Glypturus acanthochirus Stimpson, 1866

Felder, Darryl L., 2019, Designation of a neotype for Glypturus rabalaisae Sakai, 2011, a ghost shrimp from continental shelf waters of the northern Gulf of Mexico (Crustacea: Decapoda: Callianassidae), Zootaxa 4679 (1), pp. 194-200 : 197-198

Glypturus acanthochirus Stimpson, 1866

Glypturus acanthochirus Stimpson, 1866: 46 .

Glypturus acanthochirus Stimpson. — Stimpson 1871: 121; Kingsley 1899: 821; Rathbun 1900: 150; 1901: 93; Borradaile 1903: 548; De Man 1928: 19, 25, 180; Manning 1987: 390, fig. 3 a–h (not fig. 4 a–d); Poore & Suchanek 1988 p. 201, fig. 4 d; Manning & Felder 1991: 778, fig. 2 “ Glypturus ”; Dworschak 1992: 209; Dworschak & Ott 1993: 282; Collins et al. 1996: 54, pl. 12, fig. 1; pl. 15, figs. 1, 3, 4; Sakai 1999: 73 (part), fig. 14 i; Tudge et al. 2000:144; Curran & Martin 2003: 230, 234, fig. 4 B; Dworschak 2004: 20, fig. 4 F; Sakai 2005: 133; Ngoc-Ho 2005: 73; Abed-Navandi & Dworschak 2005: 160; Collins et al. 2009: 70; Felder & Robles 2009: 338, fig. 1, table 1; Felder et al. 2009: 1062, 1093; Sakai 2011: fig. 65 A, B; Dworschak et al. 2012: 169, 171, 177, 192, fig. 69.31Q; Hyžný & Müller 2012: 970–975, 981, 984, 985, 987, fig. 1 A, B; fig. 2 A–C; fig. 3 A–C, I; fig. 4 C; Komai et al. 2015: 14–18, 28, 29, 51–54, table 1.

Callianassa (Callichirus) acanthochirus (Stimpson) .— Schmitt 1935: 4, 20, pl. 1 fig. 6, pl. 2 fig. 5, pl. 3, fig. 4, pl. 4 fig. 6; (not Heard & Reames 1979: 52 = G. rabalaisae ).

Callianassa acanthochirus (Stimpson) .— Gurney 1944: 84; Biffar 1971: 637, 639-642, 655-661, figs. 3 a–i, 4 a–f; (not Heard & Reames 1979: 52, fig. 1, = G. rabalaisae ).

Callichirus acanthochirus (Stimpson) .—de Saint Laurent & Le Loeuff 1979: 96.

Material examined.Southeastern Gulf of Mexico (Florida Keys): 1 male (photograph voucher) pocl 15.9 mm ( ULLZ 14962 ), Sugarloaf Key , 24° 37’ 28.474”N, 81° 32’ 35.469”W, 0.5 m, shallow grassbed, 16 May 2013 ; 1 male, pocl 14.2 mm ( USNM 122438), Dry Tortugas, 5 August 1930 . Cuba (Isla de la Juventud): 1 female (photograph voucher), pocl 30.3 mm ( ULLZ 14885 ), Punta del Este , grassbed, 12 June 1995 ; 1 female, pocl 23.6 mm ( ULLZ 14884 ), Playa Punta Francés , 10 June 1995 . Belize: 1 ovigerous female, pocl 9.7 mm ( ULLZ 11112 ), Twin Cays , grassbed near mangrove shoreline, 20 February 2009 . Puerto Rico: 1 male, pocl 13.0 mm ( USNM 266220 ) Parguera Bay , Lajas, 6 January 1955 . Turks and Caicos Islands: 1 female, pocl 13.5 mm ( USNM 205996 ), Pine Cay , 9 April 1988 . Jamaica: 1 male (genetic voucher), pocl 12.9 mm ( USNM 1541512 = ULLZ 6528 ), Montego Bay , shallow rubble-strewn sandy grassbed, 16 May 2003 . Venezuela: 1 female, pocl 28.2 mm ( USNM 286415 ), Gulf of Cariaco , 10° 33’ 05.3’’N, 63° 49’ 20.3’’W, 0.7 m, 18 February 1977 . Dutch Antilles ( Aruba): 1 female, pocl 8.5 mm ( USNM 221787 ), Klein Lagoon , 6 January 1987 .

Diagnosis.Carapace with well-defined dorsal oval, front with three spines, median spine forming rostrum reaching to or beyond middle of cornea. Eyestalk cornea darkly pigmented, inflated, disk-shaped, subterminal, not covering full width of eyestalk, not encompassing distal stalk margin. Antennal (second antenna) peduncle reaching beyond antennular (first antenna) peduncle in mature specimens, distal end of antennular peduncle reaching to, not beyond, distal end of penultimate article of extended antennal peduncle. Major cheliped palm with 1–4 spines along dorsal margin, carpus with typically 5–8 spines along ventral margin. Minor cheliped carpus length (measured midheight of outer surface) slightly less than to slightly greater than median length of palm (measured mid-height of outer surface, extending to gape). Telson posterior margin lacking median spine or tooth. Pigmentation in life shades of orange and golden brown over lighter yellowish background, usually with rusty diffuse patches on chelae, other appendages, and body. Applicable GenBank sequence accession numbers for USNM 1541512 = ULLZ 6528 from Jamaica: (16s) EU882929 , (12s) EU875039 .

Size.Carapace length of mature in both sexes typically of pocl 10–20 mm, less commonly ranging to a known maximum of 35 mm; however, successful extraction of large specimens is difficult and the abundance of large diameter burrows suggests such large individuals may occur frequently in subtidal seagrass beds.

Habitat.Infaunal burrower in intertidal and nearshore subtidal sediments of calcareous protected beaches and mud flats, including emergent to subtidal seagrass beds and deeper bottoms of small embayments with vegetated margins; 0– 13 m.

Distribution.Western Atlantic: Bahamas; Florida southeastern Atlantic coast and Keys; Gulf of Mexico (sw, se); Cuba; Belize; Puerto Rico; Jamaica; Curaçao; Lesser Antilles; Caribbean mainland margins and coastal islands of Central and northern South America to Colombia and Venezuela.

Remarks.As already established, the specimens reported as Callianassa acanthochirus and illustrated by Heard & Reames (1979) and Rabalais et al. (1981) do not depict Glypturus acanthochirus but instead Glypturus rabalaisae . However, morphological features of G. acanthochirus are illustrated in a number of widely available references ( Schmitt 1935: pl. 1 fig. 6, pl. 2, fig. 5, pl. 3, fig. 4, pl. 4 fig. 6; Biffar 1971: figs. 3 a–i, 4 a–f;; Manning 1987: fig. 3 a–h; Manning & Felder 1991: fig. 2 “ Glypturus ”; Collins et al. 1996: pl. 12, fig. 1; pl. 15, figs. 1, 3, 4; Sakai 1999: fig. 14 i; Curran & Martin 2003: fig. 4 B; Dworschak 2004: fig. 4 F; Sakai 2011: fig. 65 A, B; Dworschak et al. 2012: fig. 69.31Q; Hyžný & Müller 2012: fig. 1 A, B; fig. 2 A–C; fig. 3; A–C, I; fig. 4 C).

In both G. rabalaisae and its regional congener, G. acanthochirus , the major cheliped palm bears 1–3 spines along its dorsal margin, while the carpus usually has 5–8 spines along its ventral margin. In both species, the eye corneas are disk-shaped and narrower than the eyestalk, positioned distinctly short of the eyestalk distal margin. However, the two species otherwise differ markedly, both morphologically and ecologically, as well as genetically ( Felder & Robles 2009). While G. rabalaisae is apparently restricted to muddy fine siliceous sandy to sandy mud offshore bottoms of the inshore to mid-continental shelf (6.5–91 m depths, per Rabalais et al. 1981), G. acanthochirus is typically found in intertidal to subtidal inshore grassbeds and sand flats (0–13 m depths), usually in areas of predominently calcareous sediments ( Dworschak et al. 2012). G. acanthochirus also reaches much larger sizes than does G. rabalaisae , and coloration in life differs markedly between the two species. The shades of rose pink coloration on the chelae, other appendages, and the body in typical adults of G. rabalaisae are usually in striking contrast to patterning in shades of orange, golden brown, and diffuse rust on chelae, other appendages, and the body seen in most specimens of G. acanthochirus , these colors sometimes being intensely developed on upper surfaces, as well as near appendage articulations and tips.

As noted by Sakai (2005; 2011), morphological distinction of the two species can usually be based on the telson alone, which bears a small median spine or triangular tooth on the posterior margin in G. rabalaisae , this being absent in G. acanthochirus . It should be noted, however, that this small spine or tooth can be easily overlooked when translucent in small specimens, and it may also be easily compressed or broken in the process of collection. Additionally, in G. rabalaisae , the median length of the minor cheliped carpus is distinctly greater than the median length of the palm. In G. acanthochirus , the median length of the minor cheliped carpus is instead usually only slightly greater than, subequal to, or slightly less than the median length of the palm, the variation dependent upon sex and maturity of the specimen. Also, the major chela in mature specimens of G. rabalaisae , in those cases where it is intact, appears to be more ovoid than in G. acanthochirus . It appears to be relatively broad proximally with the upper and lower margins arched to converge distally, apparently moreso than in available specimens of G. acanthochirus . However, confirming the diagnostic value of this feature will require additional mature specimens of G. rabalaisae with intact mature chelipeds.

While Sakai (2005) appears to have confused relative lengths of antennular and antennal peduncles, Sakai (2011) gave a corrected comparative account that can also be applied to separation of G. rabalaisae from G. acanthochirus , with some modification and caution. In specimens of G. rabalaisae , the distal end of the antennular peduncle reaches slightly but distinctly beyond the distal end of the fully extended antennal penultimate article, while in mature specimens of G. acanthochirus it reaches almost exactly to the distal end of that article. Study of specimens across a wide range of sizes has shown this character to dependably separate specimens of G. rabalaisae from all except juvenile specimens of G. acanthochirus , so long as the antennal peduncle is manipulated to full extension.