Zuzalpheus ruetzleri ( Macdonald and Duffy 2006 ) 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 : 61-62

Zuzalpheus ruetzleri ( Macdonald and Duffy 2006) n. comb.

( Plate 4 )

Synalpheus “ bousfieldi blade”, in Morrison et al., 2004, and in Macdonald et al., 2005.

Material examined. ( 1) Holotype: ♂, ( USNM 1092312 , VIMS 01CBC4502), 3.6 mm, Sand Bores , Belize, 30 April 2001, in Hymeniacidon cf. caerulea , 1–2 m.

( 2) Allotype: ♀, ( USNM 1092313 , VIMS 01CBC4501), 4.1 mm, Sand Bores , Belize, 30 April 2001, in same individual H. cf. caerulea as holotype.

(3) Paratypes. 1 ♂ ( USNM 1092314 , original VIMS 01CBC6101), 3.1 mm, Sand Bores , Belize, 2 May 2001, in H. cf. caerulea , 1– 2 m . 2 ♀ ( USNM 1092315 , VIMS 01CBC5601, 01CBC5602), 3.5 mm, 3.2 mm, Sand Bores , Belize, 2 May 2001, in H. cf. caerulea , 1– 2 m . 1 ♀ ( AMNH 18494 , VIMS 01CBC6301), 4.4 mm, Sand Bores , Belize, 2 May 2001, in H. cf. caerulea , 1– 2 m . 1 ♂ ( USNM 1092316 , VIMS 01CBC6302), 4.0 mm, Sand Bores , Belize, in same H. cf. caerulea as VIMS 01CBC6301 .

Diagnosis. Body subcylindrical; carapace smooth, sparsely setose, with pterygostomian corner produced into bluntly acute angle, and posterior margin with cardiac notch distinct. Rostrum longer than orbital teeth, and slightly 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. Stylocerite acute, with blunt tip; mesial margin concave; surpassing midpoint of first segment of antennular peduncle; latter without ventromesial tooth, with two basal ventral processes. Basicerite with dorsomesial corner rounded, lateral spine reaching distal half of third segment of antennular peduncle. Scaphocerite with well-developed blade, reaching to almost half length of lateral spine; acute lateral spine robust, slightly surpassing basicerite spine, slightly overreaching antennular peduncle; mesial projection at base of scaphocerite present. Maxilliped 3 with distal circlet of spines on distal segment, without ventrodistal spine on antepenultimate segment.

Major pereopod 1 massive, fingers clearly less than half length of palm; fixed finger slightly shorter than dactyl. Palm of chela with distal superior margin forming a protuberance, which is secondarily produced distally, slightly curved downward, toward dactyl.

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 dactyl very conspicuous; fixed finger with flexor margin straight, blade-like, and 2 distinct distal teeth subequal in length.

Pereopod 2 with carpus 5-segmented, subequal to merus. Both fingers terminating in narrow, curved tooth.

Pereopod 3 slender; dactyl biunguiculate, with flexor tooth clearly thicker than extensor tooth; mesial lamella on coxa present. Pereopods 4 and 5 normal.

Pleura 1 of male with posterior corner distinctly produced ventrally into small, anteriorly directed hook; second pleura of male broadly rounded; third to fifth pleura of male progressively acute, but not pointed. Pleopod 1 of male, with 2 terminal setae on endopod; second pleopod of male with marginal setae on exopod originating in distal 1/2; appendix interna present on second to fifth male pleopods. Telson with marginal convex lobe; 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, which is longer and more slender than adjacent inner fixed tooth.

Color ( Plate 4 ). Non-descript, translucent with dull gold tinge to thickened parts of cuticle; distal palm and fingers of major chela brownish; ovaries and eggs pale pink to olive green to chestnut brown.

Variation. The length of the scaphocerite blade ranges from1/3 to 2/3 length of lateral spine of scaphocerite. The relative length of the distal teeth on the fingers of the minor first pereopod also vary, with the distal tooth larger than the proximal tooth in some specimens, while in others the teeth are subequal.

Hosts and ecology. In Belize, Zuzalpheus ruetzleri appears to be a specialist on the cryptic midnight-blue sponge Hymeniacidon cf. caerulea . It is almost invariably found as a single heterosexual pair within a sponge.

Distribution. San Blas Islands, Panama ( Macdonald and Duffy 2006), Belize Barrier Reef ( Macdonald and Duffy 2006; this study).

Remarks. Zuzalpheus ruetzleri belongs to the complex of morphologically similar species that includes Z. brooksi , Z. bousfieldi and Z. chacei . Z. ruetzleri is similar in color pattern to Z. bousfieldi , which also can inhabit H. cf. caerulea , making identification practical only with a microscope. However, the presence of a blade on the scaphocerite is a remarkably consistent character differentiating these two species, and the two morphological types (bladed and unbladed) appear to mate assortatively.

Figures

PLATE 4. Zuzalpheus pandionis, female (VIMS 03CBC1701) from Lissodendoryx sp., Carrie Bow Cay, Belize. Zuzalpheus paraneptunus, female (VIMS 01CBC0704) from Oceanapia sp., Curlew Reef, Belize. Zuzalpheus pectiniger, female (VIMS 05FK1501) from Spheciospongia vesparium, Key Largo, Florida, USA. Zuzalpheus pectiniger, male (VIMS 05FK1502) from Spheciospongia vesparium, Key Largo, Florida, USA. Zuzalpheus regalis, female (VIMS 01CBC02) from Xestospongia cf. subtriangularis, Curlew Reef, Belize. Zuzalpheus ruetzleri, female (VIMS 01CBC6301) from Hymeniacidon caerulea, Sand Bores, Belize.