Salmoneus carvachoi, Anker, Arthur, 2007

Anker, Arthur, 2007, New species and records of alpheid shrimps, genera Salmoneus Holthuis and Parabetaeus Coutière, from the tropical western Atlantic (Decapoda, Caridea), Zootaxa 1653, pp. 21-39 : 27-29

Salmoneus carvachoi n. sp.

Fig. 3

Salmoneus ortmanni (not Rankin, 1898) – Carvacho, 1979: 453; Christoffersen, 1980: 137; Christoffersen, 1982: 94; Christoffersen, 1998: 362 (part.); Coelho dos Santos & Coelho, 2001: 78. [?] Salmoneus aff. ortmanni – Hernández Aguilera et al., 1996: 35.

[?] Salmoneus sp. – Coelho & Ramos, 1972: 151.

Material examined: Holotype: 1 non-ovig. specimen (male?), MNHN-Na 13680, Guadeloupe, estuary of Rivière Lézarde, dredge (“chalutage”) between estuary and canal, time: 15.40, coll. Rojas-Hostache, 13 Jun 1977. Paratypes: 1 ovig. female, MNHN-Na 2699, Guadeloupe, M 42.1, coll. and det. (as Salmoneus ortmanni ) A. Carvacho, 27 Jan 1977; 1 non-ovigerous specimen (male?), MNHN-Na 2669, Guadeloupe, M 32.5, coll. and det. (as Salmoneus ortmanni ) A. Carvacho, 27 Jan 1977 [dissected].

Description: Carapace glabrous ( Fig. 3 b, c). Rostrum longer than broad, reaching half length of second segment of antennular peduncle, with acute tip ( Fig. 3 a); lateral margins slightly concave proximally; ventral margin unarmed ( Fig. 3 b); rostral carina slight, not reaching beyond eyes posteriorly ( Fig. 3 a). Orbital spines acute, slightly mesially directed ( Fig. 3 a). Pterygostomial margin feebly protruding anteriorly, rounded ( Fig. 1 a, c). Eyes covered in dorsal view, visible in lateral view ( Fig. 3 a, b). Antennule with stylocerite falling short of distal margin of second segment of antennular peduncle, with acute tip; second segment as long as wide ( Fig. 3 a). Antenna with basicerite bearing subacute distoventral spine ( Fig. 3 b); scaphocerite broadly ovate, distolateral spine small, acute ( Fig. 3 a, b). Third maxilliped with rounded lateral plate; tip of ultimate segment with short apical and subapical spiniform setae. Chelipeds strongly asymmetrical in shape, unequal in size ( Fig. 3 d–h). Major cheliped ( Fig. 3 d–g) with unarmed ischium; merus somewhat inflated distally, ventrally flattened ( Fig. 3 e); carpus elongated, ventrally flattened to slightly depressed, distally with blunt lobes ( Fig. 3 d); chela excavated ventrally, flattened mesially ( Fig. 3 d, c); fingers about half as long as palm, cutting edges serrated, with about 13–14 small rounded teeth ( Fig. 3 f, g). Minor cheliped ( Fig. 3 h) with ischium shorter than merus, both unarmed; carpus subequal to merus; chela small, simple, with fingers subequal to palm. Second pereiopod ( Fig. 3 i) with ischium bearing small spiniform seta; carpus with five segments, first segment longer than sum of four other segments ( Fig. 3 j). Third pereiopod ( Fig. 3 k) with ischium bearing two small ventrolateral spiniform seta; merus about six times as long as wide; carpus unarmed; propodus with three slender ventral spiniform setae, including distal seta; dactylus simple, conical, very slender, about 3/4 length of propodus Fifth abdominal somite with acute posteroventral angle ( Fig. 3 l). Sixth abdominal somite without articulated plate, with acute posteroventral projection ( Fig. 3 l); preanal plate rounded. Second pleopod with appendix masculina subequal to appendix interna, furnished with slender spines on apex and along outer margin. Uropod with sinuous diaeresis and slender distolateral spiniform seta ( Fig. 3 m). Telson more than twice as long as wide proximally ( Fig. 3 m), tapering posteriorly, with two pairs of dorsal spiniform setae, inserted at about mid-length and 3/4 telson length, respectively ( Fig. 3 m); posterior margin with very shallow median notch and two pairs of spiniform setae at posterolateral angles, mesial setae distinctly longer than lateral setae ( Fig. 3 n). Gill/exopod formula typical for genus (see under S. ortmanni ).

Colour: Unknown.

Size: Holotype: CL 4.1 mm, TL 13.1 mm; ovigerous female paratype: CL 4.9 mm, TL 14.6 mm, nonovigerous paratype: CL 4.3 mm, TL 13.4 mm.

Etymology: The new species is named after Professor Alberto Carvacho (associated with the Museo Nacional de Historia Natural, Santiago de Chile), who collected most of the type specimens and published several studies dealing with alpheid and other caridean shrimps, including an important taxonomic note on Salmoneus ( Carvacho, 1989) .

Ecology: This species is probably confined to estuaries of brackish mangrove rivers and is able to tolerate low salinities ( Carvacho, 1979; Christoffersen, 1982). In Mar de Cananéia and Baía do Trapandé (São Paulo), it was collected at depths of 0.3–1.2 m. The ovigerous specimen from Paraná was dredged from the mud bottom at 22 m ( Christoffersen, 1982).

Type locality: Guadeloupe, French Antilles.

Distribution: Western Atlantic: French Antilles: Guadeloupe ( Carvacho, 1979, as S. ortmanni ; present study); Brazil: São Paulo, Paraná, possibly also Pernambuco and Sergipe ( Coelho & Ramos, 1972, as Salmoneus sp.; Christoffersen, 1982, 1998, as S. ortmanni ). The species reported as “ S. aff. ortmanni ” from southwestern Gulf of Mexico, from Veracruz to Yucatan ( Hernández Aguilera et al., 1996) may also refer to S. carvachoi n. sp., as well as part of Chace’s (1972) material from the Caribbean.

Remarks: Salmoneus carvachoi n. sp. differs from S. ortmanni by the slightly concave lateral margins of the rostrum (vs. slightly convex in S. ortmanni , cf. Fig. 1 b, 3a); the more slender walking legs (P3-5), with the P3 merus being six times as long as wide (vs. four in S. ortmanni ), and with a much more elongate dactylus (cf. Fig. 1 g, 3k); the P3 ischium armed with two spiniform setae (vs. one seta in S. ortmanni , cf. Fig. 1 g, 3k); the presence of a small spiniform seta on the P2 ischium (absent in S. ortmanni , cf. Fig. 1 f, 3i); the longer telson, bearing a less pronounced median notch on the posterior margin (cf. Fig. 1 j, 3n); the more slender merus and chela of the major cheliped (cf. Fig. 2 a–d, 3d–f); and the slightly higher number of teeth on the fingers of the major chela (13–14 in S. carvachoi , n. sp. vs. 10–12 in S. ortmanni , cf. Fig. 2 e, 3f). The Brazilian specimens of S. carvachoi n. sp. ( Christoffersen, 1982, as S. ortmanni ) are morphologically similar to those from the Caribbean.

Figures

FIGURE 1. Salmoneus ortmanni Rankin, 1898, ovigerous specimen from Atol das Rocas, Brazil (MNRJ 20213): acephalothorax and major cheliped, lateral view; b—frontal region, dorsal view; c—same, lateral view; d—third maxilliped, lateral view; e—same, tip of ultimate segment; f—second pereiopod, lateral view; g—third pereiopod, lateral view; h—second pleopod with eggs, mesial view; i—preanal plate of sixth abdominal somite, ventral view; j—telson and right uropod, dorsal view. Scale bars = 1 mm.

FIGURE 2. Salmoneus ortmanni Rankin, 1898: ovigerous specimen from Atol das Rocas, Brazil (MNRJ 20213): amajor cheliped, mesial view; b—same, coxa to carpus, lateral view; c—same, chela, ventrolateral view; d—same, dorsolateral view; e—same, chela with opened fingers, lateral view; f—minor cheliped, lateral view; g—same, carpus and chela, mesial view. Scale bar = 1 mm.

FIGURE 3. Salmoneus carvachoi n. sp.: paratype, non-ovigerous specimen (male?) from Guadeloupe, French Antilles (MNHN-Na 2669): a—frontal region, dorsal view; b—same, lateral view; c—carapace, lateral view; d—major cheliped, ventromesial view; e—same, lateral view; f—same, chela with opened fingers, mesial view; g—same, chela fingers (opened), lateral view; h—minor cheliped, lateral view; i—second pereiopod, lateral view; j—same, carpus and chela; k—third pereiopod, lateral view; l—posterior abdominal somites and tail fan, lateral view; m—telson and right uropod, dorsal view; n—telson, posterior half, dorsal view. Scale bars = 1 mm.