Revision of Salmoneus cristatus (Coutière, 1897) and Allied Forms (Decapoda: Caridea: Alpheidae)

© 2023 Academia Sinica, Taiwan Open Access Revision of Salmoneus cristatus (Coutière, 1897) and Allied Forms (Decapoda: Caridea: Alpheidae) Hossein Ashrafi1,*, Arthur Anker2,3 , and Zdeněk Ďuriš1 1Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, CZ-71000, Ostrava, Czech Republic. *Correspondence: E-mail: [email protected] (Ashrafi) E-mail: [email protected] (Ďuriš) 2Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia. E-mail: [email protected] (Anker) 3Universidade Federal de Pelotas, Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Campus Universitário Capão do Leão, RS, 96010-610, Brazil Received 28 June 2022 / Accepted 4 September 2023 / Published 13 December 2023 Communicated by Ka Hou Chu Salmoneus cristatus (Coutière, 1897) is one of the first described species in the alpheid genus Jousseaumea Coutière, 1897, a name later invalidated and replaced by Salmoneus Holthuis, 1955. The species was described based on material from Djibouti and was initially characterised by the presence of a pronounced, posteriorly extending carina on the mid-dorsal line of the carapace, a shoulder-like elevation of the orbital hoods, and a red-banded colour pattern. Relying mainly on morphological features, various authors reported S. cristatus from several localities in the Indo-West Pacific, from the Red Sea to southern China and Australia. However, recently collected material attributable to S. cristatus on morphological grounds allowed for the combination of morphological characters, molecular data and colour patterns, demonstrating the existence of at least four species under the name of S. cristatus, including three species that are morphologically similar to, but phylogenetically distant from S. cristatus s. str. Therefore, S. cristatus is redescribed herein based on recent material from Saudi Arabia and Iran, as well as older material from Israel and Madagascar, with designation of a neotype from the Red Sea coast of Saudi Arabia. Three new species, viz. S. paracristatus sp. nov., S. franseni sp. nov., and S. alius sp. nov., are described based on recent material from Papua New Guinea for the former two species, and New Caledonia, Papua New Guinea and the Solomon Islands for the latter species. However, at least two of these new species seem to have wider distributions in the Indo-West Pacific. Key words: Marine biodiversity, Alpheid shrimps, Salmoneus, Phylogeny, Indo-West Pacific, New species Citation: Ashrafi H, Anker A, Ďuriš Z. 2023. Revision of Salmoneus cristatus (Coutière, 1897) and allied forms (Decapoda: Caridea: Alpheidae). Zool Stud 62:53. doi:10.6620/ZS.2023.62-53. BACKGROUND The caridean shrimp genus Salmoneus Holthuis, 1955 is presently the third largest genus in the family Alpheidae Rafinesque, 1815, with over 60 described species so far (Coutière 1897a b; De Grave and Fransen 2011; Anker 2022; Komai 2022). However, the actual species diversity of the genus appears to be far beyond what is currently known, considering the presence of numerous morphologically nearly identical species, the rapidly growing number of described species in the genus, and the fact that about two-thirds of all the species have been described in the past two decades (e.g., Anker 2010; Komai and Anker 2012; Anker and Lazarus 2015; Anker 2019b; Anker and Ashrafi 2019; Anker et al. 2020; Marin 2021; Anker 2022; Komai 2022). The reason for this hidden diversity lies in these shrimps’ small size and cryptic lifestyles, ranging from dwelling in small spaces under large boulders or in coral rubble crevices (Anker and Marin 2006; Anker 2011 2019a 2020; Ashrafi et al. 2020) to living in burrows of various fossorial animals (e.g., De Grave 2004; Komai Zoological Studies 62:53 (2023) doi:10.6620/ZS.2023.62-53 1 © 2023 Academia Sinica, Taiwan 2009; Anker et al. 2014; Komai et al. 2021; d’Acoz et al. 2022), or in marine caves (Fransen 1991; Komai et al. 2015). Salmoneus was subdivided into seven informal groups by Anker and Marin (2006), of which the S. cristatus (Coutière, 1897) group was defined by possession of a prominent mid-dorsal carina of variable posterior extension, and each of the major cheliped fingers being serrated, i.e., armed with small, bluntly triangular teeth, on almost the entire cutting edge. The following species were originally assigned to the S. cristatus group, in addition to the group-nominal species: S. auroculatus Anker and Marin, 2006; S. brevirostris (Edmondson, 1930); and S. tricristatus Banner, 1959 (Anker and Marin 2006). Later, S. chadwickae Ďuriš and Horká 2016 was added to the S. cristatus group, thus resulting in five species presently assigned to this group (Ďuriš and Horká 2016). Within the S. cristatus group, S. cristatus is characterized by a striking, redbanded colour pattern, as described very briefly by Coutière (1987b 1899) and in more detail by L.B. Holthuis in Banner and Banner (1981), and by Banner and Banner (1983). The species is also morphologically rather distinctive, defined by the so called “shoulder” of the anterior region of the carapace, and somewhat elevating the orbital hoods (Coutière 1897b 1899; Banner and Banner 1981). Salmoneus cristatus is one of the three species originally described by Coutière (1897a b) under the generic name Jousseaumea Coutière, 1897, the others being the type species S. serratidigitus (Coutière, 1897) and S. latirostris (Coutière, 1897). In the original description of S. cristatus from Djibouti, Coutière (1897b) did not provide any illustrations. However, some additional details and a few drawings were provided in a subsequent publication (Coutière 1899). Since the original account of the species, S. cristatus has been recorded from several localities throughout the Indo-West Pacific, including the Red Sea (Holthuis 1958; Banner and Banner 1981; Ďuriš and Horká 2016), East Africa (Bruce 1976; Banner and Banner 1983), Thailand (Banner and Banner 1966), Taiwan (Anker 2001, as S. cf. cristatus), eastern Australia (Anker 2003), Papua New Guinea (Ďuriš and Horká 2016, as S. aff. cristatus), and the South China Sea (Wang and Sha 2016; Sha et al. 2019). Importantly, Banner and Banner (1981) provided illustrations of the topotypic specimen of S. cristatus from Djibouti. Ďuriš and Horká (2016) provided the first molecular phylogeny of the S. cristatus group, which included S. chadwickae, S. auroculatus, S. tricristatus, and two species tentatively identified as S. aff. cristatus and S. aff. brevirostris. However, the significance of this phylogeny is limited, as no specimens matching S. cristatus sensu Coutière (1897b 1899) from the western Indian Ocean were available at that time. Nevertheless, a comparative analysis of morphology and colour of S. cristatus and related forms in Ďuriš and Horká (2016) strongly indicated that S. cristatus may represent more than one species. In the present study, morphological, ecological and molecular data are combined to perform a revision of S. cristatus and morphologically allied forms (see below). Firstly, the neotype of S. cristatus of Coutière (1897b) is designated, and the species is redescribed based on material from Iran and Saudi Arabia. The colour pattern of S. cristatus is illustrated for the first time. In addition, three new species are described based on material from Papua New Guinea (two species); and New Caledonia, Papua New Guinea, and the Solomon Islands (one species). Despite their morphological resemblance with S. cristatus, the herein described species markedly differ from S. cristatus by their live colours and are also phylogenetically distant from it. MATERIALS AND METHODS Material The specimens of Salmoneus reported in the present study were collected during several expeditions organised by the Muséum National d’Histoire Naturelle, Paris, France (MNHN), and the Florida Museum of Natural History, University of Florida, Gainesville, USA (FLMNH UF). The MNHN expeditions include the Our Planet Reviewed Madang Expedition (Papua New Guinea) in 2012 [AA, ZĎ], the Our Planet Reviewed Kavieng Expedition (Papua New Guinea) in 2014 [ZĎ], Koumac Expedition (New Caledonia) in 2018 and 2019 [AA, ZĎ], and Madibenthos Expedition (Martinique) in 2016 [ZĎ]. The FLMNH expeditions include the survey of the Thuwal Reefs (Red Sea coast of Saudi Arabia) in 2013 [AA], Moorea Biocode Project (French Polynesia) in 2008 and 2009 [AA], and the Solomon Islands in 2016 [AA]. Additional material was collected in Iran (Abu-Musa Island) in 2019 [HA] and Saudi Arabia (Rabigh) in 2022 [AA]. Two older museum specimens, one of them deposited in the MNHN and the other in the Naturalis Biodiversity Center, Leiden, the Netherlands (RMNH), were also examined. Carapace length (cl, in mm) was measured along the mid-dorsal line from the tip of the rostrum to the posterior margin of the carapace. DNA extraction, amplification, and sequencing Tissues from the pleonal muscles and/or posterior page 2 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan pleopods were used for total genomic DNA extraction using the DNeasy Blood and Tissue Isolation Kit (QIAGEN) following the manufacturer’s instructions. The PCR was performed on partial segments of two genes, i.e., the ribosomal 16S rRNA and mitochondrial CO1, using the pair primers Cari F/Cari R (AznarCormano et al. 2015) and JgLCO1490/JgHCO2198 (Geller et al. 2013), respectively. A total volume of 20 μl including 4 μl 5× MyTaq™ Red Reaction buffer (including 15 mM MgCl2 and 5 mM dNTPs), 1.2 μl DNA template, 13 μl ddH2O, 0.8 μl of each primer, and 0.2 μl MyTaq™ Red DNA polymerase were used for the PCR. The thermocycler conditions for amplifying both 16S and CO1 genes followed the protocol described in Ashrafi et al. (2022). The PCR products were purified using the GenElute PCR Clean-up kit (Sigma-Aldrich). The final products were sent to Macrogen, Amsterdam, the Netherlands, for forward and in some cases reverse sequencing (by an ABI3730XL DNA Sequencer). GenBank accession numbers for all newly created sequences (most of the material reported in this study) are provided in table 1. In addition to the specimens examined, subsampled and sequenced as part of this study, sequences of other species of the genus Salmoneus available on GenBank, including several members of the S. cristatus group, were included in the molecular analysis (Ďuriš and Horká 2016; Ashrafi et al. 2022; Komai 2022; see also Table 1). Sequence alignment, pairwise distance analysis, and tree reconstruction Obtained sequences were checked by eye using Chromas ver. 2.4.1 and then aligned by the software MUSCLE (Edgar 2004) implemented in MEGA-X (Kumar et al. 2018) with default parameters. For the non-protein coding gene, the partial fragment of 16S, the highly variable positions were eliminated from the alignments using Gblocks v0.91b (Castresana 2000) with default settings, except for allowing gap positions and less strict flanking positions. Pairwise distance analysis (p-distance) was conducted using the aligned CO1 gene dataset (~600 bp) in MEGA-X with default parameters. The best model of nucleotide substitution was selected based on BIC (Bayesian Information Criterion) using the software IQ-TREE ver. 2.0.5 (Kalyaanamoorthy et al. 2017). The maximum likelihood analysis was conducted with the software IQ-TREE ver. 2.0.5, whereas the Bayesian tree was constructed using MrBayes ver. 3.2.7 (Ronquist and Huelsenbeck 2003). The MCMC analysis was set for 18 × 106 generations with four chains and two independent runs with a sampling frequency of 2500 for each run; at the end, the first 25% of trees were discarded as “burnTable 1. Salmoneus species used for sequencing and phylogenetic analysis. Collection information including country, collection numbers, GenBank accession numbers and references are provided Species Country Collection number GenBank Accession numbers 16S/CO1 References S. aduncus Komai, 2022 Japan CBM-ZC 17107 LC731708/- Komai (2022) S. alius sp. nov./HT New Caledonia MNHN-IU-2019-3495 OR438949/ OR438993 Present study S. alius sp. nov./PT PNG MNHN-IU-2013-1471 OR485163/- Present study S. alius sp. nov./PT Solomon Islands FLMNH-UF-60000 OR485164/- Present study S. auroculatus Anker & Marin, 2006 PH/Panglao OUMNH.ZC.2015-01-031 KR527200/ KT192564 Ďuriš and Horká (2016) S. chadwickae Ďuriš & Horká, 2016/HT RS/Jordan OUMNH.ZC.2015-02-01 KP462861/ KT192561 Ďuriš and Horká (2016) S. cristatus (Coutiere, 1897) RS/Saudi Arabia FLMNH-UF-68811 OR438956/ OR438996 Present study S. cristatus (Coutiere, 1897)/NT RS/Saudi Arabia FLMNH-UF-36069 OR438955/- Present study S. cristatus (Coutiere, 1897) PG/Iran MNHN-IU-2019-3851 OR438948/ OR438991 Present study S. franseni sp. nov./HT PNG MNHN-IU-2014-881 OR438950/ OR438994 Present study S. franseni sp. nov. PNG MNHN-IU-2014-933 OR438952/ OR438998 Present study S. paracristatus sp. nov./HT PNG MNHN-IU-2014-199 OR438951/ OR438995 Present study S. paracristatus sp. nov./PT1 PNG MNHN-IU-2014-205 KP462859/ OR438990 Ďuriš and Horká (2016), Present study S. paracristatus sp. nov./PT2 PNG MNHN-IU-2014-294 KP462858/- Ďuriš and Horká (2016) S. setosus Manning & Chace, 1990 FA/Martinique MNHN-IU-2016-4648 OR438953/ OR438992 Present study S. shojaei Ashrafi, Anker & Ďuriš, 2022 PG/Iran MNHN-IU-2014-1257 ON128267/ ON128447 Ashrafi et al. (2022) S. tricristatus A.H. Banner, 1959 FP/Moorea FLMNH-UF-24069 OR438954/ OR438997 Present study Abbreviations used: FA, French Antilles; FP, French Polynesia; PG, Persian Gulf; PH, Philippines; PNG, Papua New Guinea; RS, Red Sea; HT, holotype; NT, neotype; PT, paratype. page 3 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan in”. The online application ITOL (Letunic and Bork 2011) was used for displaying the final trees. The phylogenetic tree was constructed for 15 specimens belonging to 10 species (Table 1), based on concatenation of two genes, 16S rRNA (488 bp) and mtCO1 (614 bp). It is important to note that this tree was built exclusively for taxonomic purposes, i.e., to show genetic divergence between the specimens preliminarily identified as S. cristatus, and does not reflect the actual phylogenetic relationships between the 10 species included in the analysis. The voluntary omission of numerous distantly related taxa explains the low support for deeper branches of the tree. A more comprehensive phylogeny of Salmoneus and related genera will be provided elsewhere (Ashrafi et al. in preparation). RESULTS All specimens examined present a prominent middorsal carina extending from the tip of the rostrum at least to the level of the eyes. However, in most cases, this carina extends beyond the middle of the carapace. All individuals are also characterised by the anterior region of the carapace having a distinct “shoulder”, individualising the orbital hoods area from the rest of the carapace. However, some minor but seemingly consistent morphological differences between the western Indian Ocean (Saudi Arabia, Iran) and western Pacific (Papua New Guinea, New Caledonia, Solomon Islands) specimens, and also within the western Pacific material, were corroborated by our molecular results (see below). These differences affect, for instance, the posterior extension of the mid-dorsal carina, the configuration of the dentition of the major chela fingers, and the armature of the ischia of the third and fourth pereiopods (see below). In addition, only the western Indian Ocean specimens display bright red bands, as described for S. cristatus (Coutière 1899; Holthuis 1958), in contrast to the plain, creamy whitish or yellowish colour of the western Pacific individuals (see below). The combined 16S + CO1 phylogenetic tree (Fig. 1) revealed the presence of four clades within the material initially identified as S. cristatus (or S. aff. cristatus). Each of these four clades clearly corresponds to a genetically distinctive lineage, with a minimal pairwise genetic distance of 9.1% for COI (Table 2). The three specimens from the western Indian Ocean clustered together as a sister clade of S. tricristatus Banner, 1959, whereas the specimens from the western Fig. 1. Bayesian and Maximum Likelihood concatenated tree (based on 16S and COI ) of selected species of Salmoneus with focus on the S. cristatus species group, showing two different clades morphologically allied to S. cristatus. Numbers above or under each branch are bootstrap supports and Bayesian posterior probabilities, respectively (supports and probabilities under 60/0.6 are not shown). Insert photographs show S. franseni sp. nov. (yellow clade) and S. cristatus (red clade). Abbreviations used: FA, French Antilles; FP, French Polynesia; PG, Persian Gulf; PH, Philippines; PNG, Papua New Guinea; RS, Red Sea; HT, holotype; NT, neotype; PT, paratype. Sequences for S. aduncus, S. auroculatus, S. chadwickae, and S. shojaei were obtained from GenBank (see Ďuriš and Horká 2016; Komai 2022; Ashrafi et al. 2022). page 4 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Pacific formed a clade containing three genetically welldifferentiated lineages, though in a more distant position (Fig. 1). Therefore, the two most typical features of the carapace of S. cristatus, namely the strong, posteriorly extending mid-dorsal carina and the “shoulder” of the anterior region, seem to have evolved at least twice. These results, albeit preliminary, also indicate that the S. cristatus group as defined by Anker and Marin (2006) may not be monophyletic, as it includes S. aduncus from the S. rostratus group and S. shojaei, which was tentatively assigned to the S. gracilipes group (Komai 2022; Ashrafi et al. 2022). Based on the morphological and molecular results, the specimens from the Red Sea (Saudi Arabia) and Persian Gulf (Iran) clearly represent S. cristatus sensu Coutière (1897b 1899), whereas the material from Papua New Guinea, New Caledonia, and the Solomon Islands is assigned to three new species, which are described below as S. franseni sp. nov., S. paracristatus sp. nov., and S. alius sp. nov. (Fig. 1). Within S. cristatus, the genetic distance of CO1 between the Red Sea and Persian Gulf specimens is minimal (1.0%, Table 2) and expected considering the geographic distance between these populations. On the other hand, the holotype of S. franseni sp. nov., was genetically more significantly different from the non-type specimen from the same locality (pairwise genetic distance of CO1 3.8%), which was tentatively attributed to the same species for it is missing its major cheliped. RESULTS TAXONOMY Order Decapoda Latreille, 1802 Family Alpheidae Rafinesque, 1815 Genus Salmoneus Holthuis, 1955 Salmoneus cristatus (Coutière, 1897) (Figs. 2–5) Jousseaumea cristata Coutière 1897a: 234; Coutière 1899: 70, figs. 22, 23. Salmoneus cristatus — Holthuis 1958: 18, fig. 7; (?) Bruce 1976: 44; Banner and Banner 1981: 54, fig. 6: Banner and Banner 1983: 88 (part.). Not Salmoneus cristatus — Banner and Banner 1983: 88 [= S. chadwickae Ďuriš and Horká, 2016 or S. auroculatus Anker and Marin, 2006, see below]. Not Salmoneus cristatus — Anker 2003: 108, fig. 6 [possibly = S. franseni sp. nov., see below]. Not Salmoneus cristatus — Wang and Sha 2016: 1586, figs. 1–4 [= S. paracristatus sp. nov., see below] Not Salmoneus cristatus — Sha, Wang, and Cui 2019: 206, figs 2.121–2.124 [= S. paracristatus sp. nov., see below] Not Salmoneus cristatus — Banner and Banner 1966: 40, fig. 10 [possibly = S. paracristatus sp. nov., see below]. Material examined: Neotype: ovig. specimen (cl 2.5 mm), FLMNH UF 36069, Red Sea, Saudi Arabia, off Thuwal, Shib Nazar East, 22°19'19.94"N, 38°51'17.99"E, coral reef, depth 0  20 m, coll. A. Anker et al., 16.03.2016 (BDJRS-2832). Additional material: 1 non-ovig. specimen (cl 2.9 mm), FLMNH UF 68811, Red Sea, Saudi Arabia, north of Rabigh, 22°55'32.17"N, 38°51'21.45"E, back reef, shallow lagoon with sand and coral rubble, in coral rubble crevices, hand and hammer, depth 1 m, coll. A. Anker et al., 23.06.2022 (AA-22140); 1 ovig. specimen (cl 3.5 mm), RMNH.CRUS. D.14354, Red Sea, Gulf of Aqaba, Israel, 03.12.1955, coll. H. Steinitz; 1 ovig. specimen (cl 3.3 mm), MNHNIU-2019-3851, Persian Gulf, Iran, Abu-Musa Island, Qadir Park, sandy/rocky bottom with corals, shallow subtidal (depth less than 2 m), 17.07.2019, coll. H. Ashrafi; 1 ovig. specimen (cl 3.2 mm), MNHNIU-2019-3852, same data as for previous specimen; Table 2. Pairwise distance matrix of partial fragment of CO1 (bottom half) and 16S (top half) for S. cristatus, S. paracristatus sp. nov., S. franseni sp. nov., and S. alius sp. nov. species 1 2 3 4 5 6 7 8 9 10 1) S. alius sp. nov (HT) 0.002 0.004 0.045 0.047 0.047 0.032 0.033 0.032 0.032 2) S. alius sp. nov (PNG) - 0.002 0.043 0.044 0.045 0.030 0.031 0.030 0.030 3) S. alius sp. nov (SI) - - 0.045 0.047 0.047 0.032 0.033 0.032 0.032 4) S. cristatus (PG/Iran) 0.155 - - 0.002 0.002 0.049 0.051 0.045 0.045 5) S. cristatus (RS/Saudi Arabia) 0.156 - - 0.010 0.005 0.051 0.051 0.047 0.047 6) S. cristatus (NT) - - - - 0.051 0.053 0.047 0.047 7) S. franseni sp. nov. 0.137 - - 0.150 0.152 - 0.007 0.026 0.026 8) S. franseni sp. nov. (HT) 0.153 - - 0.168 0.166 - 0.038 0.027 0.027 9) S. paracristatus (HT) 0.135 - - 0.182 0.181 - 0.095 0.107 0.000 10) S. paracristatus (PT) 0.140 - - 0.184 0.182 - 0.091 0.107 0.005 Abbreviations used: PG, Persian Gulf; RS, Red Sea; SI, Solomon Islands; HT, holotype; PT, paratype; NT, neotype. page 5 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan 1 ovig. specimen (cl 4.4 mm), MNHN-IU-2021-9769, Madagascar, Toliara (Tuléar), probably around 1977– 1979, coll. M. Peyrot-Clausade. Redescription: Small-sized alpheid shrimps (cl range 2.5–4.4 mm). Carapace (Fig. 3A–C) covered by short setae, with prominent mid-dorsal carina reaching to about distal fourth of carapace; frontal region entirely concealing eyes in dorsal view, distinctly elevated from anterolateral portion of carapace, shoulder-like; rostrum triangular in dorsal view, with subacute tip, reaching to about distal margin of second antennular article, approximately as long as broad; rostral carina prominent, continued by mid-dorsal carina on carapace; orbital teeth small, subacute, reaching to proximal third of first antennular article, distinctly longer than wide; anterolateral suture present, pterygostomial angle broadly rounded, cardiac notch deep. Pleon (Fig. 3E) covered with short setae; pleura of first to forth pleonites rounded anteroventrally and posteroventrally; fifth pleuron subrounded posteroventrally; sixth pleuron with subtriangular projection flanking each side of telson, posteroventral suture incomplete. Telson (Fig. 3D) subrectangular, tapering distally, about 4.5 times as long as distal width, covered by scattered short setae; dorsal surface with two pairs of spiniform setae located at about 0.5 and 0.8 telson length, respectively; posterior margin with broadly U-shaped, central notch furnished with 4 plumose setae, and two pairs of spiniform setae, mesial ones about 1.6 times as long as lateral ones and about 4 times as long as spiniform setae on dorsal surface. Antennule (Fig. 3B, C) with peduncle relatively stout; first article approximately as long as broad; stylocerite robust, with blunt tip, reaching to or slightly overreaching second article; second article about 0.8 times as long as broad; third article about 1.2 times as long as second article; lateral antennular flagellum biramous, fused portion with two subdivisions, shorter ramus well developed, reaching to about sixth subdivision of longer ramus, with six or so groups of aesthetascs. Antenna (Fig. 3B, C) with stout basicerite, its distoventral margin armed with subacute tooth and blunt subdistal projection, superior margin projecting as small subacute tooth; scaphocerite reaching to about middle of third article of antennular peduncle, lateral tooth slightly overreaching blade; carpocerite almost reaching distal margin of second article of antennular peduncle; flagellum not particularly stout, with second subdivision distinctly longer than others. Third maxilliped (Fig. 5A, B) with coxa bearing strap-like epipod and broadly rounded lateral plate; antepenultimate article slender, about six times as long as broadest part; penultimate article relatively short, about 0.5 times as long as antepenultimate article; ultimate article about twice as long as penultimate article, distally armed with small, subapical, spiniform seta; exopod slender, reaching to about distal margin of antepenultimate article; arthrobranch normally developed. First pereiopods (chelipeds) (Fig. 4) very different in size and shape. Major cheliped (Fig. 4A–D) robust, carried flexed under body when not in use; coxa with strap-like epipod and setobranch; ischium slender, four times as long as wide, unarmed ventrally; merus widening distally, about 2.3 times as long as ischium, with slightly concave ventral margin; carpus small, cupshaped; chela enlarged, swollen, as long as combination of basis to carpus; palm robust, about twice as long as wide, subcylindrical, slightly flattened dorsally and with shallow depression mid-dorsally and deep complex groove proximally, about 1.4 times as long as fingers; fingers relatively slender, slightly twisted, with strongly crossing fingertips, not gaping when closed; pollex with cutting edge armed with about 15 teeth, proximal fourth of cutting edge concave and with eight small teeth, distal three-fourths of cutting edge straight and with seven teeth enlarging towards distal margin; dactylus with deep depression on proximal third part of mesial surface accommodating convex margin of opposed margin of pollex, with 11 teeth on cutting edge enlarging in size towards distal margin. Minor cheliped (Fig. 4E, F) significantly smaller and weaker than major cheliped; coxa with strap-like epipod and setobranch; ischium slender, about four times as long as broad, unarmed ventrally; merus slender, slightly longer than ischium; carpus slightly shorter than merus, widening distally; chela simple, with palm approximately as long as fingers; cutting edges of fingers unarmed. Second pereiopod (Fig. 5C) moderately long, short, slender; coxa with strap-like epipod and setobranch; ischium about 6.5 times as long as wide, unarmed ventrally; merus slender, slightly longer than ischium; carpus 1.2 times as long as merus, with five subdivisions, proximal one as long as sum of others; chela about 0.3 times as long as carpus, palm and fingers subequal in length. Third pereiopod (Fig. 5D) moderately slender; coxa with strap-like epipod and setobranch; ischium slightly widening distally, about 2.6 times as long as wide, with small spiniform seta on ventrolateral surface; merus slightly inflated, about 1.6 times as long as ischium; carpus slenderer and slightly shorter than merus, eight times as long as wide, with small spiniform seta on distoventral margin; propodus slightly shorter than carpus, ventral margin armed with two spiniform setae in addition to distal pair of spiniform setae page 6 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 2. Salmoneus cristatus (Coutière, 1897), shrimps in life; A, B, ovigerous specimen (cl 3.3 mm) from Abu-Musa Island, Iran (MNHNIU-2019-3851), in dorsal (A) and dorsolateral (B) views [photographs courtesy of Rashed Abdollahi]; C, D, neotype, ovigerous specimen (cl 2.5 mm) from Shib Nazar East reef off Thuwal, Saudi Arabia (FLMNH UF 36069), in dorsal (A) and dorsolateral (B) views [photographs by AA]. page 7 of 31 Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 3. Salmoneus cristatus Coutière, 1897, ovigerous specimen (cl 3.3 mm) from Abu-Musa Island, Iran (MNHN-IU-2019-3851): A, carapace, dorsal view; B, anterior region of carapace and frontal appendages, lateral view; C, same, dorsal view; D, telson and uropods, dorsal view; E, posterior pleonites, telson and right uropod, lateral view. page 8 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 4. Salmoneus cristatus Coutière, 1897, ovigerous specimen (cl 3.3 mm) from Abu-Musa Island, Iran (MNHN-IU-2019-3851): A, left (major) cheliped, lateral view; B, same, chela, lateral view; C, same, mesial view; D, same, distal half of palm and fingers open, lateral view; E, right (minor) cheliped, lateral view. page 9 of 31 Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 9. Salmoneus paracristatus sp. nov., holotype, non-ovigerous specimen (cl 2.9 mm) from New Ireland, Papua New Guinea (MNHNIU-2014-199): A, third maxilliped, lateral view; B, same, ultimate article, mesial view; C, second pereiopod, lateral view; D, third pereiopod, lateral view; E, fourth pereiopod, lateral view. page 16 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan long as propodus. Fourth pereiopod (Fig. 9E) generally similar to third one but slightly slenderer; propodus armed with four spiniform setae on ventral margin in addition to distal pair. Fifth pereiopod missing. Uropods (Fig. 7D) with lateral lobe of protopod broadly triangular; exopod ovate, anterolateral margin with small triangular tooth adjacent to relatively stout spiniform seta, diaeresis sinuous; endopod slightly longer than exopod, ovoid, without specific feature. Colour in life: Body largely translucent with fawnyellow tinge; pleon with faint, buff-yellow, transverse bands; antennular and antennal flagella pale orange; major cheliped hyaline white with orange-yellow tinge on fingers; remaining appendages colourless or with buff-yellow tinge (Fig. 6). Type locality: Papua New Guinea (present study). Distribution: Papua New Guinea: New Ireland (Ďuriš and Horká 2016, as S. aff. cristatus; present study); possibly Australia: Ashmore Reef off Queensland (Anker 2003, as S. cristatus). Salmoneus franseni sp. nov. (Figs. 10–13) urn:lsid:zoobank.org:act:A78DCC3C-0544-44B0-A08663040293219A Salmoneus aff. cristatus — Ďuriš and Horká 2016: 783 (part.) [not S. cristatus (Coutière, 1897)]. Salmoneus cristatus — Wang and Sha 2016: 1586, figs. 1–4 [not S. cristatus (Coutière, 1897)]. Salmoneus cristatus — Sha, Wang, and Cui 2019: 206, figs 2.121– 2.124 [not S. cristatus (Coutière, 1897)]. (?) Salmoneus cristatus — Banner and Banner 1966: 40, fig. 10 [not S. cristatus (Coutière, 1897)]. Material examined: Holotype: non-ovig. specimen (cl 3.2 mm), MNHN-IU-2014-881, Papua New Guinea, Kavieng 2014 expedition, sta. KB60, 2°32'30"S, 150°35'18"E, sand and coarse rubble, brushing of dead corals, depth 20 m, coll. MNHN team, 23.06.2014. Additional material: 1 non-ovig. specimen (cl 2.7 mm), MNHN-IU-2014-933, same collection data as for holotype (see discussion below). Etymology: The species is named after Dr. Charles H.J.M. Fransen (Naturalis Biodiversity Center, Leiden) for his major contribution to taxonomy of caridean shrimps, including description of a peculiar cave species of Salmoneus (Fransen 1991). Description: Small-sized alpheid shrimps (cl 3.2 mm in holotype). Carapace (Fig. 11A–C) with prominent mid-dorsal carina reaching to about posterior fourth of carapace; frontal region fully concealing eyes in dorsal view, mid-dorsal carina prominent and reaching to about posterior fourth of carapace, distinctly elevated from anterolateral portion of carapace, shoulder-like; rostrum triangular in dorsal view, with subacute tip, reaching to about distal margin of second antennular article, as long as broad, rostral carina prominent, continued by mid-dorsal carina on carapace; orbital teeth small, subacute, as long as broad; anterolateral suture present, pterygostomial angle broadly rounded, cardiac notch deep. Pleon (Fig. 11D) scarcely furnished with fine setae; pleura of first to third pleonites rounded anteroventrally and posteroventrally; fourth pleuron subrounded posteroventrally; fifth pleuron with small subacute projection posteroventrally; sixth pleuron with small subacute projection flanking each side of telson, posteroventral suture incomplete. Telson (Fig. 11D, E) sub-rectangular, tapering distally, about 4.3 times as long as distal width, proximal margin about twice as broad as distal margin; dorsal surface with two pairs of spiniform setae located at about 0.5 and 0.8 telson length, respectively; posterior margin with broadly U-shaped, central notch furnished with two plumose setae, and two pairs of spiniform setae, mesial pair about 1.5 times as long as lateral one and about four times as long as spiniform setae on dorsal surface. Antennule (Fig. 11B, C) with peduncle relatively stout; first antennular article approximately as long as broad, stylocerite relatively robust, with blunt tip, reaching to about distal margin of second article; second article about 1.6 times as broad as long; third article about 1.6 times as long as second article, slightly longer than wide; lateral antennular flagellum biramous, fused portion composed of one subdivision, shorter ramus well-developed, reaching to about ninth subdivision of longer ramus, with eight or so groups of aesthetascs. Antenna (Fig. 11B, C) with stout basicerite, its distoventral margin armed with subacute tooth and blunt subdistal projection, superior margin projecting as small subacute tooth; scaphocerite reaching to about mid-length of third antennular article, blade slightly surpassing lateral tooth; carpocerite stout, slightly overreaching second antennular article. Third maxilliped (Fig. 13A, B) with coxa bearing strap-like epipod and broadly rounded lateral plate; antepenultimate article slender, about nine times as long as proximal width; penultimate article relatively short, about 0.3 times as long as antepenultimate article; ultimate article about twice as long as penultimate article, distally armed with two subapical spiniform setae; exopod slender, reaching to about distal margin of antepenultimate segment; arthrobranch normally developed. First pereiopods (Fig. 12) very different in size and shape. Major cheliped (Fig. 12A–D) robust, carried flexed under body when not in use; coxa with straplike epipod and setobranch; ischium relatively slender, page 17 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan about 4.3 times as long as proximal width, unarmed ventrally; merus slightly widening distally, about twice as long as ischium, ventral margin somehow flattened; carpus vase-shaped; chela enlarged, swollen, as long as combination of basis to carpus; palm robust, about 1.7 times as long as wide, subcylindrical, slightly flattened dorsally and with shallow depression mid-dorsally and deep complex groove proximally, approximately as long as fingers; fingers with strongly crossing fingertips, without gap when closed, with nine (dactylus) or 10 (pollex) evenly distributed teeth slightly enlarging towards distal margin; dactylus without concavity on proximal part of mesial surface. Minor cheliped (Fig. 12E, F) significantly smaller and weaker than major cheliped; coxa with strap-like epipod and setobranch; ischium slender, about 4.5 times as long as midwidth, unarmed ventrally; merus slightly swollen, slightly longer than ischium; carpus slightly longer than merus, widening distally; chela simple, with palm approximately as long as fingers, cutting edge of fingers unarmed. Second pereiopod (Fig. 13C) slender; coxa with strap-like epipod and setobranch; ischium slender, about eight times as long as broad, unarmed ventrally; merus slender, as long as ischium; carpus slender, 1.5 times as long as merus, with five subdivisions, proximal Fig. 10. Salmoneus franseni sp. nov., holotype, non-ovigerous specimen (cl 3.2 mm) from New Ireland, Papua New Guinea (MNHN-IU-2014-881), shrimp in life in dorsolateral (A) and lateral (B) views [photographs by ZĎ]. page 18 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 11. Salmoneus franseni sp. nov., holotype, non-ovigerous specimen (cl 3.2 mm) from New Ireland, Papua New Guinea (MNHN-IU-2014-881): A, carapace, dorsal view; B, anterior region of carapace and frontal appendages, lateral view; C, same, dorsal view; D, posterior pleonites, telson and left uropod, lateral view; E, telson, dorsal view. page 19 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 12. Salmoneus franseni sp. nov., holotype, non-ovigerous specimen (cl 3.2 mm) from New Ireland, Papua New Guinea (MNHN-IU-2014-881): A, right (major) cheliped, lateral view; B, same, chela, mesial view; C, same, lateral view; D, same, distal portion of palm and fingers slightly open, lateral view; E, left (minor) cheliped, lateral view; F, same, chela, mesial view. page 20 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 13. Salmoneus franseni sp. nov., holotype, non-ovigerous specimen (cl 3.2 mm) from New Ireland, Papua New Guinea (MNHN-IU-2014-881): A, third maxilliped, lateral view; B, same, ultimate article, mesial view; C, second pereiopod, lateral view; D, third pereiopod, lateral view; E, fourth pereiopod, lateral view; F, fifth pereiopod, lateral view. page 21 of 31 Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan subdivision longest, slightly longer than sum of other subdivisions, third and fourth subdivisions subequal, second subdivision slightly longer than the third, last subdivision as long as second and third subdivisions combined; chela about 0.3 times as long as carpus, palm and fingers subequal in length. Third pereiopod (Fig. 13D) moderately slender; coxa with strap-like epipod and setobranch; ischium slightly widening distally, about four times as long as distal margin, unarmed ventrally; merus slightly inflated, about 1.5 times as long as ischium; carpus more slender and slightly shorter than merus, 7.5 times as long as distal width, with spiniform seta on distoventral margin; propodus slender, approximately as long as carpus, ventral margin armed with four spiniform setae in addition to distal pair flanking dactylar base; dactylus simple, moderately slender, slightly curved, about 0.5 times as long as propodus. Fourth pereiopod (Fig. 13E) generally similar to third one but slightly more slender; propodus 1.2 times as long as carpus, ventrally armed with three spiniform setae and one distal pair. Fifth pereiopod (Fig. 13F) generally similar to fourth one; coxa without strap-like epipod; carpus slightly shorter than merus; propodus about 1.3 times as long as carpus, ventrally armed with six spiniform setae and one distal pair, bearing 7 rows of microserrulate setae on distoventral margin. Uropod (Fig. 11D) with lateral lobe of protopod broadly triangular; exopod ovate, distolateral margin with small triangular tooth adjacent to spiniform seta, diaeresis sinuous; endopod slightly longer than exopod, ovoid, without specific features. Colour in life: Body largely translucent with pale yellow or pale orange tinge; pleon with faint, buffyellow, transverse bands; antennular and antennal flagella pale yellow; major cheliped whitish with orange-yellow tinge on fingers; remaining appendages colourless or with buff-yellow tinge (Fig. 10). Type locality: Papua New Guinea (present study). Distribution: Papua New Guinea: New Ireland (Ďuriš and Horká 2016; present study); southern China: Xisha Islands (Wang and Sha 2016; Sha et al. 2019 as S. cristatus); probably also in Thailand: Phuket (Banner and Banner 1966, as S. cristatus). Salmoneus alius sp. nov. (Figs. 14–17) urn:lsid:zoobank.org:act:E68C3BB2-FB39-4DA9-95E1FF54979FEB59 Material examined: Holotype: 1 non-ovig. specimen (cl 2.7 mm), MNHN-IU-2019-3495, New Caledonia, Koumac 2019 expedition, sta. HR2, Hienghène, 20°44'59.35"S, 165°16'34.86"E, reef slope, depth 10–34 m, coll. MNHN team, 09.11.2019. Paratypes: 1 ovig. specimen (cl 3.8 mm), FLMNHUF-60000, Solomon Islands, New Georgia, Munda, Sosu Hite Island (informal name), shallow reef flat, less than 1.5 m, under corals and coral rubble, coll. A. Anker, 20.09.2016 (SOL-035); 1 specimen (cl not measured), MNHN-IU-2013-1471, Papua New Guinea, Madang 2012 expedition, sta. PR119, Madang lagoon, northern side of North Kranket Island, 5°11'20.04"S, 145°49'27.03"E, silty reef, depth 1–10 m, coll. A. Anker & Z. Ďuriš, 28.11.2012. Etymology: The new species name is the Latin adjective alius for another or different, referring to yet another new species described in the genus Salmoneus, adding to over 40 species described over the last two decades. Description: Small-sized alpheid shrimp (cl 2.7 mm). Carapace (Fig. 15A, B) with prominent middorsal carina reaching to about posterior margin of eyes, frontal region entirely concealing eyes in dorsal view, distinctly elevated from anterolateral portion of carapace, shoulder-like; rostrum triangular in dorsal view, with subacute tip, reaching to about distal margin of second antennular article, slightly broader than long, rostral carina prominent, continued by mid-dorsal carina on carapace; orbital teeth small, subacute, as long as broad; anterolateral suture present, pterygostomial angle broadly rounded, cardiac notch deep. Pleon (Fig. 15C) scarcely furnished with long fine setae; pleura of first to third pleonites rounded anteroventrally and posteroventrally; fourth and fifth pleura angular posteroventrally; sixth pleuron with subtriangular projection flanking each side of telson, posteroventral suture incomplete. Telson (Fig. 15C, D) sub-rectangular, slightly tapering distally, about four times as long as distal width, proximal margin about 1.6 times as broad as distal margin; dorsal surface with two pairs of spiniform setae located on 0.6 and 0.8 telson length, respectively; posterior margin with broadly U-shaped, central notch furnished with two plumose setae, and two pairs of spiniform setae, mesial pair slightly shorter than plumose setae, much thicker than lateral pair, about 1.5 times as long as lateral one, about five times as long as spiniform setae on dorsal surface. Antennule (Fig. 15A, B) with peduncle relatively stout; first article approximately as long as broad, stylocerite relatively robust, with blunt tip, slightly overreaching distal margin of second antennular article; second article about 1.5 times as broad as long; third article about 1.3 times as long as second article, as long as broad; lateral antennular flagellum biramous, fused portion with two subdivisions, shorter ramus welldeveloped, reaching to about seventh subdivision of page 22 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan longer ramus, with seven or so groups of aesthetascs. Antenna (Fig. 15A, B) with stout basicerite, distoventral margin with subacute tooth, superior margin projecting as small subacute tooth; scaphocerite slightly overreaching mid-length of third antennular article, blade slightly surpassing lateral tooth; carpocerite stout, slightly overreaching second antennular article, flagellum not particularly stout, with second subdivision distinctly longer than others. Third maxilliped (Fig. 17A, B) with coxa bearing strap-like epipod and broadly rounded lateral plate; antepenultimate article slender, about 7.6 times as long as proximal width; penultimate article relatively short, about 0.2 times as long as antepenultimate article; ultimate article about 2.5 times as long as penultimate article, distally armed with two subapical spiniform setae; exopod slender, falling short of reaching distal margin of antepenultimate segment; arthrobranch normally developed. First pereiopods (Fig. 16) very different in size and shape. Major cheliped (Fig. 16A  D) robust, carried flexed under body when not in use; coxa with straplike epipod and setobranch; ischium relatively slender, about 3.3 times as long as proximal width, unarmed ventrally; merus about 1.9 times as long as ischium, slightly widening distally, ventral margin somehow flattened; carpus vase-shaped; chela enlarged, swollen, slightly shorter than combination of basis to carpus; palm robust, swollen, about 1.7 times as long as wide, subcylindrical, slightly flattened dorsally and with shallow depression mid-dorsally, with obsolete ridge on mid-lateral margin and small shallow depression on mid-ventral side of ridge, and with deep complex groove proximally, approximately as long as fingers; fingers with strongly crossing fingertips, no gapping when closed, with 10 (dactylus) or 12 (pollex) evenly distributed teeth slightly enlarging toward distal margin; dactylus without depression proximal part of mesial surface. Minor cheliped (Fig. 16E, F) significantly smaller and weaker than major cheliped; coxa with strap-like epipod and setobranch; ischium slender, about four times as long as mid-width, unarmed ventrally; merus slightly swollen, slightly longer than ischium; carpus slightly shorter than merus, widening distally; chela simple, with palm approximately as long as fingers; cutting edge of fingers unarmed. Second pereiopod (Fig. 17C) moderately long, slender; coxa with strap-like epipod and setobranch; ischium slender, about 6.5 times as long as wide, unarmed ventrally; merus slender, slightly longer than ischium; carpus slender, 1.3 times as long as merus, with five subdivisions, proximal subdivision longest, slightly longer than sum of other subdivisions, third and fourth subdivisions subequal, second subdivision slightly longer than third one, distal subdivision as long as second and third subdivisions combined; chela about 0.4 times as long as carpus, palm and fingers subequal in length. Third pereiopod (Fig. 17D) moderately slender, coxa with strap-like epipod and setobranch; ischium slightly widening distally, about three times as long as distal margin, with two strong spiniform setae on ventrolateral surface; merus slightly inflated, about 1.7 times as long as ischium; carpus slenderer and shorter than merus, 5.3 times as long as distal width, with spiniform seta on distoventral margin; propodus slender, approximately as long as carpus, with ventral margin armed with four 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. 17E) generally similar to the third, more slender somewhat; propodus 1.1 times as long as carpus, ventral margin armed with three spiniform setae and one pair distally. Fifth pereiopod (Fig. 17F) generally similar to fourth; coxa without strap-like epipod; ischium unarmed ventrally; carpus slightly longer than merus; propodus about 1.3 times as long as carpus, ventral margin armed with five spiniform setae and one pair distally, bearing seven rows of microserrulate setae on distoventral margin; dactylus conical, somewhat blunt distally (probably due to usage). Uropod with lateral lobe of protopod broadly triangular; exopod ovate, distolateral margin with small triangular tooth adjacent to spiniform seta; diaeresis sinuous, with blunt lobe mesial to spiniform seta; endopod ovoid, without specific features. Colour in life: Body largely translucent with yellow tinge; pleon with faint, yellow, transverse bands; antennular and antennal flagella pale yellow; major cheliped whitish with buff tinge on fingers; remaining appendages colourless; developing ovaries and eggs orange (Fig. 14). Type locality: New Caledonia (holotype); additional type material from Papua New Guinea and Solomon Islands (present study). Distribution: Presently known from the northeastern coast of New Caledonia, Papua New Guinea (Kavieng), and the Solomon Islands (New Georgia). DISCUSSION Coutière (1897a) briefly described Salmoneus cristatus (as Jousseaumea cristata) based on an unspecified number of specimens collected in Djibouti, with some remarks on the species’ colour pattern. Banner and Banner (1981: p. 51, table 2) stated page 23 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 14. Salmoneus alius sp. nov., holotype, non-ovigerous specimen (cl 2.7 mm) from New Caledonia (MNHN-IU-2019-3495), shrimp in life in dorsal view (A) lateral view (B); paratype, ovigerous specimen (cl 3.8 mm) from the Solomon Islands (FLMNH-UF-60000), shrimp in life in lateral view (C). [photographs A, B by ZĎ; and C by AA]. page 24 of 31Zoological Studies 62:53 (2023) © 2023 Academia Sinica, Taiwan Fig. 15. Salmoneus alius sp. nov., holotype, non-ovigerous specimen (cl 2.7 mm) from New Caledonia (MNHN-IU-2019-3495): A, anterior region of carapace and frontal appendages, lateral view; B, same, dorsal view; C, posterior pleonites, telson and left uropod, lateral view; D, telson, dorsal view. page 25 of 31Zoological Studies 62:53 (2023)