Salmoneus gimlii, Ashrafi & Ďuriš, 2025

Salmoneus gimlii sp. nov.

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

Salmoneus aff. erasimorum View in CoL — Ashrafi et al., 2025: 8, fig. 3B.

Type material. Holotype: ovig. specimen (cl 3.1 mm), MNHN-IU-2014-827, Kavieng 2014 exped., stn KZ15; Kavieng Region, NW New Ireland, Bismarck Sea, Papua New Guinea, 02°37,1’S, 150°46,4’E, 20 Jun. 2014; depth 6.6 m, under stone on sandy bottom; leg. Z. Ďuriš. GoogleMaps

Description. Carapace ( Fig. 1A–C View FIGURE 1 ) dorsally and dorsolaterally covered by setae, without carina or tubercle; frontal region entirely concealing eyes in dorsal view and almost fully concealing eyes in lateral view; rostrum short, broadly triangular in dorsal view, remarkably broader than long, with subacute tip overreaching midlength of first antennular article; without rostral carina; orbital teeth very small, subacute, as long as wide; anterolateral suture present, pterygostomial angle broadly rounded, cardiac notch deep.

Pleon ( Fig. 1C View FIGURE 1 ) covered with setae dorsally and dorsolaterally; pleura of first to fourth pleonites rounded anteroventrally and posteroventrally; fifth pleuron subangular posteroventrally; sixth pleuron with subtriangular projection flanking each side of telson, posteroventral suture incomplete.

Telson ( Fig. 1D View FIGURE 1 ) subrectangular, tapering distally, about 4.5 times as long as distal width, covered by short setae; dorsal surface with two pairs of spiniform setae located at about 0.5 and 0.8 telson length, respectively; posterior margin with very shallow central notch furnished with 4 setae, and two pairs of spiniform setae, lateral ones about 1.3 times as long as mesial ones and about 4 times as long as spiniform setae on dorsal surface.

Antennule ( Fig. 1B, C View FIGURE 1 ) with peduncle relatively stout; first article approximately as long as broad; stylocerite relatively robust, with more or less subacute tip, reaching to distal margin of second article; second article slightly longer than broad, dorsally covered by setae; third article subequal to second article, dorsally covered by setae; lateral antennular flagellum biramous, fused portion with two subdivisions, shorter ramus well developed, reaching to about eighth subdivision of longer ramus, with five groups of aesthetascs.

Antenna ( Fig. 1B, C View FIGURE 1 ) with stout basicerite, its distoventral margin armed with elongate subacute tooth, superior margin with small blunt projection; scaphocerite stout, ovoid, reaching to about midlength of third article of antennular peduncle, lateral margin convex, distolateral tooth falling short of distal margin of blade; carpocerite reaching midlength of second article of antennular peduncle and overreaching midlength of scaphocerite; flagellum not particularly stout.

Third maxilliped ( Fig. 3A View FIGURE 3 ) with coxa bearing strap-like epipod and broadly rounded lateral plate; antepenultimate article slender, fused to ischium and basis without visible sutures, about eight times as long as proximal depth; penultimate article relatively short, about 0.3 times as long as antepenultimate article; ultimate article about 2.5 times as long as penultimate article, distally armed with two small subapical spiniform setae; exopod slender, falling short of distal margin of antepenultimate article; arthrobranch normally developed, multilamellate.

First pereiopods ( Fig. 2 View FIGURE 2 ) asymmetrical in shape, subequal in size. Major cheliped ( Fig. 2A–C View FIGURE 2 ) relatively robust, carried flexed under body when not in use; coxa with strap-like epipod and setobranch; ischium slender, five times as long as proximal width, armed with one spiniform seta on ventrolateral margin; merus about 1.3 times as long as ischium, slender in proximal sixth but abruptly widening afterwards, with midlength widest and about four times as wide as proximal sixth, ventral surface longitudinally concave; carpus short, cup-shaped distally; chela enlarged, as long as basis to merus lengths combined; palm moderately swollen, about twice as long as wide in dorsal view, with deep complex groove proximally; fingers slender, about 1.2 times as long as palm, twisted with strongly crossing fingertips, not gaping when closed; pollex with cutting edge armed with 12 small teeth distributed evenly on proximal half and one tooth on distal fourth; dactylus with 9 small teeth on proximal third of cutting edge obscuring distally and two teeth located on 0.7 and 0.9 of its length. Subminor cheliped ( Fig. 2D, E View FIGURE 2 ) slightly shorter than major cheliped; coxa with strap-like epipod and setobranch; ischium slender, about five times as long as broad, armed with one spiniform seta on ventral margin; merus slender in proximal third and abruptly widening more distally to widest midpoint about three times as wide as proximal sixth, distal half slightly concave accommodating carpus when flexed, slightly longer than ischium; carpus short, cup-shaped, widening distally; chela enlarged, stout, as long as ischium and merus combined lengths; palm swollen, about twice as long as wide; fingers about 0.5 times as long as palm, with strongly crossing fingertips, not gaping when closed; pollex with cutting edge sinuous, armed with three strong teeth on convex proximal half and about six small teeth on convex distal half; dactylus with two stout teeth on proximal half of cutting edge, with distal tooth stronger, distal half smooth.

Second pereiopod ( Fig. 3B View FIGURE 3 ) slender; coxa with strap-like epipod and setobranch; ischium about six times as long as wide, armed with one spiniform seta on ventrolateral margin; merus slender, slightly longer than ischium; carpus 1.2 times as long as merus, with five subdivisions, proximal one longest, slightly shorter than combined length of others; chela about 0.3 times as long as carpus, palm and fingers subequal in length.

Third pereiopod ( Fig. 3C View FIGURE 3 ) moderately slender; coxa with strap-like epipod and setobranch; ischium slightly widening distally, about 3.5 times as long as wide, with small spiniform seta on ventrolateral surface; merus slender, about 1.5 times as long as ischium; carpus slender, subequal to merus, seven times as long as wide, with slender spiniform seta on distoventral margin; propodus slightly shorter than carpus, ventral margin armed with three spiniform setae in addition to distal pair of spiniform setae flanking dactylar base; dactylus simple, moderately slender, slightly curved, about 0.4 times as long as propodus. Fourth pereiopod ( Fig. 3D View FIGURE 3 ) generally similar to third one, somewhat more slender; ischium unarmed ventrally. Fifth pereiopod ( Fig. 3E View FIGURE 3 ) similar to fourth pereiopod in length; coxa without strap-like epipod, with setobranch; merus twice as long as ischium; carpus lacking spiniform seta on distoventral margin; propodus about 1.2 times as long as carpus, bearing eight transverse rows of microserrulate setae on distal half of distoventral margin and four slender spiniform setae on ventral margin in addition to distal pair.

Uropods ( Fig. 1D View FIGURE 1 ) with lateral and mesial lobes of protopod elongated, both subacute distally; exopod ovate, distolateral margin with small triangular tooth adjacent to stout spiniform seta, diaeresis sinuous, with blunt lobe mesial to spiniform seta; endopod slightly longer than exopod, slender, ovoid, without specific features.

Colour in life ( Fig. 4 View FIGURE 4 ). Body completely semi-transparent, with no choromatophores; ovaries orange; eggs yellowish orange.

Etymology. This small-sized alpheid shrimp is named after J. R. R. Tolkien’s dwarf character “Gimli” due to its relatively small size and notably hairier appearance compared to most other Salmoneus species.

Type locality. New Ireland, Bismarck Sea , Papua New Guinea (present study) .

Remarks. Two characters, 1) the presence of a subminor cheliped, and, 2) a major cheliped with the cutting edges of fingers bearing noticeable gaps between some or all teeth, are shared by S. gimlii sp. nov. and several other Salmoneus species, including S. sketi Fransen, 1991 ; S. erasimorum Dworschak, Anker and Abed-Navandi, 2000 ; S. paulayi Anker, 2011 ; S. poupini Anker, 2011 ; S. komaii Anker, 2011 ; S. yoyo Anker, Firdaus and Pratama, 2014 ; and S. secundus sp. nov. Yet, S. gimlii sp. nov. can be separated from all these species by a dorsally setose body with short and relatively thick setae, a small rostrum and orbital teeth distinctly falling short of the distal margin of the first antennular article, and meri of both chelipeds being slender proximally and abruptly widened before midlength.

The armature of the major cheliped fingers in S. gimlii sp. nov. closely resembles mostly that of the eastern Atlantic S. erasimorum . However, besides the three highlighted differences, the major cheliped fingers in S. gimlii sp. nov. bear two teeth on the cutting edge of the dactylus and one on the pollex in the distal half, while S. erasimorum has four and three teeth, respectively. Moreover, the general armature of the subminor cheliped fingers differs significantly between these two species (compare Fig. 2E View FIGURE 2 with figs 44, 45 in Dworschak et al. 2000).

Three species, S. paulayi , S. poupini and S. komaii , can be readily distinguished from the new species by their unique shape of the major cheliped (see Anker 2011, figs. 2A–F, 4, 6A–C, 9A–D, 10C) apart from the aforementioned differences. The remaining three species, S. sketi , S. yoyo and S. secundus sp. nov. are also quite distinct from S. gimlii sp. nov. and other Salmoneus species (see the remark section under S. secundus sp. nov., below; Anker et al. 2014 for S. yoyo ; and Fransen 1991 for S. sketi ).