Salmoneus ortmanni ( Rankin, 1898 )

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: 23-26

publication ID

10.5281/zenodo.179791

publication LSID

lsid:zoobank.org:pub:C405C7B8-11C1-424F-944C-7C59BD03BCAC

persistent identifier

http://treatment.plazi.org/id/7F0587F6-FFFF-8028-D686-75FDC9902CD8

treatment provided by

Plazi

scientific name

Salmoneus ortmanni ( Rankin, 1898 )
status

 

Salmoneus ortmanni ( Rankin, 1898) 

Fig. 1View FIGURE 1, 2View FIGURE 2

Athanas ortmanni Rankin, 1898: 251  ; Verrill, 1900: 579.

Jousseaumea ortmanni  – Coutière, 1900: 356; Verrill, 1922: 122; Schmitt, 1936: 367.

Salmoneus ortmanni  – Chace, 1972: 79 (part.?); Banner & Banner, 1981: 56; Martínez-Iglesias et al., 1996: 35; Christoffersen, 1998: 362 (part.).

Not Salmoneus ortmanni  – Carvacho, 1979: 453; Christoffersen, 1980: 137; Christoffersen, 1982: 94; Christoffersen, 1998: 362 (part.); Coelho dos Santos & Coelho, 2001: 78 (= S. carvachoi  n. sp., see below).

(?) Not Salmoneus ortmanni  – Carvacho & Ríos, 1983: 283; Ríos & Carvacho, 1983: 462; Christoffersen & Ramos, 1988: 63; Villalobos Hiriart et al., 1989: 16; Ríos, 1989: 154; Ríos, 1992: 7; Wicksten & Hendrickx, 1992: 6; Wicksten, 1993: 151; Villalobos, 2000: 74; Wicksten & Hendrickx, 2003: 66 (= Salmoneus  sp. aff ortmanni  ; see below).

Salmoneus evermanni  (lap. cal.) – Holthuis, 1990: 111.

Salmoneus  sp. – Rodríguez, 1986: 180.

Material examined: 2 ovig. females, MNRJAbout MNRJ 20213, Brazil, Atol das Rocas  (AR), LT 800, Ilha do Cemitério, intertidal, coll. C. Serejo and M.C. Rayol, 20 Oct 2001 [1 specimen dissected]; 1 ovig. female, MNRJAbout MNRJ 20214, LT 795, Brazil, Atol das Rocas  , between Ilha do Farol and Ilha do Cemitério, low tide, coll. C. Serejo and M.C. Rayol, 31 Oct 2001; 2 ovig. females, MNRJAbout MNRJ 20215, Brazil, Atol das Rocas  , between Ilha do Farol and Ilha do Cemitério, low tide, coll. C. Serejo and M.C. Rayol, 25 Oct 2001; 1 non-ovigerous specimen (male?), MNHN-Na 15686, Aruba, Pos Chiquito, from coral rocks, depth 0.5–1 m, coll. A. Anker, 7–8 Dec 2003; 1 ovig. female, MNHN-Na 15685, Aruba, Baby Beach, from coral rubble and porous rocks, depth 1–1.5 m, coll. A. Anker, 6 Dec 2003.

Description: Carapace slightly setose ( Fig. 1View FIGURE 1 a, c). Rostrum as long as broad, reaching half length of second segment of antennular peduncle, with acute tip ( Fig. 1View FIGURE 1 b); lateral margins slightly convex proximally; ventral margin unarmed ( Fig. 1View FIGURE 1 c); rostral carina distinct, reaching beyond eyes posteriorly ( Fig. 1View FIGURE 1 b). Orbital spines acute, slightly mesially directed ( Fig. 1View FIGURE 1 b). Pterygostomial margin protruding anteriorly, rounded ( Fig. 1View FIGURE 1 a, c). Eyes covered in dorsal and lateral view ( Fig. 1View FIGURE 1 a, b). Antennule with stylocerite reaching or slightly overreaching distal margin of second segment of antennular peduncle, with acute tip; second segment as long as wide ( Fig. 1View FIGURE 1 b). Antenna with basicerite bearing acute distoventral spine ( Fig. 1View FIGURE 1 c); scaphocerite broadly ovate, distolateral spine small, acute ( Fig. 1View FIGURE 1 b). Third maxilliped with rounded lateral plate; tip of ultimate segment with short apical and subapical spiniform setae ( Fig. 1View FIGURE 1 d, e). Chelipeds strongly asymmetrical in shape, unequal in size ( Fig. 2View FIGURE 2). Major cheliped ( Fig. 2View FIGURE 2 a–e) with unarmed ischium; merus inflated distally, ventrally flattened; carpus elongated, ventrally flattened to slightly depressed, distally lobed ( Fig. 2View FIGURE 2 c); chela excavated ventrally, flattened mesially ( Fig. 2View FIGURE 2 a, c); fingers about half as long as palm, cutting edges serrated, with about 10–12 rounded teeth ( Fig. 2View FIGURE 2 e). Minor cheliped ( Fig. 2View FIGURE 2 f, g) with ischium subequal to merus, both unarmed; carpus slightly shorter than merus; chela small, simple, with fingers subequal to palm. Second pereiopod ( Fig. 1View FIGURE 1 f) with unarmed ischium; carpus bearing five segments, first segment longer than sum of four other segments. Third pereiopod ( Fig. 1View FIGURE 1 g) with ischium bearing one ventrolateral spiniform seta; merus about four times as long as wide; carpus unarmed except for one slender distoventral spiniform seta; propodus with four slender ventral spiniform setae, including distal spiniform seta; dactylus simple, conical, moderately slender, less than half length of propodus. Fifth abdominal somite with subacute posteroventral angle. Sixth abdominal somite without articulated plate, with subacute posteroventral projection; preanal plate rounded ( Fig. 1View FIGURE 1 i). Second pleopod with appendix masculina subequal to appendix interna, furnished with slender setae on apex and along outer margin ( Fig. 1View FIGURE 1 h). Uropod with sinuous diaeresis and slender distolateral spinform seta ( Fig. 1View FIGURE 1 j). Telson about twice as long as wide proximally, tapering posteriorly, with two pairs of dorsal spiniform setae, inserted at about mid-length and 3 / 4 telson length, respectively ( Fig. 1View FIGURE 1 j); posterior margin with rounded median notch and two pairs of spiniform setae at posterolateral angles, mesial setae distinctly longer than lateral setae ( Fig. 1View FIGURE 1 j). Gill/exopod formula typical for genus: 5 pleurobranchs (above P 1-5); 1 arthrobranch (above Mxp 3); 0 podobranch; 2 lobe-shaped epipods (Mxp 1-2); 5 mastigobranchs or strap-like epipods (Mxp 3, P 1-4); 5 sets of setobranchs (P 1-5); 3 exopods (Mxp 1-3).

Colour: The specimens from Aruba were uniformly yellow-orange.

Size: The largest AR specimen has CL 4.5 mm, TL 13.5 mm.

Ecology: The Aruba specimens were found in crevices of coral rubble and rocks in a depth of 1–1.5 m; the AR specimens were collected intertidally, probably under rocks. In the Caribbean, S. ortmanni  occurs under rocks from the tide pool level down to about 3–4 m, and on turtle grass flats, under rocks and rubble ( Chace, 1972; pers. obs.), occasionally also in tide pools near low tide level ( Chace, 1972) and inside empty Strombus  shells and among mangrove roots ( Rodríguez, 1986).

Type locality: Nassau, New Providence, Bahamas.

Distribution: Western Atlantic: Caribbean Sea: Bahamas, Cuba, W Mexico (?), Lesser Antilles, Aruba, Venezuela; Bermuda ( Rankin, 1898; Verrill, 1922; Chace, 1972; Christoffersen, 1982, 1998; Rodríguez, 1986; Martínez-Iglesias et al., 1996; present study), Brazil: Atol das Rocas  (present study). Christoffersen’s (1982) record of S. ortmanni  from southern Brazil most likely refers to S. carvachoi  , n. sp. (see below). The records of S. ortmanni  from the eastern Pacific (Ríos & Carvacho, 1983; Villalobos Hiriart et al., 1989; Ríos, 1989, 1992; Wicksten, 1993; Villalobos, 2000) most probably refer to closely related, undescribed species (see below).

Remarks: Salmoneus ortmanni  belongs to the S. ortmanni  species group (see Anker & Marin, 2006 for definition of species groups). Members of this group are unique in having a major cheliped with inflated and ventrally excavated merus and carpus. Until now, all western Atlantic and eastern Pacific specimens with this features were assigned to S. ortmanni  (e.g., Carvacho, 1979; Christoffersen, 1998; Wicksten & Hendrickx, 2003). However, variation in the proportions of the major chela and especially in the shape of the dactylus of the third to fifth pereiopods suggests that S. ortmanni  is a species complex, with two distinct forms in the western Atlantic (and perhaps one or two distinct forms in the eastern Pacific, see below).

In Christoffersen’s specimens from southern Brazil (São Paulo and Paraná), the major chela is 2.5–3 times longer than wide, compared to only twice as long as wide in the type ( Rankin, 1898: 251). In the AR specimens, the major chela appears to be stouter compared to that of the specimen from São Paulo illustrated by Christoffersen (1982), and approaching the ratio of the chela in the original figure by Rankin (1898). Furthermore, the dactylus of the third pereiopod of the AR specimens is moderately slender, only about half as long as the propodus, and so very similar to the proportions of the dactylus in Rankin’s figure, as well as in the Caribbean material reported by Chace (1972). In contrast to this, Christoffersen’s (1982) specimens had a very slender dactylus, with a ratio dactylus/propodus equal to 5 / 7. A similar ratio is also found in specimens from Guadeloupe reported by Carvacho (1979) (see below). Also, the merus and propodus of the third pereiopod are significantly broader in the AR specimens compared to the specimen from São Paulo (cf. Fig. 1View FIGURE 1 g and Christoffersen, 1982: 99, fig. 2 f).

Christoffersen (1982) also reported variation in the shape of the rostrum and length of the scaphocerite. In the AR specimens, the rostrum is indeed slightly broader than in Christoffersen’s specimen from São Paulo (cf. Fig. 1View FIGURE 1 b and Christoffersen, 1982: 98, fig. 1 a). Furthermore, in the AR specimens, the telson is broader and has a more pronounced median notch on the posterior margin (cf. Fig. 1View FIGURE 1 j and Christoffersen, 1982: 98, fig. 1 d). Notably, both Christoffersen’s and Carvacho’s specimens with the elongate P 3-5 dactyli were found on mud bottoms in mangrove-estuarine conditions, while the AR and Aruba specimens with a stouter P 3-5 dactyli were collected on mixed sand-rubble bottoms. This ecological difference seem to corroborate the differences in morphology, suggesting that two species are currently confused under S. ortmanni  : a coral rubbleseagrass species, with stouter P 3-5 dactyli – S. ortmanni sensu  stricto (sensu Rankin, 1898), and a mangroveestuarine species with longer and more slender P 3-5 dactyli – S. ortmanni sensu Carvacho (1979)  and Christoffersen (1982). The latter species is described below as new.

The specimens from Los Roques, Venezuela, reported as “ Salmoneus  sp.” by Rodríguez (1986) agree almost perfectly with the AR specimens, including the shape of the rostrum and the broad telson bearing a shallow rounded median notch.

The records of S. ortmanni  from the Gulf of California and Galapagos (e.g., Ríos & Carvacho, 1983; Ríos, 1989, 1992; Wicksten, 1993; Villalobos, 2000) should be regarded as questionable. Ríos (1989, 1992) examined and compared specimens from the Gulf of California (Bahía Concepición and Rio Mulegé), Laguna Percebú (Baja California), and Guadeloupe, French Antilles (Carvacho’s specimens), and noted that the posterior margin of the telson sometimes has a “vestigial” median notch. However, this notch – an important taxonomic character of the Salmoneus  species - is quite deep in the AR specimens ( Fig. 1View FIGURE 1 j) and Los Roques specimens ( Rodríguez, 1986). Ríos (1992) noted that the ischium of the third and fourth pereiopods may bear either one or two spiniform setae. Ríos also found that the specimens from the Gulf of California differ from the specimens from Guadeloupe (described below as S. carvachoi  n. sp.) by the absence of the ischial spiniform seta on the second pereiopod; this seta also lacks in the AR specimens ( Fig. 1View FIGURE 1 f). The present author examined several specimens of S. cf. ortmanni  collected by Rafael Robles (University of Louisiana, Lafayette, LA, USA) from the mudflats of the Rio Mulegé estuary, northern Gulf of California, and specimens identified as S. ortmanni  from Bahía Málaga, Pacific coast of Colombia ( USNMAbout USNM 244251). All these specimens appear not to represent S. ortmanni sensu Rankin, 1898  . The above-listed differences, if shown to be consistent, could prove to be important characters in the separation of the eastern Pacific form (or forms) from both S. ortmanni  and S. carvachoi  n. sp. However, the status of the eastern Pacific specimens of S. ortmanni  s. lat. will be subject of a separate study.

MNRJ

Museu Nacional/Universidade Federal de Rio de Janeiro

USNM

Smithsonian Institution, National Museum of Natural History

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Alpheidae

Genus

Salmoneus

Loc

Salmoneus ortmanni ( Rankin, 1898 )

Anker, Arthur 2007

2007
Loc

Salmoneus evermanni

Holthuis 1990: 111

1990
Loc

Salmoneus

Rodriguez 1986: 180

1986
Loc

Salmoneus ortmanni

Santos 2001: 78
Christoffersen 1998: 362
Christoffersen 1982: 94
Christoffersen 1980: 137
Carvacho 1979: 453

1979
Loc

Salmoneus ortmanni

Christoffersen 1998: 362
Martinez-Iglesias 1996: 35
Banner 1981: 56
Chace 1972: 79

1972
Loc

Athanas ortmanni

Verrill 1900: 579Rankin 1898: 251

1900
Loc

Jousseaumea ortmanni

Schmitt 1936: 367
Verrill 1922: 122
Coutiere 1900: 356

1900