Zuzalpheus yano, 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 : 69-74

Zuzalpheus yano , n. sp.

( Figures 31–34 , Plate 5 )

Synalpheus sp. 6 , new species Ríos 2003:155, figures 2–30 through 2–33.

Synalpheus “ pandionis small” Morrison et al. 2004.

Material examined. ( 1) Holotype ♂, 6.0 mm ( USNM 1019055 , VIMS 01CBC7402), allotype ovigerous ♀, 7.2 mm ( USNM 1019056 , VIMS 01CBC7401), Twin Cays , Belize, 26 April 2001 in Lissodendoryx colombiensis , 1–2 m.

(2) Paratypes: 1 ♂ ( USNM 1019057 , VIMS 94CBC14-14), 5.3 mm, Twin Cays , Belize, 20 August 1994, in Lissodendoryx colombiensis , 1– 2 m . 1 ovigerous ♀ ( USNM 1019058 , VIMS 94CBC24-07), 5.5 mm, Twin Cays , Belize, 22 August 1994, in Lissodendoryx colombiensis , 1– 2 m .

(3) 1 ovigerous ♀ ( VIMS 94 CBC1407), 6.4 mm, Twin Cays , Belize, 20 August 1994, in Lissodendoryx colombiensis , 1–2 m.

(4) 1 ♂ ( VIMS 98 CBC0902), 5.0 mm, 1 ovigerous ♀ ( VIMS 98 CBC0901), 5.4 mm, Sand Bores , Belize, 3 December 1998, in Lissodendoryx cf. strongylata , 1.5 m deep .

(5) 1 ovigerous ♀ ( VIMS 93 CBC6302), 5.3 mm, 1 ♂ ( VIMS 93 CBC6305), 4.6 mm, Sand Bores , Belize, 31 March 1993, in unidentified yellow tube sponge, 2 m.

Description of holotype. Body subcylindrical; carapace smooth, with scattered short setae; pterygostomian corner produced into blunt acute angle, and posterior margin with cardiac notch distinct. Rostrum lanceolate, slightly upturned and laterally compressed; narrower, but about as long as orbital hoods; these latter dorsally convex with flattened mesial slope wider than lateral edge, and converging under base of rostrum; in dorsal view, ocular hoods squared off and blunt anteriorly, margins convex, separated from rostrum by deep adrostral sinus. Ocular processes conspicuously broad. Ocellary beak in lateral view, broad. Stylocerite slen- der; mesial margin slightly concave; tip acute; reaching nearly as far as distal margin of first antennular peduncle; this latter segment without ventromesial tooth, and with 2 basal ventral processes. Basicerite with dorsolateral corner slightly produced into blunt acute angle; longer ventrolateral spine clearly overreaching tip of stylocerite. Scaphocerite blade totally absent, acute lateral spine robust, with lateral margin slightly con- cave, barely overreaching antennular peduncle, and reaching slightly shorter than basicerite lateral spine; mesial projection at base of scaphocerite present. Maxilliped 3 with distal circlet of spines on distal segment, and without ventrodistal spine on antepenultimate segment; remaining mouthparts as figured.

Major pereopod 1 massive, fingers shorter than half length of palm; fixed finger somewhat shorter than dactyl; in ventral view, outer face of fixed finger without any pronounced protuberance. Palm of chela with distal superior margin produced into prominent tubercle with downwardly directed acute spine on its ventral surface. Merus, extensor margin strongly convex, with distal angular projection.

Minor pereopod 1 with palm about 2 times longer than high; fingers clearly shorter than palm; dactyl with flexor margin straight, blade-like, with 2 distinct but unequal terminal teeth oriented parallel to dactyl axis; transverse dorsal setal combs on extensor surface of dactyl very conspicuous; fixed finger with flexor surface obliquely concave, and subdistal accessory bump. Extensor margin of merus convex, ending in right angle.

Pereopod 2 with carpus 5-segmented, distinctly longer than merus.

Pereopod 3 stout; dactyl biunguiculate, with flexor tooth thicker than extensor tooth; propodus of right leg with row of 8 (left leg with 9) mobile spines on lower margin and one pair on distal end; carpus with one mobile distal spine on flexor margin; merus without spines on flexor margin; mesial lamella on coxa present. Pereopod 4 similar to third, but weaker. Pereopod 5 similar to fourth but slender, with 12 parallel rows of transverse setal combs, 3 mobile spines, and 1 distal pair of mobile spines on ventral face of propodus; carpus without distal spine.

Pleura 1 of male with posterior corner distinctly produced ventrally into anteriorly directed hook; second to fourth pleura of male with lower margin produced into acute angle; fifth pleura similar but more blunt. Pleopod 1 of male, with 8 terminal setae on endopod; second pleopod of male with marginal setae on exopod originating close to base on external margin; appendix interna on second to fifth male pleopods, present. Telson, space between distal spines about one-third of distal margin; marginal convex lobe absent; posterior corners adjacent to spines not produced. Anal flaps, perianal setae, and postanal setal brush absent. Uropods with 5 fixed teeth on outer margin of exopod.

Color ( Plate 5 ). Dull orange-brown to reddish in overall appearance, with brown tips of the major first chela. This latter feature was still evident in some preserved specimens as a translucent fringe. Ovaries and embryos are brick-red.

Etymology. The specific name is a Mayan word for "another" or "different" and was chosen to underscore the fact that this is yet another new species of Zuzalpheus in the complex related to Z. pandionis .

Variations. The number of fixed teeth on the outer margin of the uropodal exopod varies from 4 to 6, rarely 3 or 7, but the most frequent number is 5.

Hosts and ecology. We have found this species most frequently within the sponge Lissodendoryx colombiensis . Other occasional hosts include the sponges Hymeniacidon caerulea , Pachypellina podatypa , and an unidentified yellow sponge.

Distribution. Western Atlantic: Belize (this study), Bocas del Toro region, Panama (JED, pers. obs.).

Remarks. There is considerable morphological similarity between Z. yano , n. sp., and a group of species that includes Z. longicarpus and Z. pandionis ( Table 1). Z. yano most closely resembles Z. ul, n. sp., which preferentially inhabits Hymeniacidon caerulea . However, Z. yano , n. sp., attains larger sizes, never has any trace of a blade on the scaphocerite, and has the second to fourth male pleurae more pointed.

Coutière (1909) erected Synalpheus grampusi for a group of specimens that resemble Z. yano , n. sp., but after examining the type series we are confident in erecting a new species. In the description of S. grampusi, Coutière (1909) recognized several diagnostic characters also present in Z. yano , n. sp., most notably the rounded ocular hoods, the shape of the chelae, the fixed teeth on the uropod, and the absence of a blade on the scaphocerite. However, the two largest syntypes (USNM 38399) of S. grampusi have a blade on the scaphocerite, which is why Chace (1972) decided to synonymize it with S. pandionis (see remarks under this species). Coutière (1909) called “anomalous” the specimen depicted in his figure 36a, and it is this illustration that most strongly resembles both his description of S. grampusi and Z. yano , n. sp., Chace (1972) suspected that the type series of S. grampusi includes a mixture of taxa, and suggested that “a new name might have to be assigned” for S. grampusi if proven valid. Furthermore, according to Article 72.4.1 of the International Code of Zoological Nomenclature ( ICZN 1999), since Coutière (1909) referred to the specimens without blade as "anomalous", they should not be considered as syntypes. Consequently the only appropriate namebearing specimens are those with a blade, i. e. the pair of largest specimens in lot USNM 38399, but the third specimen in the lot (a smaller ovigerous female without blade) is not a real syntype. We conclude that trying to conserve the name “ Synalpheus grampusi ” would only further confuse the taxonomy of the group.

Figures

PLATE 5. Zuzalpheus sanctithomae, female (VIMS 01CBC6001) from Hymeniacidon caerulea, Sand Bores, Belize. Zuzalpheus williamsi, female from Hymeniacidon caereulea. Zuzalpheus ul, female (VIMS 01CBC4002) from Hymeniacidon caereulea, Sand Bores, Belize. Zuzalpheus ul, male (VIMS 01CBC4001) from Hymeniacidon caerulea, Sand Bores, Belize. Zuzalpheus yano, female (VIMS 03P2401) from Lissodendoryx colombiensis, Isla Pastores, Bocas del Toro region, Panama. Zuzalpheus yano, female (VIMS 03P2401) from Lissodendoryx colombiensis, Isla Pastores, Bocas del Toro region, Panama. Zuzalpheus yano, male (VIMS 03P2403) from Lissodendoryx colombiensis, Isla Pastores, Bocas del Toro region, Panama.

FIGURE 31. Zuzalpheus yano, n. sp. Paratype male 5.3 mm (USNM 1019057): a, anterior region of carapace and cephalic appendages, dorsal view; b, same, lateral view; c, abdomen, lateral view; d, minor first pereopod, lateral view; e, chela of same, alternate lateral view. Paratype ovigerous female 5.5 mm (USNM 1019058): f, abdomen showing two eggs, lateral view. Scale bar = 1.4 mm for a, b, and 1 mm for c, d, e, f.

FIGURE 32. Zuzalpheus yano, n. sp. Paratype male 5.3 mm (USNM 1019057): a, chela of major first pereopod, lateral view; b, same, detail of distal portion, alternate lateral view; c, same, tip of fixed finger, ventral view; d, left second pereopod, lateral view; e, telson and uropods, dorsal view. Scale bar = 1 mm for a, b, 0.7 mm for c, e, and 0.6 for d.

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.

FIGURE 34. Zuzalpheus yano, n. sp. Mouthparts. Paratype male 5.3 mm (USNM 1019057): a, right mandible; b, right first maxilla; c, right second maxilla; d, right first maxilliped; e, right second maxilliped; f, right third maxilliped; g, same, detail of distal portion, alternate lateral view. Scale bar = 1 mm for a, b, c, d, e, 2 mm for f, and 0.5 mm for g.