Zuzalpheus mcclendoni ( Coutière, 1910 ) 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 : 50-52

Zuzalpheus mcclendoni ( Coutière, 1910) n. comb.

Synalpheus mcclendoni Coutière, 1910:487 , fig. 3; Chace 1972:95, figs. 33, 34; Ray 1974:148, fig. 133–135; Ríos 2003:124–128.

Synalpheus macclendoni Dardeau 1984: 74 , fig. 37–39.

Material examined. (1) 1 ♂, 3.2 mm ( USNM 1019064 , VIMS 93CBC7701), Carrie Bow Cay , Belize, 5 April 1993, in unidentified yellow boring sponge, 2.5 m .

(2) 1 ♂ ( VIMS 94 CBC3402), 2.5 mm, outer ridge at Carrie Bow Cay , Belize, 23 August 1994, no host found, 17 m .

(3) 1 ♂ ( VIMS 93 CBC3205), 2.5 mm, fore-reef slope, Carrie Bow Cay , Belize, 22 March 1993, in Agelas clathrodes , 22 m .

(4) 1 ♂ ( VIMS 93 CBC6103), outer ridge at Carrie Bow Cay , Belize, 29 March 1993, in unidentified columnar mustard-colored sponge, 14 m .

(5) 2 ♂ ( VIMS 93 CBC7402), fore-reef slope, Carrie Bow Cay , Belize, 31 March 1993, in Agelas clathrodes , 22 m .

Diagnosis. Body subcylindrical; carapace smooth, glabrous, with pterygostomian corner forming obtuse angle, and posterior margin with cardiac notch distinct. Rostrum triangular, somewhat narrower and slightly longer than ocular hoods, not conspicuously upturned, and sometimes with a shallow ventral convex keel behind the base. Orbitorostral process absent. Ocular hoods dorsally convex; in dorsal view, acute, separated from rostrum by deep adrostral sinus. Ocular process small, but prolonged backwards into distinct keel on mesioventral edge of eye. Ocellary beak in lateral view rectangular. Stylocerite strong; mesial margin slightly concave; tip blunt; slightly overreaching distal margin of first segment of antennular peduncle; this latter segment with ventromesial tooth, and with two basal ventral processes. Basicerite with superior corner not prolonged and with long ventrolateral spine slightly overreaching tip of stylocerite. Scaphocerite blade present, longer acute lateral spine robust, clearly overreaching 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, chela elongated, fingers about half length of palm, flattened, curved inwards, and tips crossing; in ventral view, outer face of fixed finger without any protuberance. Palm of chela with distal superior margin typically tapering into strong acute spine. Merus, extensor margin strongly convex, with distal flat angular projection.

Minor pereopod 1 with palm about twice as long as high; fingers shorter than palm; dactyl with flexor margin blade-like, subdistal accessory tooth, and two bumps, in addition to distal tip; transverse dorsal setal combs on extensor surface of dactyl very conspicuous; fixed finger with flexor surface blade-like, and subdistal bump in addition to distal tip. Extensor margin of merus slightly convex, ending in right angle.

Pereopod 2 with carpus 5-segmented, about as long as merus.

Pereopod 3 slender; dactyl biunguiculate, with flexor tooth thicker than extensor; merus without spines; mesial lamella on coxa present. Pereopods 4 and 5 normal.

Pleura 1 of male with posterior corner obscurely produced ventrally and anteriorly into small hook-like tooth; second pleura of male broadly rounded. Pleopod 1 of male, with about four terminal setae on endopod; second pleopod of male with marginal setae on exopod originating near midpoint; appendix interna on second to fifth male pleopods, present. Telson, space between distal spines greater than one-third of distal margin; marginal convex lobe present; posterior corners adjacent to spines obtuse. Anal flaps, perianal setae, and postanal setal brush all absent. Uropods with a single fixed tooth on outer margin of exopod, about as strong as fixed inner tooth, but shorter than slender mobile spine.

Color. In Belizean specimens from Agelas clathrodes , the body was generally transparent; major chela bears a striking pattern of prominent red chromatophores on disto-dorsal surface of palm and flexor margins of fingers, and double transverse bands of dark blue pigment immediately proximal to the red area. We have also observed this distinctive color pattern in specimens from the same host in the San Blas islands of Panama and in the Florida Keys; they are presumably conspecific. In contrast, a single specimen from Panamá differed strikingly from these others in having an overall creamy uniform yellow to white background color with some yellowish wash on distal portions of the major chela; this presumably represents an undescribed species.

Variations. The ocular hoods are usually straight, but occasionally in some specimens they look as Ray (1974) remarked: "they show a slight inward curving with their inner surfaces slightly sloping mesoventrally". The stylocerite usually reaches the midpoint of the second segment of the antennular peduncle, but sometimes it barely overreaches the first segment, as in Figure 3n of Coutière (1910) and Figure 33b of Chace (1972). The superior border of the palm of the major chela typically tapers into a streamlined point, but in a couple of individuals there was a basal constriction on the distal spine.

One male from Panama had two major chelae on the first pair of pereopods. To our knowledge this is the only record of this kind of abnormal symmetry in any species of Zuzalpheus . Females with two minor chelae are typical in some of the eusocial species, such as Z. filidigitus ( Duffy 1998; Duffy and Macdonald 1999).

Hosts and ecology. Z. mcclendoni is uncommon in our collections from Belize. We have found several single specimens in Agelas clathodes , one specimen in an unidentified yellowish boring sponge lining smooth cylindrical canals in coral rock, and a few specimens unassociated with hosts, presumably dislodged from them during rubble collection.

Distribution. Western Atlantic: Dry Tortugas, Florida, USA ( Coutière 1910), Florida Keys, USA (J.E. Duffy unpublished); Bahamas ( Dardeau 1984); Cuba (Martínez Iglesias and García Raso 1999); St. Lucia, Tobago Cays, and Yucatan peninsula of Mexico ( Chace 1972); San Blas Islands, Panamá ( Duffy 1992), Belize Barrier Reef (this study).

Remarks. Recognizing its similarity to Z. sanctithomae, Coutière (1910) erected Synalpheus mcclendoni succinctly, restricting his description to a few characters that would distinguish the two species, and including only five illustrations. Chace (1972) further complemented the knowledge of this species with a full set of drawings, but, in what appears to be a mere typographical error, his key to the species introduced an unfortunate misunderstanding. In couplet 9 of his key to Synalpheus, Chace (1972) separated S. mcclendoni from S. sanctithomae , among other characters, on the basis of the shape of the major chela, which he stated is "not noticeably twisted" in S. mcclendoni and "twisted" in S. sanctithomae . In fact, the opposite is true. Coutière (1910) explicitly mentioned that the fingers of the major chela are curved inwards in S. mcclendoni , and this is what gives the chela the twisted appearance noted by Chace (1972). Ray (1974) gave an extended diagnosis of S. mcclendoni , mentioning the inward curvature of the fingers of the major chela, and provided SEM images illustrating it. Dardeau (1984) perpetuated the confusion by misspelling the specific name as " mac- clendoni ", and including Chace’s mistaken couplet in his key. Ironically, the specimens Dardeau (1984) designated with the incorrect spelling may belong to an undescribed species: he mentioned that the material he examined, syntypes included, differ from the specimens studied by Chace (1972) in the form of the palmar spine on the major chela and the first pleura of males. Both of these characters are variable in Z. mcclendoni , but other details, such as color and host preferences, suggest that there is indeed a second species. The question of which of the species should retain the name mcclendoni awaits a closer examination of the type material deposited in the USNM. Notably, figure 3n in Coutierè (1910) depicts a scaphocerite shorter than the ones we observed, which were more similar to figure 33b in Chace (1972).

At Carrie Bow Cay we have collected an undescribed species morphologically very similar to Z. mcclendoni , but with a strikingly different color pattern (blue, white and red) on the major chela. Coinciding with most of the specimens examined by Dardeau (1984), these shrimp were living inside a sponge in the genus Agelas .

Figures

FIGURE 3. Zuzalpheus dardeaui, n. sp. Paratype female 9.1 mm (USNM 1019041): a, anterior region of carapace and cephalic appendages, dorsal view; b, same, lateral view. Paratype male 7.6 mm (USNM 1019040): c, abdomen, lateral view. Paratype ovigerous female 9.2 mm (USNM 1019040): d, abdomen, lateral view. Allotype ovigerous female 9.9 mm (USNM 1019039): e, abdomen, lateral view. Paratype male 8.2 mm (VIMS 01CBC7408): f, detail of 4th–6th abdominal pleurae, lateral view. Scale bar = 1 mm for a, b; 2 mm for c, d; 2.5 mm for e; and 1.2 mm for f.

FIGURE 33. Zuzalpheus yano, n. sp. Paratype male 5.3 mm (USNM 1019057): a, right third pereopod; b, same, detail of distal portion; c, right fourth pereopod; d, same, detail of distal portion; e, right fifth pereopod; f, same, detail of distal portion; g, right first pleopod; h, same, detail of distal portion of endopod; i, right second pleopod. Scale bar = 1 mm for a, c, e, 0.4 mm for b, d, f, 0.8 for g, i, and 2 mm for h.