 1.4; regions more-or-less defined, with several small, discrete, subcircular cavities included within; cervical groove deep; 1M fused to 2M; 2M poorly divided or entire, fused to 3M posteriorly; 4M bridging 3M and 1P; 2L, 3L, 4L distinct; 5L and 6L fused; 2P Xshaped; vermiculations regular, symmetric, rather convoluted, retaining traces of fused granules; small lobules immediately posterior to 1P slender and irregular in shape. Front quadrilobate. Anterolateral margin arcuate; divided into 4 low lobes; first lobe smallest, but prominent; fourth lobe subtriangular. Mxp3 deeply eroded. Male thoracic sternum also severely eroded, with cavities of various sizes arranged between granulate ridges in a moreor-less symmetric fashion. External surfaces of pereopods with similar vermiculate sculpturing as carapace. Abdomen with several transverse ridges on external surface, some of which are bridged together by one or shorter, longitudinal ridges. G1 long and slender, dorso-lateral wall of apex forming a narrow hood over aperture; with 1 or 2 short, simple setae on ventral margin of aperture; studded with spiniform granules subdistally; G2 about one-fourth length of G1.

Remarks. Stimpson (1859) described Actaea erosa from Florida, U.S.A. Alphonse Milne-Edwards (1879) subsequently transferred this species to Glyptoxanthus , along with other species previously in Actaea and Xantho , but did not formally designate a type species. Rathbun (1930) designated G. erosus as type species of Glyptoxanthus , and also reported that Stimpson’s type was no longer extant, but did not select a neotype. A large male specimen (47.3 × 33.0 mm, USNM 25573), from Biscayne Bay, Florida, and figured by Rathbun (1930: pl. 107), is designated here as the neotype of G. e ro s u s, in accordance with Article 75 of the Code. This action is deemed necessary for the stability of the genus and species, as G. e ro s u s is the type species of the genus, and as there are similar and/or sympatric species, such as G. vermiculatus and G. angolensis , with which it can be confused.

Glyptoxanthus erosus is easily distinguished from G. vermiculatus with which it shares part of its distributional range, by the presence of several, small, disjunct, subcircular cavities on the cardiac region (1P) (two transverse, parallel furrows on 1P in G. vermiculatus ). Except for their separate distributional ranges, G. e ro s u s could be easily confused with G. angolensis due to the strong similarities in their carapace sculpturing; although G. erosus tends to have more regular and symmetric vermiculations than G. angolensis , and also does not have the “doughnut”-like vermiculations observed in G. angolensis (see Remarks for G. angolensis ). The morphology of the G1 of these three related species varies considerably from each other ( Fig. 10 ). Rathbun (1930: 265) noted the colouration of a formalin-preserved specimen as “cream white with blotches and small spots of bright red, color especially persistent on walking legs, with dactyls red at base and yellowish distally.”

Ecology and geographical distribution. Glyptoxanthus erosus has been reported from the Atlantic coast of the United States (North Carolina to Florida), from the Gulf of Mexico, the Bahamas, the Yucatan Peninsula, and from the Caribbean Sea (see Rathbun 1930; Guinot 1979; Williams 1984). G. erosus has generally been collected subtidally from sandy to rocky and coralline bottoms to a maximum depth of 90 m (see Williams 1984).

Figures

FIGURE 1. Comparison of male thoracic sternums among representative xanthids: A, B, Actaeinae, Actaea semblatae Guinot, 1976 (22.5 × 17.4 mm, ZRC 2011.0700); B, C, Euxanthinae, Euxanthus huonii (Hombron & Jacquinot, 1846) (40.3 × 28.2 mm, ZRC 1987.471); E, F, Glyptoxanthinae subfam. nov., Glyptoxanthus erosus (Stimpson, 1859) (53.1 × 38.1 mm, ZRC 1998.9); and, G, H, Zalasiinae, Banareia nobilii (Odhner, 1925) (38.4 × 26.8 mm, ZRC 2011.0701). Black arrows denote position of sternal press-button.

FIGURE 10. Glyptoxanthus spp. gonopods (G 1). A, G. angolensis (Brito Capello, 1866); B, G. cavernosus (A. Milne-Edwards, 1878); C, G. erosus (Stimpson, 1859); E, G. c o r ro s u s (H. Mile Edwards, 1834); E, G. labyrinthicus (Stimpson, 1860), (LACM CR 1935.075.3); F, G. meandricus (Lockington, 1877), neotype (LACM CR 1940.65); G, G. vermiculatus (Lamarck, 1818). (A – C, D, G, after Guinot 1979).