Synalpheus thele Iii, Hultgren & Duffy, 2009, n. sp.
Creators: name: Iii, Kenneth S Macdonald
name: Hultgren, Kristin
name: Duffy, Emmett
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Synalpheus
Synalpheus thele

description: Synalpheus thele n. sp.
Figures 22–27, Color plate 5C, D
Material examined. Jamaica: Holotype: non-ovigerous individual, CL: 2.93 mm, (USNM 1126373, original VIMS 08JAM891402), Columbus Park, Discovery Bay, (18° 27.955' N, 77° 24.843' W), from canals of Agelas cf. clathrodes Schmidt, 1870. Allotype: ovigerous female, CL: 3.32 mm, (USNM 1126374, original VIMS 08JAM891401), Columbus Park, Discovery Bay, from canals of same individual A. cf. clathrodes as holotype. Paratypes: 17 non-ovigerous individuals, CL: 2.07-3.13 mm, 16 ovigerous females, CL: 3.01- 3.61, (USNM 1126375, 1126376, 1126377, 1126378, 1126379, 1126380, 1126381, 1126382, 1126383, original VIMS 08JAM89-0101,-0601,-20,-21,-1004,-1005,-1006,-1007,-1008; VIMS 08JAM89-06,-08,- 1002,-1003,-13,-14,-22,-23,-24), Columbus Park, Discovery Bay, from canals of same individual A. cf. clathrodes as holotype.
Non-types: non-ovigerous individual, ovigerous female (VIMS 08JAM4104,05), fore-reef (near M1 channel marker), Discovery Bay, from canals of A. cf. clathrodes. 12 non-ovigerous individuals, 8 ovigerous females (original VIMS 08JAM6103,08,11,15–21,26,27,30), Columbus Park, Discovery Bay, from canals of A. cf. clathrodes. 5 non-ovigerous individuals, 6 ovigerous females (VIMS 08JAM7801-08), wall off Rio Bueno, from canals of A. cf. clathrodes. MaxCL ovigerous female: 3.61 mm. MaxCL non-ovigerous individual: 3.13 mm.
Description. Body form subcylindrical; carapace smooth, posterior margin with cardiac notch distinct. Frontal margin shallow, rostrum slightly longer than ocular hood (Fig. 22, 23), distinctly narrower, distally upturned; margins in dorsal view, straight. Ocular hoods dorsally convex; in dorsal view, blunt, separated from rostrum by adrostral sinus. Stylocerite acute, with blunt tip; mesial margin straight; reaching midpoint of first segment of antennular peduncle. Basicerite without tooth on dorsomesial corner, with longer ventrolateral spine, reaching just beyond second segment of antennular peduncle, length ~85% of scaphocerite. Scaphocerite blade absent, acute lateral spine robust, with lateral and mesial margins slightly concave, reaching to midpoint of third segment of antennular peduncle. Third maxilliped (Fig. 24) with distal circlet of approximately six spines on distal segment, without ventrodistal spine on antepenultimate segment.
Major first pereopod (Fig. 22, 23) massive, fingers clearly shorter than half length of palm; fixed finger slightly shorter than dactyl. Palm of chela with distinct blunt distal superior margin protuberance.
Protuberance with hint of secondary tubercle emerging distally (Fig. 23). Minor first pereopod (Fig. 25) with palm clearly less than two times longer than high; fingers shorter than palm; dactyl with flexor margin concave, blade-like, with 2 distinct distal teeth, subequal in length; extensor surface of dactyl with two closely set longitudinal rows of curved setae (Fig. 25); fixed finger with flexor margin concave, blade-like, and 2 distinct distal teeth subequal in length, both longer than dactyl distal teeth.
Second pereopod (Fig. 24) with carpus 5-segmented, subequal in length to merus. Both fingers terminating in a narrow, curved tooth.
Third pereopod (Fig. 24) slender; dactyl biunguiculate, with both ungues subequal in thickness, mesial margin of flexor unguis straight; propodus with row of eight movable spines on flexor margin and one pair of distal movable spines flanking base of dactyl; carpus with distal movable spine on flexor margin; merus four times longer than wide, without movable spines on flexor margin. Fourth pereopod (Fig. 24) similar to third, slightly weaker; propodus with seven flexor margin spines. Fifth pereopod (Fig. 24) weaker than fourth; propodus with four spines on flexor margin, and six transverse combs of stout setae on ventral face; carpus without distal spine.
First pleura (Fig. 23) of male with posterior corner distinctly produced ventrally into small hook; second to fifth pleura of male ventral margin straight, anterior corner rounded, posterior corner subacute. First pleopod (Fig. 25) of male with three terminal setae on endopod; second pleopod of male with marginal setae on exopod originating in distal half; appendix interna present on second to fifth male pleopods. Second pleopod (Fig. 25) of female with marginal setae on exopod originating in distal third; appendix interna present on second to fifth female pleopods.
Telson (Fig. 21) with convex lobe present on distal margin; posterior corners adjacent to terminal spines obtuse. Dorsal spines, anterior pair close to lateral margin, posterior pair further removed. Posterior margin with six setae between two sets of spines, lateral spines 70% length of inner spines. Space between distal spines <30% of distal margin; distal margin ~25% width of proximal margin. Uropods with a single fixed tooth on lateral margin of exopod distinctly removed anteriorly from movable spine, the latter slightly longer and more slender than adjacent posterior fixed tooth.
Color in life. Nondescript, translucent with dull gold tinge to thickened parts of cuticle; distal palm and fingers of major chela gold/orange; ovaries and embryos grass green.
Etymology. We have named this new species using the Greek word for teat or nipple, after the shape of the protuberance of the major chela, the most distinguishing feature of S. thele (see Fig 23 C).
Variation. While a vast majority (28 of 31 examined here) of females examined had green embryos and ovaries (Color plate 5C), three individuals had embryos of a different color. One (08JAM8913) had embryos the color of burnt sienna, the second individual (08JAM8912) had olive embryos, and the third female (08JAM4105) carried pale, whitish embryos. The shape of the frontal margin is also variable: not only does the depth of the adrostral sinuses vary among individuals, the length of the rostrum also varies, from subequal to the ocular hoods to almost 2x the length of the ocular hoods (fig 27).
Hosts and ecology. Synalpheus thele, n. sp. has been found only in the canals of the common Caribbean sponge Agelas cf. clathrodes. It was found in approximately equal sex ratios, with individual sponges containing from a single pair up to 33 shrimp. Most S. thele found were coexisting in the host sponge with Synalpheus agelas, Synalpheus carpenteri, and sometimes Synalpheus mcclendoni Coutière, 1910.
Distribution. Jamaica (this study).
Remarks. Synalpheus thele n. sp. appears to be a member of the complex of closely related, morphologically similar species that includes S. brooksi, S. bousfieldi, S. chacei, S. corallinus n. sp., and S. plumosetosus n. sp. (see Table 3). Synalpheus thele most closely resembles S. chacei, sharing a shallow frontal margin, minor chela setal brush consisting of two parallel rows of setae, and a blunt protuberance on the major chela. Synalpheus thele is distinct from S. chacei in the grass-green embryo color, larger size, and in its habit of living in equal sex ratios as opposed to eusocial colonies as in S. chacei (Duffy 1998), and from all other members of the group in the shape of the large blunt major chela protuberance.
description: Published as part of Iii, Kenneth S Macdonald, Hultgren, Kristin & Duffy, Emmett, 2009, The sponge-dwelling snapping shrimps (Crustacea, Decapoda, Alpheidae, Synalpheus) of Discovery Bay, Jamaica, with descriptions of four new species, pp. 1-57 in Zootaxa 2199 on pages 43-50, DOI: 10.5281/zenodo.189568