Synalpheus duffyi, Anker, Arthur & Tóth, Eva, 2008

Anker, Arthur & Tóth, Eva, 2008, A preliminary revision of the Synalpheus paraneptunus Coutière, 1909 species complex (Crustacea: Decapoda: Alpheidae), Zootaxa 1915, pp. 1-28 : 8-11

Synalpheus duffyi n. sp.

( Figs. 4 , 5 , 14 A, B, 15A, B)

(?) Synalpheus paraneptunus small – Duffy, 2003: 229.

Type material. Panama, Caribbean coast. Holotype, breeding female (queen), USNM 1116678, Isla Grande, southern shore facing La Guaira, between village and west point, coral rocks, in cryptic sponge, depth 1–1.5 m, coll. E. Tóth, 14 Feb 2007 [07-030, photo voucher]. Paratypes: 1 colony member, USNM 1116679, same collection data as for holotype [07-031, photo voucher]; 1 colony member, USNM 1116680, same collection data as for holotype [07-032, photo voucher]; 1 breeding female (queen), USNM 1116681, same collection data as for holotype [07-033, photo voucher]; 7 colony members, UP, Isla Grande, west point, coral rocks, probably in cryptic sponge, depth 1–2 m, coll. A. Anker and C. Hurt, 6 Oct 2005 [05-053]; 1 breeding female (queen), 13 colony members, USNM 1116682, Isla Grande, between village and west point, coral rubble conglomerate, in cryptic sponge, depth 1.5 m, coll. A. Anker, 22 Apr 2006 [06-412, photo voucher, 1 specimen dissected].

Diagnosis. Rostrum somewhat lower than orbital hoods, rather narrow at base, usually slender, distinctly longer than orbital teeth, with acute tip; orbital teeth triangular, broad at base, acute; both rostrum and orbital teeth slightly up-turned distally; notches between orbital teeth and rostrum usually moderately deep, rather Ushaped. Antennular peduncles with second segment slightly longer than wide; stylocerite length variable from falling short of distal margin to slightly overreaching distal margin of first segment. Antenna with basicerite having blunt to subacute, slightly projecting distodorsal tooth; scaphocerite with narrow blade, latter overreaching mid-length of scaphocerite and distolateral tooth of basicerite. Third maxilliped with crown of usually six spine-like setae on tip of ultimate segment. Major chela with palm approximately 2.5 times as long as fingers; distodorsal tooth on palm swollen, with slightly descendant acute point. Second pereiopod carpus with five segments, first carpal segment about three times length of second. Third pereiopod with propodus bearing five spine-like setae (not including distal pair); dactylus moderately stout. Uropodal exopod with three fixed teeth (including lateral tooth of diaeresis) and slender movable spine-like seta. Telson with longitudinal median depression and two pairs of non-particularly stout spine-like setae inserted anterior and posterior to mid-length, respectively; posterior margin broad, about half-length of anterior width (see Figs. 4 , 5 ). For detailed description of general features of S. paraneptunus species complex see Dardeau (1984) and Ríos & Duffy (2007).

Etymology. This new eusocial species is named after Dr. J. Emmett Duffy (Virginia Institute of Marine Science, VIMS), who discovered eusociality in Synalpheus ( Duffy 1996a) and subsequently published numerous studies on this subject and also on the taxonomy of the S. gambarelloides group ( Duffy 1996b, 2003).

Colour pattern. Whitish semitransparent, with red chromatophores on frontal region, antennules and third maxilliped; major chela whitish, distal margin of palm and fingers with olive-green tinge (except for pale area surrounded by darker margin on dactylus), tips amber-yellow; ovaries or fresh brood bright green ( Fig. 14 A, B).

Size. Largest non-breeding colony member, CL 2.7 mm; largest breeding female, CL, 3.5 (holotype, CL 3.25 mm).

Type locality. Isla Grande, Colón Province, Panama.

Distribution. With certainty known only from the Caribbean coast of Panama: Isla Grande, the type locality, and the nearby La Guaira; its presence in the Florida Keys requires confirmation (see under Remarks).

Life history. At the type locality, S. duffyi n. sp. was extracted from cryptic sponges, Neopetrosia subtriangularis (Duchassaing, 1850) ( Fig. 15 A, B), and possibly Calyx podatypa (de Laubenfels, 1934), either growing on the underside of flat dead coral slabs or amongst coral rubble. Where S. duffyi n. sp. occurs the sponge has a more massive shape, whereas when associated with other pair-living species of Synalpheus it usually forms a wide tube. A single sponge seems to be inhabited by a single colony, up to 80 non-breeding individuals (E. Tóth, pers. obs.), and only one reproductive female (queen). Occasionally, a colony of S. duffyi n. sp. shares the host sponge with a pair of S. goodei Coutière, 1909 , S. pandionis Coutière, 1909 or S. brevidactylus n. sp. (see below).

Remarks. Synalpheus duffyi n. sp. shares with S. paraneptunus the scaphocerite having a relatively well developed blade ( Fig. 4 A); the presence of three teeth on the uropodal exopod ( Fig. 4 G); and the stylocerite barely reaching the distal margin of the first segment of the antennular peduncle, going slightly beyond it in some specimens ( Fig. 4 H). However, the new species differs from S. paraneptunus by the shorter first segment in the carpus of the second pereiopod ( Fig. 4 D); the broader, more U- than V-shaped notches between the rostrum and the orbital teeth ( Fig. 4 A, J–L); and less stout and more anteriorly inserted dorsal spine-like seta on the telson ( Fig. 4 G).

We tentatively assign specimens Duffy (2003) called “ Synalpheus paraneptunus small” from Florida Keys to S. duffyi n. sp., based on the second author’s (ET) brief earlier observations and on the fact that Duffy’s species is small and eusocial, just like S. duffyi n. sp. However, a morphological and eventually genetic comparison between S. duffyi n. sp. and “ S. paraneptunus small” is needed to verify whether or not they belong to the same species. It is also important to note that S. paraneptunus in Duffy (2003) and Morrison et al. (2004) is actually not S. paraneptunus sensu Coutière (1909) ; the specific identity (or identities) of these specimens remains to be determined.

Figures

FIGURE 4. Synalpheus duffyi n. sp., paratype, non-breeding specimen (colony member) from Isla Grande, Panama (USNM 1116682) [A – G]; paratype, breeding female (queen) (USNM 1116682) [H, I]; three other paratypes, all nonbreeding specimens (USNM 1116682) [J – L]: A, frontal region, dorsal view; B, same, lateral view; C, third maxilliped, lateral view; D, second pereiopod, lateral view; E, third pereiopod, lateral view; F, abdomen of non-breeding specimen, lateral view; G, telson and uropods, dorsal view; H, aberrant frontal region, dorsal view; I, abdomen of breeding female (queen), lateral view; J, K, L, frontal margin of carapace (with basal antennular segments in J and K), dorsal view. Scale bar: 0.5 mm (A – E, G, H, J – L), 1 mm (F, I).

FIGURE 5. Synalpheus duffyi n. sp., paratype, non-breeding specimen (colony member) from Isla Grande, Panama (USNM 1116682) [A – F]; paratype, breeding female (queen) (USNM 1116682) [G]: A, major cheliped of non-breeding specimen, lateral view; B, same, mesial view; C, major chela, distal portion with opened fingers, lateral view; D, minor cheliped, mesial view; E, minor chela with opened fingers, lateral view, F, same, dorsolateral aspect; G, major cheliped of breeding female (queen), lateral view. Scale bar: 0.5 mm (C – F), 1 mm (A, B, G).

FIGURE 14. Life habitus and colour patterns. Synalpheus duffyi n. sp., Isla Grande, Panama [A, B]: A, larger queen and two smaller non-breeding colony members from the same colony, dorsal view; B, queen with embryos, lateral view. Synalpheus brevidactylus n. sp., Isla Grande, Panama [C, D]: C, breeding female and male (mated pair), dorsal view; D, breeding female, lateral view. Synalpheus bocas n. sp., Bocas del Toro, Panama [E – H]: E, male, dorsal view; F, breeding female; G, H, another breeding female, lateral and dorsal views on different backgrounds. Synalpheus belizensis n. sp., Carrie Bow Cay, Belize [I]: I, breeding female, dorsal view. Scale bars: ~ 2 mm.

FIGURE 15. Sponge hosts of some species from the Synalpheus paraneptunus Coutière, 1909 species complex: A, several members of a colony of Synalpheus duffyi n. sp. in their host sponge, possibly Neopetrosia subtriangularis, Isla Grande, Panama; B, same, close-up of a non-breeding colony member; C, Xestospongia rosariensis, main host of Synalpheus bocas n. sp., Bocas del Toro, Panama; D, same, longitudinal section showing details of canals; E, Xestospongia sp., occasional host of S. bocas n. sp., Bocas del Toro, Panama. Scale bars: ~ 3 mm (A, B), ~ 5 cm (C – E).