Zuzalpheus longicarpus ( Herrick, 1891 ) Ríos, Rubén & Duffy, J. Emmett, 2007

Ríos, Rubén & Duffy, J. Emmett, 2007, A review of the sponge‑dwelling snapping shrimp from Carrie Bow Cay, Belize, with description of Zuzalpheus, new genus, and six new species (Crustacea: Decapoda: Alpheidae), Zootaxa 1602 (1), pp. 1-89 : 47-50

Zuzalpheus longicarpus ( Herrick, 1891) n. comb.

( Fig. 23 )

Alpheus saulcyi variety longicarpus ( Herrick, 1891) in part; Coutière 1897b:369.

Synalpheus laevimanus variety longicarpus: Coutière 1898a:189, 1898b:221 ; 1899; 1900:357.

Synalpheus longicarpus: Coutière, 1907:610, 1909: 53 , fig. 31; Christoffersen 1979: 344 in part; Williams 1984: 104 in part; Dardeau 1984: 64 in part; Ríos 2003:117, figures 2–22.

Material examined. (1) 1 ♂, 5.9 mm ( VIMS 93 CBC5506) , 1 ♀, 5.1 mm ( VIMS 93 CBC5515), South Water Cay , Belize, 28 March 1993, in Spheciospongia vesparium , 1.5 m .

(2) 5 ♂, 5.5, 6.7, 7.5, 7.5, 7.5 mm, 2 ♀, 7.9 and 8.1 mm, 2 ovigerous ♀, 6.7 and 7.5 mm ( VIMS 91 NC0101), off Morehead City , North Carolina, 3 July 1991, in yellow sponge otherwise resembling Spheciospongia vesparium .

(3) 5 ♂, 5.1, 7.0, 7.3, 7.5, 7.6 mm, 1 ♀, 8.4 mm ( USNM 1019063 , VIMS 93P3001), Guigalatupo reef, San Blas Islands, Panama, 28 September 1993, in Spheciospongia vesparium , 1 m .

Diagnosis. Body subcylindrical; carapace smooth, glabrous, with pterygostomian corner produced into bluntly acute angle, and posterior margin with cardiac notch diminished. Rostrum lanceolate, distally upturned, clearly narrower and slightly longer than ocular hoods. Orbitorostral process absent. Ocular hoods dorsally convex; in dorsal view, acute, margins straight, separated from rostrum by deep adrostral sinus. Ocular processes present, but not elongated. Ocellary beak in lateral view rod-like. Stylocerite slender; mesial margin straight, or convex; tip acute; reaching about as far as distal margin of first antennular peduncle; this latter segment without ventromesial tooth, and with 2 basal ventral processes. Basicerite without spine on dorsolateral corner, and with longer ventrolateral spine overreaching tip of stylocerite. Scaphocerite blade reduced, acute lateral spine robust, with lateral margin straight, reaching about as far as antennular peduncle; mesial projection at base of scaphocerite present. Maxilliped 3 with distal circlet of spines on distal segment and without ventrodistal spine on antepenultimate segment

Major pereopod 1 massive, fingers shorter than half length of palm; fixed finger reduced, considerably shorter than dactyl; in ventral view, outer face of fixed finger without any protuberance. Palm of chela somewhat inflated proximally, with distal superior margin produced into prominent tubercle with acute spine directed forward. Merus, extensor margin straight or slightly convex, with distal angular projection.

Minor pereopod 1 with palm more than twice as long as high; fingers clearly shorter than palm; dactyl with flexor margin straight, blade-like, with 2 strong distal teeth, subequal in length, and parallel to dactyl axis; transverse dorsal setal combs on extensor surface of dactyl very conspicuous; fixed finger with flexor margin straight, blade-like, with 2 strong teeth, subdistal one slightly smaller than distal one. Extensor margin of merus convex, ending in acute angle.

Pereopod 2 with carpus 5-segmented, not longer than merus.

Pereopod 3 slender; dactyl biunguiculate, with extensor tooth clearly thicker at base than flexor; merus without movable spines on flexor margin; mesial lamella on coxa present.

Pleura 1 of male with posterior corner hook-like, acutely produced ventrally and anteriorly; second through fifth pleurae of male strongly acuminate. Pleopod 1 of male, with about six terminal setae on endopod; second pleopod of male with marginal setae on exopod originating close to base; appendix interna on second to fifth male pleopods, present. Telson, space between distal spines equal or less than one-third of distal margin; marginal convex lobe present; posterior corners adjacent to spines rectangular. Anal flaps, perianal setae, and postanal setal brush absent. Uropods with 3 to 6 fixed teeth on outer margin of exopod, slightly apart from the longer mobile spine adjacent the internal fixed tooth.

Color. Translucent straw color with scattered chromatophores; distal portions of chelae purple to black; ovaries dull yellow, embryos dull brick-orange.

Variations. One of the most frequent variations is the widening of the orbital hoods (in dorsal view), which may be associated with the larger specimens. In those instances they resemble the hoof-shaped hoods in Zuzalpheus dardeaui , n. sp. The blade on the scaphocerite is usually reduced to less than half the length of the adjacent lateral spine, but occasionally exceeds this length. The spine overhanging the dactylar articulation on the major cheliped usually emerges at the most distal point of the protuberance, but occasionally arises from its ventral slope, as occurs in several other species. The number of fixed teeth on the outer corner of the uropodal exopod is most frequently from 4 to 6, but it can be anywhere from 3 up to 8. In a single specimen there was a postanal brush of stiff setae like the one in Zuzalpheus dardeaui , n. sp., but less dense.

Hosts and ecology. We have found Zuzalpheus longicarpus living only inside the canals of the loggerhead sponge Spheciospongia vesparium , as mentioned by several authors (e. g. Pearse 1950; Chace 1972; Dardeau 1984; Erdman and Blake 1987; Duffy 1992). Herrick (1891) reported that his type specimens came from Hircinia arcuta , currently known as Ircinia strobilina ( Lamarck 1816) , a large dark sponge superficially similar in appearance to Z. vesparium .

Distribution. Western Atlantic: North Carolina (Coutère 1909; J.E. Duffy unpublished); Cuba (Martínez Iglesias and García Raso 1999); Jamaica (Coutère 1909); Virgin Islands ( Chace 1972); Gulf of Mexico (Coutère 1909; Dardeau 1984); Yucatan peninsula (Coutère 1909; Chace 1972); Belize Barrier Reef (this study); Windward Islands ( Chace 1972); Tobago ( Chace 1972); Curacao (Coutère 1909); Brazil ( Christoffersen 1979). With the discovery of several new species closely related to Z. longicarpus ( Table 1), the geographical boundaries of previous records under this name should be treated with caution.

Remarks. We have found only a very few specimens of this species in Belize. In Belizean specimens of Spheciospongia vesparium , for example, Z. dardeaui n. sp. is the more common large species of the genus and appears to “take the place” of Z. longicarpus , cohabiting in that sponge with Z. brooksi and Z. pectiniger , as Z. longicarpus does elsewhere. Z. longicarpus may be distinguished from the several other, morphologically similar species by the slender orbital hoods, reduced cardiac notch, relatively small spines on the dorsal surface of the telson, and apical insertion of the spine overhanging the dactylar articulation on the major cheliped ( Table 1).

Z. longicarpus and related species are among the largest and most common species of Zuzalpheus in shallow waters of the western Atlantic, so it is not surprising that the name has been widely used in the literature. Yet, because the holotype designation is problematic, the history of the name is truly a quagmire. Herrick (1891:385) described the larvae of several species of Alpheidae , recognizing at least two varieties in what he called Alpheus saulcyi Guérin , but he refers to types only in his table 1, wherein he registers his specimen number 13 as the type of his variety longicarpus , but does not mention its inclusion in any Museum collection. Coutière (1898a) had access to abundant material of this species, including two typical specimens sent by Herrick. In that brief contribution, Coutière (1898a) published the first inclusion of the species in the genus Synalpheus , and also provided dorsal views of the anterior regions of four shrimp, two of which (his Figs. 2 ” and 2’”) represent the first known illustrations of S. longicarpus . Coutière additionally established the identity of this taxon in his magnum opus (1899), which includes an illustration of a mandible from a type (his Fig. 153), an antennule and the minor first chela of a cotype (his Figs. 116, 123, and 241), and the tip of the telson from another specimen (his Fig. 394).

Although Coutière (1907) first published the binomen Synalpheus longicarpus , the species was defined later in his monograph of the American species belonging in that genus ( Coutière 1909), wherein a useful diagnosis is included along with figures that have been repeatedly reproduced ( Hay and Shore 1918; Verrill 1922; Williams 1965 and 1984).

Probably overwhelmed by the striking and apparently continuous intraspecific variation in the abundant material that he examined, Christoffersen (1979) decided to include S. pandionis (Coutière) as a junior syn- onym of S. longicarpus . S. pandionis was then resurrected by Dardeau (1984), and Christoffersen (1998) later accepted Dardeau’s conclusions. Interestingly, in the figures provided both by Christoffersen (1979) and Dardeau (1984), it is possible to recognize some of their specimens as a different species (see remarks under Zuzalpheus dardeaui , n. sp.), as is also the case of the SEM photographs of Ray (1974). The “ Synalpheus longicarpus ” depicted in plate 65 from Boone (1930) is clearly a misidentification since that specimen is lacking the comb of setae on the extensor surface of the dactyl of the smaller chela, and the uropodal exopods are barren of teeth.

Additional details on the taxonomic history of this species can be found in the general introduction of Coutière’s (1909) revision of Synalpheus , and in Verrill (1922). Dardeau (1984:73) could not locate the holotype, and the cotypes mentioned by Coutière (1899) are the only type material that might still be extant. Designation of a neotype is beyond the scope of the present contribution, mainly because of the difficulty of proving the nonexistence of the holotype or trying to find the cotypes.

Figures

FIGURE 2. Zuzalpheus brevifrons (Chace 1972). Male 3.2 mm (VIMS 95CBC3501): lateral view of abdomen. Scale bar = 1mm.

FIGURE 23. Zuzalpheus longicarpus (Herrick 1891). Male 7.6 mm (USNM 1019063): a, anterior region of carapace and cephalic appendages, dorsal view; b, same, tilted lateral view; e, abdomen, lateral view; f, telson and uropods, dorsal view; g, detail of left uropod, dorsal view. Ovigerous female 7.3 mm (USNM 1019063): c, chela of major first pereopod, lateral view; d, same, tip of fixed finger, ventral view. Scale bar = 1 mm for a, b, f, 1.4 mm for c, d, e, and 0.74 mm for g.