Salmoneus poupini Anker, 2011

Anker, Arthur, 2022, Three new species of the shrimp genus Salmoneus Holthuis, 1955 from the Red Sea, with a new record of S. poupini Anker, 2010 (Malacostraca: Decapoda Alpheidae), Zootaxa 5138 (3), pp. 261-282 : 275-281

Salmoneus poupini Anker, 2011

( Figs. 10–13 )

Salmoneus poupini Anker 2011: 78 , figs. 8–11.

Material examined. 1 non-ovig. specimen (cl 4.6 mm), FLMNH UF 36068 , Red Sea , off Thuwal , Shib Nazar East Reef , 22°19'19.2"N, 38°51'18.0"E, offshore coral reef, under coral rubble on sand, depth: less than 15 m, leg. A. Anker et al., 16.03.2013 [fcn BDJRS-2828]; 1 ovig. specimen (cl 3.9 mm), FLMNH UF 36994 , Red Sea, Saudi Arabia, Farasan Islands, Zahrat Durakah, 16°50'09.2"N, 42°18'22.7"E, fringing reef and slope around large sand bank, under massive corals and coral rubble, depth: 2–6 m, leg. A. Anker et al., 11.03.2013 [fcn BDJRS-2678]; 1 non-ovig. specimen (cl 3.2 mm) FLMNH UF 35987 , Red Sea, Saudi Arabia, northern Farasan Banks off Al-Lith, Whale Shark Reef, 20°07'01.2"N, 40°12'54.0"E, coral reef, under coral rubble on sand, depth: 10 m, leg. A. Anker et al., 22.03.2013 [fcn BDJRS-3166]; 1 ovig. specimen (cl 4.1 mm), FLMNH UF 35984 , same collection data as for previous specimen [fcn BDJRS-3162] .

Comparative material. Salmoneus komaii Anker 2011 : ovig. female (cl 5.0 mm), FLMNH UF 23995 , French Polynesia, Society Islands , Moorea, Papetoai, fringing reef with large massive corals and coral rubble, under coral rubble, depth: 0.5–1.5 m, leg. A. Anker et al., 14.11.2009 [fcn BMOO-08996].

Description. See Anker (2011). Complementary illustrations of the Red Sea material are provided in Figs. 10–13 and discussed below.

Colour in life. Semi-transparent whitish; yellow-orange inner organs visible due to translucence of carapace; fresh eggs bright yolk-yellow ( Figs. 11–13 ; Anker 2011).

Type locality. Moorea , French Polynesia .

Distribution. Indo-West Pacific, apparently widespread from the Red Sea ( Saudi Arabia: off Thuwal, off Al-Lith, Farasan Islands) to the Philippines (Panglao) and French Polynesia (Moorea) ( Anker 2011; present study).

Ecology. Coral reef flats and coral reefs; under coral rubble and massive corals, at a depth range of 1– 15 m.

Remarks. The herein reported material of S. poupini from the Red Sea represents a significant extension of the species’ previously known distributional range from the western and central-western Pacific to the north-western Indian Ocean. The Saudi Arabian material of S. poupini is somewhat heterogeneous, especially in the size and proportions of the chelipeds, the armature of the cheliped fingers, and the shape of the rostrum. Similar variation was noted by Anker (2011) for the type series of this species. The largest specimen in the Saudi Arabian material, a non-ovigerous specimen (cl 4.6 mm) from the Thuwal reefs (FLMNH UF 36068), and the ovigerous specimen (cl 3.9 mm) from Zahrat Durakah in the Farasan Islands (FLMNH UF 36994), agree with the type specimens of S. poupini from French Polynesia in most morphological features, including the elongate carpus of the major cheliped and the armature of the cutting edges of the major chela fingers consisting of either five widely spaced teeth (former specimen, as in the holotype, Fig. 10f ) or four teeth (latter specimen, as in most paratypes and a non-type specimen from the Philippines) ( Anker 2011). The smallest specimen of S. poupini from Saudi Arabia, a non-ovigerous specimen (cl 3.2 mm), and another ovigerous specimen (cl 4.1 mm), both from the Whale Shark Reef in the Farasan Banks (FLMNH UF 35987, 35984), have much shorter and stouter chelipeds, although still with four teeth on the finger cutting edges of the major chela ( Fig. 10c ). The variation in the number of teeth on the finger cutting edges of the major chela appears to be correlated with the general proportions of the major chela, especially the length of the fingers. In specimens with five teeth, the fingers are comparatively longer, about 1.4–1.5 times as long as the palm ( Fig. 10f ; Anker 2011: fig. 10C), whereas in specimens with four teeth, they are somewhat shorter, about 1.1–1.2 times as long as the palm ( Fig. 10c ; Anker 2011: fig. 9B, D). The variation also affects the minor cheliped, with the smallest Saudi Arabian specimen (cl 3.2 mm, FLMNH UF 35987) having stouter, more curved fingers ( Fig. 10e , compare with the paratype from French Polynesia in Anker 2011: fig. 9G). In one of the ovigerous specimens (cl 4.1 mm, FLMNH UF 35984), the minor cheliped is relatively smaller in size (compared to other specimens of similar size) and has a weak armature on the fingers. The ischial armature of the chelipeds and second pereiopod, consisting of one spiniform seta, is present in all specimens from Saudi Arabia, as in the type specimens ( Anker 2011).

The shape and length of the rostrum in S. poupini also appears to be variable. The smallest specimen (FLMNH UF 35987) has a short, somewhat descending rostrum ( Fig. 10a ), reaching to the mid-length of the second article of the antennular peduncle (visible in Fig. 12b, c ), almost approaching the condition found in the related S. komaii Anker 2011 ( Anker 2011: figs. 5B, 8B). However, S. komaii ( Fig. 14 ) differs from S. poupini in the armature of the major chela fingers, the presence of small lateral lobe on the eye cornea, the relative length ratio of the posterior spiniform setae on the telson, and several other features ( Anker 2011). In the other three Saudi Arabian specimens of S. poupini , the rostrum is much longer, reaching or slightly overreaching the distal margin of the second article of the antennular peduncle (FLMNH UF 35984, 36994) or even exceeding the distal margin of the third article of the antennular peduncle (FLMNH UF 36068), and is therefore more similar to the rostrum of the holotype and most paratypes ( Anker 2011). Noteworthy, the distributional range of S. komaii in the western Pacific is herein extended from the Mariana Islands to French Polynesia.

Since the morphological variation in S. poupini affects both the type series and the Red Sea material, DNA analyses of all known material of S. poupini will be required to confirm that only one species is involved, as hypothetised here and by Anker (2011). Nevertheless, it must be noted that unusual morphological variation of the chelipeds and/or rostro-orbital area was also reported in several other species of the genus, such as S. seticheles , S. durisi and S. sketi Fransen, 1991 ( Fransen 1991; Anker 2003; Anker & Ashrafi 2019).

Figures

FIGURE 10. Salmoneus poupini Anker, 2011: non-ovigerous specimen (cl 3.2 mm) from the northern Farasan Banks off Al- Lith, Saudi Arabia (FLMNH UF 35987) [a-e]; non-ovigerous specimen (cl 4.6 mm) from Shib Nazar East Reef off Thuwal, Saudi Arabia (FLMNH UF 36068) [f]: a—frontal margin of carapace, lateral; b—right (major) cheliped, lateral; c—same, carpus and chela, dorsomesial; d—left (minor) cheliped, lateral [detached]; e—same, carpus and chela, ventrolateral; f—right (major) cheliped, carpus and chela, mesial.

FIGURE 11. Salmoneus poupini Anker, 2011, non-ovigerous specimen (cl 4.6 mm) from Shib Nazar East Reef off Thuwal, Saudi Arabia (FLMNH UF 36068): a—shrimp in life, dorsal; b—same, lateral. Photographs by the author.

FIGURE 12. Salmoneus poupini Anker, 2011, non-ovigerous specimen (cl 3.2 mm) from the northern Farasan Banks off Al- Lith, Saudi Arabia (FLMNH UF 35987): a—shrimp in life, dorsal; b, c—same, lateral (right and left, respectively). Photographs by the author.

FIGURE 13. Salmoneus poupini Anker, 2011: ovigerous specimen (cl 3.9 mm) from the Farasan Islands, SaudiArabia (FLMNH UF 36994) [a]; ovigerous specimen (cl 4.1 mm) from the northern Farasan Banks off Al-Lith, SaudiArabia (FLMNH UF 35984) [b]: a—shrimp in life, lateral; b—same, lateral. Photographs by the author.

FIGURE 14. Salmoneus komaii Anker, 2011: ovigerous specimen (cl 5.0 mm) from Moorea, French Polynesia (FLMNH UF 23995), shrimp in life, lateral. Photograph by the author.