Zuzalpheus idios, Rios & Duffy, 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 : 36-40

Zuzalpheus idios , n. sp.

( Figs. 13–17 , Plate 3 )

Synalpheus sp.3 , new species Ríos 2003:91, figures 2–12 through 2–16, plate II.

Synalpheus “brooksi D”: Morrison et al. 2004; Macdonald et al. 2006

Material examined. ( 1) Holotype ♂ ( USNM 1019047 , VIMS 01CBC8007), 5.0 mm, allotype ovigerous ♀ ( USNM 1019048 , VIMS 01CBC8006), 5.1 mm; paratypes: 2 ♂ ( USNM 1019049 , VIMS 01CBC8007), 4.3 and 4.7 mm, Carrie Bow Cay , Belize, 4 May 2001, in demosponge Hymeniacidon amphilecta , 6m.

(2) 3 ovigerous ♀ ( VIMS 90 CBC0205, 90CBC0208, 90CBC0213) 3.3–4.4 mm, 6 ♂ ( VIMS 90 CBC0209– 90CBC0215), 3.4–4.3 mm, outer ridge at Carrie Bow Cay , Belize, 6 December 1990, in Hymeniacidon amphilecta , 17 m.

(3) 1 ovigerous ♀ ( VIMS 93 CBC7601), 4.7 mm, 2 ♂ ( VIMS 93 CBC7603, 93CBC7604), 4.4 and 3.2 mm, spur and groove reef at Carrie Bow Cay , Belize, 5 April 1993, in Hymeniacidon amphilecta , 9 m.

(4) 1 ovigerous ♀ ( VIMS 93 P5011), 4.4 mm, 3 ♂ ( VIMS 93 P5012–93P5014), 4.0– 4.6 mm, from a larger colony, Cayos Limones , San Blas Islands, Panama, 4 October 1993, in Lissodendoryx colombiensis , 12 m.

Description of holotype. Body subcylindrical; carapace smooth, sparsely setose, with pterygostomian corner produced into bluntly acute angle, and posterior margin with cardiac notch distinct. Rostrum about as long as ocular hoods, but distinctly narrower, distally upturned; margins in dorsal view straight. Orbitorostral process absent. Ocular hoods dorsally convex; in dorsal view, bluntly acute, separated from rostrum by deep adrostral sinus. Ocular process triangular, flanged posteriorly onto lower side of eye. Ocellary beak in lateral view not rod-like, broader at base. Stylocerite acute, but tip blunt; mesial margin slightly concave; surpassing midpoint of first segment; latter without ventromesial tooth, and with two basal ventral processes. Basicerite without spine on dorsolateral corner, and with longer ventrolateral spine reaching distal half of second segment of antennular peduncle. Scaphocerite blade absent, acute lateral spine robust, with lateral margin slightly concave, slightly surpassing basicerite spine, not 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. Remaining mouthparts as figured.

Major pereopod 1 massive, fingers clearly shorter than half length of palm; fixed finger slightly shorter than dactyl; in ventral view, outer face of fixed finger without any marked lateral protuberance. Palm of chela with distal superior margin produced into tapering conical blunt tubercle not conspicuously directed upward; in frontal view, tubercle does not show ventral surface and does not rise above palmar profile. Merus, extensor margin strongly convex, ending in obtuse angle.

Minor pereopod 1 with palm clearly less than two times longer than high; fingers clearly shorter than palm; dactyl with flexor margin straight, blade-like, with 2 distinct 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, and 2 distinct teeth subequal in length. Extensor margin of merus convex, ending in right angle.

Pereopod 2 with carpus 5-segmented, subequal to merus.

Pereopod 3 slender; dactyl biunguiculate, with flexor tooth clearly thicker than extensor; propodus with row of 7 mobile spines on flexor margin and one pair of distal mobile spines flanking base of dactylus; carpus with distal mobile spine on flexor margin; merus almost 4 times longer than wide, without movable spines on flexor margin; mesial lamella on coxa present. Pereopod 4 similar to third, slightly weaker. Pereopod 5 weaker than fourth; propodus with only 2 spines on flexor margin, and 5 transverse combs of stout setae on ventral face; carpus without distal spine.

Pleura 1 of male with posterior corner distinctly produced ventrally and anteriorly into small hook; sec- ond pleura of male broadly rounded; third to fifth pleura of male progressively acute, but not pointed. Pleopod 1 of male, with 6 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 with central space between distal spines about one-third of distal margin; marginal convex lobe present; posterior corners adjacent to spines obtuse. Anal flaps, perianal setae, and postanal setal brush absent. Uropods with a single fixed tooth on outer margin of exopod distinctly removed from the mobile one, this latter slightly longer and more slender than adjacent inner fixed tooth.

Color ( Plate 3 ). Specimens from Hymeniacidon amphilecta have a milky translucent appearance with regularly scattered red chromatophores on the carapace and major chela; cutting edges on fingers of major chela amber, distal palm and fingers of major chela orange. Developing eggs and ovaries deep scarlet to brick-red to brownish-orange. Specimens from Lissodendoryx colombiensis in Panama were mostly transparent with scattered contracted chromatophores, and had a light purple hue most apparent in smaller specimens, also with dark red ovaries and eggs.

Etymology. From the Greek, meaning “one’s own” or “pertaining to oneself”. The name signifies the distinctiveness of this species despite its strong resemblance to Z. brooksi .

Variation. In some males, the abdominal pleura posterior to the second one form an acute angle ventrally, without prolonging into an acuminate projection. Some juveniles have 4 segments in the carpus of the second pereopod, while occasional larger specimens have six. Arrangement of teeth on the uropodal exopod is constant, except in small juveniles where the external tooth has the appearance of being not fully developed.

Hosts and ecology. Zuzalpheus idios , n. sp., lives in groups of up to several tens of specimens with numerous ovigerous females and juveniles present. It inhabits canals of the demosponges Hymeniacidon amphilecta in Belize and Lissodendoryx colombiensis in Panama.

Distribution. Belize Barrier Reef (this study), San Blas Islands, Panama (J.E. Duffy unpublished), possibly Florida Keys, USA (J.E. Duffy unpublished).

Remarks. The differences in host association between this species and Z. brooksi (Coutière) are supported by a subtle suite of morphological characters. In Z. idios , the conical projection overhanging the base of the dactyl in the major chela is slightly blunter and oriented more directly anteriorly, as opposed to upwardly in Z. brooksi . Also, Zuzalpheus idios , n. sp., grows to slightly larger sizes than Z. brooksi . Its color in life is quite distinct from that of Z. brooksi .

Figures

PLATE 3. Zuzalpheus filidigitus, female (VIMS 01CBC0901) from Xestospongia cf. proxima, Curlew Reef, Belize. Zuzalpheus herricki, female (VIMS 05FK0602) from Hippospongia sp., Tavernier Key, Florida, USA. Zuzalpheus goodei, female (VIMS 03CBC3701) from Pachypellina podatypa, Sand Bores, Belize. Zuzalpheus goodei, male (VIMS 03CBC3702) from Pachypellina podatypa, Sand Bores, Belize. Zuzalpheus idios, female (VIMS 01CBC8001) from Hymeniacidon amphilecta, Carrie Bow Cay, Belize. Zuzalpheus kensleyi, female (VIMS 01CBC3802) from unidentified yellow sponge, Sand Bores, Belize.

FIGURE 13. Zuzalpheus idios, n. sp. Allotype ovigerous female 5.1 mm (USNM 1019048): a, anterior region of carapace and cephalic appendages, dorsal view; b, same, lateral view; c, telson and uropods, dorsal view. Scale bar = 1 mm for a, b; and 0.76 mm for c.

FIGURE 14. Zuzalpheus idios, n. sp. Allotype ovigerous female 5.1 mm (USNM 1019048): a, chela of major first pereopod in lateral view; b, same, anterior region alternate lateral view; c, same, dorsal view; d, same, tip of fixed finger, ventral view. Paratype male 4.7 mm (USNM 1019049): e, minor first pereopod, lateral view; f, distal portion of same, alternate lateral view. Scale bar = 1 mm for a, b, c, d; 1.2 mm for e; and, 0.24 mm for f.

FIGURE 15. Zuzalpheus idios, n. sp. Mouthparts. Paratype male 4.7 mm (USNM 1019049): a, mandible; b, first maxilla; c, second maxilla; d, first maxilliped; e, second maxilliped; f, third maxilliped; g, same, detail of tip. Scale bar = 0.5 mm for a, b,c, d, e; 1 mm for f; and 0.2 mm for g.

FIGURE 16. Zuzalpheus idios, n. sp. Paratype male 4.7 mm (USNM 1019049): a, third pereopod; b, same, detail of distal portion; c, fourth pereopod; d, same, detail of distal portion; e, fifth pereopod; f, detail of distal portion; g, second pereopod. Scale bar = 1 mm for a, c, e, g; and 0.2 mm for b, d, f.

FIGURE 17. Zuzalpheus idios, n. sp. Holotype male 5.0 mm (USNM 1019047): a, abdomen, lateral view. Paratype male 4.3 mm (USNM 1019049): b, detail of first abdominal pleura, lateral view. Paratype male 4.7 mm (VIMS 01CBC8007): c, detail of first abdominal pleura, lateral view; d, first pleopod, lateral view; e, same, detail of Appendix interna; f, second pleopod, lateral view. Allotype ovigerous female 5.1 mm (USNM 1019048): g, abdomen, lateral view; h, first pleopod, lateral view; i, second pleopod, lateral view. Scale bar = 1 mm for d, f; 1.3 mm for b, c; 1.5 mm for h, i; 3 mm for a, g; and 0.3 mm for e.