Salmoneus paulayi, Anker, Arthur, 2011

Anker, Arthur, 2011, Three new species of the alpheid shrimp genus Salmoneus Holthuis, 1955 (Crustacea, Decapoda) from the tropical western Pacific, Zootaxa 2839, pp. 67-84 : 68-73

publication ID	https://doi.org/ 10.5281/zenodo.208086
DOI	https://doi.org/10.5281/zenodo.6194229
persistent identifier	https://treatment.plazi.org/id/03E41126-FF92-0A44-EE88-1A8EFDD7FC87
treatment provided by	Plazi
scientific name	Salmoneus paulayi
status	sp. nov.

Treatment

Salmoneus paulayi View in CoL n. sp.

( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Type material. Mariana Islands, Guam. Holotype: ovigerous specimen (CL 6.1 mm), FLMNH UF Arthropoda 28067, west coast of Guam, north of Apra Harbor, between Piti Channel and Cabras, reef flat, under large pieces of dead coral, night snorkeling, depth 0.5–1.5 m, snorkeling, coll. A. Anker, 19 June 2010 [fcn GUOK-0700]. Paratypes: 1 ovigerous specimen (CL 5.9 mm), FLMNH UF Arthropoda 28066, east coast of Guam, north of Talofofo, off public beach, reef flat with fossilised coral platform, under large coral rocks, depth 0.5–1 m, snorkeling, coll. A. Anker, 16 June 2010 [fcn GUOK-0466]; 1 ovigerous specimen (CL 4.8 mm), OUMNH.ZC. 2011-03-171, east coast of Guam, Mangilao, about 100 m southwest of University of Guam Marine Laboratory, shallow reef flat with abundant coral debris and loose rubble, abundant algal cover, under large coral rocks, depth 0.5–1 m, snorkeling, coll. A. Anker, 18 June 2010 [fcn GUOK-0677].

Description. Relatively large-sized species of Salmoneus (CL 4.8–6.1 mm). Carapace somewhat domed, finely pitted, especially dorsally, and densely covered with short stubby setae; anterolateral region with distinct suture ( Fig. 1 View FIGURE 1 A, B); cardiac notch deep. Rostrum relatively short, only slightly over-reaching distal margin of first article of antennular peduncle, broad, subtriangular, wider than long at base, slightly descendant in lateral view, without distinct medio-dorsal carina; lateral margins slightly concave; tip acute, slightly curved upwards in lateral view; ventral margin unarmed ( Fig. 1 View FIGURE 1 A–C). Orbital teeth small compared to rostrum, subtriangular, subacute distally, directed anteromesially ( Fig. 1 View FIGURE 1 A, B). Pterygostomial angle broadly rounded, not protruding ( Fig. 1 View FIGURE 1 B).

Pleura of first four abdominal somites rounded posteroventrally; fifth pleuron with subacute but non-projecting posteroventral angle; sixth somite without distinct articulated plate, with faint suture only; preanal plate rounded. Telson relatively broad, widest in proximal third, distally tapering; dorsal surface with two pairs of stout spiniform setae inserted at some distance from lateral margin, at about 0.5 and 0.75 telson length, respectively; posterior margin approximately half as long as anterior margin, with shallow median incision and two pairs of long spiniform setae, mesial narrower and longer than lateral; margin between mesial spiniform setae furnished with two pairs of plumose setae ( Fig. 1 View FIGURE 1 D).

Eyes concealed in dorsal view, only anterior-most portion visible in lateral view; cornea slightly reduced ( Fig. 1 View FIGURE 1 A, B). Epistomial sclerites with conspicuous subacute processes.

Antennular peduncles very stout, with second article slightly wider than long; stylocerite with subacute tip falling short of distal margin of second article; ventromesial carina with small, anteriorly directed tooth; lateral flagellum biramous, fused portion short, with two or three very short articles; accessory ramus long, with at least seven tufts of aesthetascs ( Fig. 1 View FIGURE 1 A, B, E). Antenna with basicerite ending in stout tooth distoventrally; scaphocerite more rounded than ovate, with broad, anteriorly rounded blade reaching well beyond small acute distolateral tooth, latter not reaching beyond end of antennular peduncle; carpocerite very short, barely reaching half-length of scaphocerite ( Fig. 1 View FIGURE 1 A, B, F).

Mouthparts typical for genus. Third maxilliped slender; coxa with ovate lateral plate above mastigobranch; penultimate article about 2.5 times as long as wide, slightly widening distally, with five transverse rows of dense serrulate setae on mesial side; ultimate article furnished with transverse rows of thick serrulate setae mesially, tapering distally, apex with four short spiniform setae; arthrobranch well developed ( Fig. 1 View FIGURE 1 G–J).

Chelipeds unequal in size, asymmetrical in shape, minor cheliped about 0.6 length of major cheliped, more slender, with comparatively much smaller and shorter chela ( Figs. 2 View FIGURE 2 A, G, 4); both chelipeds folded under cephalothorax when not in use. Major cheliped elongate, moderately robust; ischium distally widening, with small spiniform seta on ventrolateral surface; merus about four times as long as wide, smooth, depressed distoventrally; carpus elongate, about 0.5 length of merus, distally widening, ventrally depressed ( Fig. 2 View FIGURE 2 A, B); chela somewhat compressed, smooth, ventral margin strongly concave at pollex base; fingers longer than palm, with tips strongly curved and crossing; cutting edge of dactylus with four or five widely spaced, strong, subacute teeth and broadly rounded, longitudinally finely striated, lamellar convexities intercalated between these teeth; one much smaller tooth present adjacent to most-distal tooth; cutting edge of pollex with lamellar convexities similar to those on the dactylus, two strong teeth arising between these convexities in most-proximal portion of pollex ( Fig. 2 View FIGURE 2 C–F). Minor cheliped less robust than major cheliped, with chela less swollen and with much shorter fingers; ischium with small spiniform seta on ventrolateral surface; merus about four times as long as wide, smooth, depressed ventrally; carpus cup-shaped, distally widening, ventrally slightly depressed ( Fig. 2 View FIGURE 2 G, H); chela smooth, simple, with fingers stout, about 0.6 length of palm; cutting edges serrated with about five subtriangular interdigitating teeth; tips moderately curved, not strongly crossing ( Fig. 2 View FIGURE 2 I).

Second pereiopod slender; ischium without spiniform setae; merus about the same length as ischium; carpus five-articulated, ratio of carpal articles (from proximal to distal) approximately equal to: 4: 1: 0.8: 1: 1.5; chela simple, slightly longer than most-distal carpal article ( Fig. 3 View FIGURE 3 A). Third pereiopod moderately slender, compressed; ischium without spiniform setae on ventrolateral surface; merus about five times as long as wide, unarmed; carpus much more slender than merus, about 0.8 merus length, with slender seta distoventrally; propodus with four spiniform setae along ventral margin and one pair of stouter and longer distal spiniform setae adjacent to dactylus; dorsal margin of propodus with two small spiniform setae; dactylus about 0.3 propodus length, simple, moderately slender, gradually curving distally, with some setae at about 0.7 dactylar length ( Fig. 3 View FIGURE 3 B–D). Fourth pereiopod very similar to third pereiopod. Fifth pereiopod somewhat longer and more slender than third pereiopod; ischium unarmed; merus shorter than carpus; propodus with three small spiniform setae along ventral margin and a dozen rows of thick serrulate setae distolaterally ( Fig. 3 View FIGURE 3 E, F).

Male second pleopod with appendix masculina not exceeding appendix interna, apex and mesial margin with numerous stiff setae ( Fig. 1 View FIGURE 1 K). Uropod with lateral lobe of protopod bearing sharp tooth; endopod and exopod broadly ovoid; diaeresis sinuous, with inconspicuous blunt distolateral tooth adjacent to slender spiniform seta ( Fig. 1 View FIGURE 1 L). Gill-exopod formula typical for genus (see Anker & Marin 2006).

Colour in life: semitransparent, hyaline-whitish, with bright yolk-yellow gonads or freshly-laid eggs ( Fig. 4 View FIGURE 4 ).

Variation. The three type specimens present a rather minor morphological variation, for instance, in the length and slenderness of the rostrum, the proportions of the major and minor chelipeds, and the presence of four or five teeth on the dactylus of the major chelae (cf. Fig. 4 View FIGURE 4 C, D).

Etymology. Named after Dr. Gustav Paulay (FLMNH) for his continuous support of the author’s fieldwork and taxonomic studies on the Alpheidae and other Decapoda .

Ecology. Shallow back reef flats, sand and loose rubble with large coral debris, depth range 0.5–1 m; under large dead corals deeply immerged in sand and loose rubble.

Type locality. Guam, Mariana Islands, northwestern Pacific Ocean.

Distribution. Presently known only from Guam (Mangilao, Talofofo and Apra Habror area).

Remarks. Based on the presently available morphological evidence, S. paulayi n. sp. can be placed in the S. jarli ( Holthuis, 1951) species group as defined by Anker & Marin (2006), together with S. jarli ( Holthuis, 1951) , S. caboverdensis Dworschak, Anker & Abed-Navandi, 2000 , S. erasimorum Dworschak, Anker & Abed-Navandi, 2000 , S. brucei Komai, 2009 , S. degravei Anker, 2010 , and possibly S. seticheles Anker, 2003 (see Dworschak et al. 2000; Anker 2003b; Anker & Marin 2006; Komai 2009; Anker 2010). The main character defining this group is the elongation and stoutness of the minor cheliped, accompanied by the enlargement of the minor chela. In all other species of Salmoneus the minor cheliped is significantly smaller than the major cheliped, not elongate (not much longer than the second pereiopod), slender, and with a small, non-inflated chela ( Anker & Marin 2006). However, the monophyly of the S. jarli group in its present composition needs to be tested with combined analyses of morphological and molecular characters (see also Anker 2010).

Salmoneus paulayi View in CoL n. sp. can be easily distinguished from all species of the S. jarli View in CoL group and most previously described species of Salmoneus View in CoL by the unique configuration on the finger cutting edges of the major chela, consisting of thin, broadly rounded and finely striated tooth plates, intercalated between strong subtriangular teeth, the latter being present along the entire cutting edge on the dactylus, but only proximally on the pollex ( Fig. 2 View FIGURE 2 E, F). Salmoneus tafaongae Banner & Banner, 1966 View in CoL is the only species of Salmoneus View in CoL described on the basis of a mutilated specimen missing the major cheliped and without illustrations ( Banner & Banner 1966); however, the extremely long and slender rostrum, one of the main characteristics of S. tafaongae View in CoL , as well as the non-enlarged minor cheliped immediately separate this species from S. paulayi View in CoL n. sp.