Leptalpheus lirai Caripe & Pereda & Anker 2021, sp. nov.
Creators: name: Caripe, Jonathan Vera
name: Pereda, Luisana
name: Anker, Arthur
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Leptalpheus
Leptalpheus lirai

description: Leptalpheus lirai sp. nov.
(Figs. 1–3)
Type material. Holotype: female (cl 10.1 mm), MBUCV-5558, Venezuela, Sucre, Gulf of Santa Fe, Bahía Petare, 10°19’12.5394”N – 64°22’38.2255”W, shallow subtidal flat near seagrass beds and mangrove trees, depth 1.0 m, in burrow, suction pump, leg. L. Pereda, 3 April 2008.
Description. Frontal margin of carapace dorsally nearly straight, without rostral projection, separated from anterolateral margin of carapace by shallow v-shaped notch (Fig. 2A); pterygostomial angle rounded, not anteriorly produced; branchiostegial margin with wide lip; posterior margin with deep cardiac notch (Figs. 1, 2C). Pleon with all pleomeres rounded; sixth pleomere with subtriangular articulated flap, distally rounded (Fig. 1). Telson (Fig. 2F) widest in proximal third, distinctly tapering distally; dorsal surface with two pairs of stout spiniform setae situated at some distance from lateral margin; posterior margin broadly rounded, with two pairs of spiniform setae at each posterolateral angle, lateral spiniform setae much more slender and shorter than mesial spiniform setae; posterior margin between mesial spiniform setae with numerous long plumose setae.
Eyes dorsally and laterally completely concealed by carapace (Fig. 2A, B); eyestalks with anteromesial margin somewhat produced anteriorly, rounded.
Antennular peduncles (Fig. 2A, B) stout, dorsoventrally depressed; stylocerite appressed against first article, not exceeding distal margin of first article, distal margin rounded; ventromesial carina of first article with simple, anteriorly pointing tooth (Fig. 2D); second article elongate, 2.7 times longer than maximal width; lateral flagellum with short secondary ramus furnished with aesthetascs. Antenna (Fig. 2A, B) with basicerite large, stout, ending in subacute distoventral tooth; scaphocerite elongate, ovate, its distolateral tooth greatly reduced to small blunt lobe; carpocerite stout, reaching far beyond scaphocerite and slightly beyond end of antennular peduncle; flagellum robust, without tooth-like processes.
Mouthparts (mandible, maxillule, maxilla, first and second maxillipeds) typical for genus in external view. Third maxilliped (Fig. 1G) with lateral plate on coxa strongly projecting, distally subacute; ultimate article shorter than antepenultimate article, with rings of thick serrulate setae and blunt tip, without spiniform setae; arthrobranch well developed (omitted in Fig. 1G).
Chelipeds strongly asymmetrical in shape and unequal in size (Figs. 1, 3), carried folded when not in use. Major cheliped (Fig. 3A–D) slender proximally, but with enlarged, stout chela; ischium relatively short, with oblique distal margin, merus slender, gently curved, with convex dorsal surface and smooth lateral and dorsal margins, ventrally strongly depressed to accommodate chela; carpus very short, somewhat square-shaped; chela enlarged, elongate, swollen, with palm excavated ventrolaterally; fingers about 0.7 palm length, somewhat twisted, slightly gaping when closed, crossing distally; pollex with blunt latero-proximal projection and simple tip, latter strongly curved towards dactylus; cutting edge of pollex with very broad tooth in form of subrectangular elevation at about midlength; dactylus dorsally convex, as long as pollex, with distinct proximal elevation adjacent to adhesive disk, with strongly curved, truncate tip; cutting edge of dactylus with two widely spaced, bulging, subrectangular teeth at about 0.4 and 0.7 of dactylar length, respectively, and two much smaller proximal teeth; adhesive disks well developed. Minor cheliped (Fig. 3E–G) much shorter and more slender than major cheliped; ischium short, unarmed mesially; merus elongate, slender, about seven times as long as maximal height, about three times as long as ischium, slightly longer than palm, nearly straight, ventrally depressed, with smooth surface; carpus short, cup-shaped; palm slightly inflated, mesially flattened, smooth; fingers longer than palm, with distally crossing tips; cutting edge of pollex with about 12 small, somewhat spaced, recurrent (backwards pointing) teeth ranging from base to about 0.6 of pollex length; cutting edge of dactylus with six teeth, latter generally similar to those of pollex, more widely spaced, located between approximately 0.3 and 0.6 of dactylar length.
Second pereiopod (Fig. 2H, I) moderately slender; merus distinctly longer than ischium; carpus with five subarticles, proximal longest, middle three almost equally short, distal-most about 0.6 length of proximal; chela about as long as distal-most carpal subarticle. Third pereiopod (Fig. 2J) relatively stout, laterally compressed; ischium with one small spiniform seta on ventrolateral surface; merus about 4.6 times as long as maximal width; carpus stout, about 0.3 length of merus, with one long stout spiniform seta on distoventral margin; propodus slightly longer than carpus, with three robust spiniform setae on ventral margin and one distoventral pair of spiniform setae adjacent to dactylus (lateral one broken in Fig. 2J); dactylus more than half-length of propodus, simple, conical, slightly curved, distally acute. Fourth pereiopod (Fig. 2K) similar to third pereiopod, but with different proportions of articles; ischium with one small spiniform seta on ventrolateral surface; merus slightly stouter, 4.2 times as long as maximal width; carpus more slender, 0.4 length of merus, with one long stout spiniform seta on distoventral margin; propodus distinctly longer and more slender than carpus, with three robust spiniform setae on ventral margin and one distoventral pair of spiniform setae adjacent to dactylus; dactylus distinctly less than half-length of propodus, simple, conical, slightly curved, distally subacute. Fifth pereiopod (Fig. 2L) distinctly more slender than third and fourth pereiopods, not compressed; ischium 0.4 length of merus, unarmed; merus no inflated, as wide as ischium, about 5.7 times as long as wide; carpus about 0.8 length of merus; propodus slightly longer than carpus, with welldeveloped grooming brush on distolateral surface, composed of at least seven rows of serrulate setae; dactylus similar to that of fourth pereiopod, 0.3 times as long as propodus.
Uropods (Fig. 2E) distinctly exceeding telson; lateral lobe of protopod distally with two small blunt projections; endopod longer than exopod, latter posteriorly truncate; diaeresis with lateral portion almost straight, mesial angle marked by strong, projecting, subtriangular tooth.
Colour in life. Not recorded.
Type locality. Bahía Petare, Gulf of Santa Fe, Sucre, Venezuela.
Distribution. Only known from the type locality in Venezuela.
Etymology. The species is named after our good friend and colleague, Carlos Lira Gómez (Universidad de Oriente, Nueva Esparta, Venezuela), a well-known taxonomist of decapod crustaceans.
Ecology. The single specimen of L. lirai sp. nov. was collected from a burrow of an unknown host made in soft sediments ranging from fine sand to sand-mud, at a depth of about 1 m, very close to seagrass beds and mangroves.
Remarks. Leptalpheus lirai sp. nov. belongs to an informal (and possibly non-monophyletic) group of currently nine species within Leptalpheus, which possess well-developed adhesive disks on the major chela. According to Anker & Vera-Caripe (2016), this group includes the following species: L. axianassae Dworschak & Coelho, 1999 and L. pereirai Anker & Vera-Caripe, 2016 in the western Atlantic; L. canterakintzi Anker & Lazarus, 2015, L. azuero Anker, 2011 and L. corderoae Salgado-Barragán, Ayón-Parente & Hendrickx, 2014 in the eastern Pacific Ocean; and L. pacificus Banner & Banner, 1974, L. denticulatus Anker & Marin, 2009, and L. dworschaki Anker & Marin, 2009 in the Indo-West Pacific (Dworschak & Coelho 1999; Anker & Marin 2009; Anker 2011; Salgado-Barragán et al. 2014; Anker & Lazarus 2015; Anker & Vera-Caripe 2016).
The new species can be separated from all afore-mentioned species of Leptalpheus by three characteristics. In L. lirai sp. nov., the frontal margin of the carapace is almost straight (Fig. 2A), compared to the more projecting anterior margin, which can be rounded or sub-triangular, blunt or sharp, distally, in the remaining species (cf. Dworschak & Coelho 1999; Anker & Marin 2009; Anker 2011; Salgado-Barragán et al. 2014; Anker & Lazarus 2015; Anker & Vera-Caripe 2016). The presence of robust and elongate spiniform setae on the ventral (flexor) margin of the propodi of the third and fourth pereiopods is another distinguishing feature of L. lirai sp. nov. (Fig. 2J, K); these spiniform setae are more slender and shorter in the other species (cf. Dworschak & Coelho 1999; Anker & Marin 2009; Anker, 2011; Salgado-Barragán et al. 2014; Anker & Lazarus 2015; Anker & Vera-Caripe 2016). Noteworthy, in the general robustness of the walking legs, including the unusually robust spiniform setae on their propodi, L. lirai sp. nov. resembles the two species of the related genus Fenneralpheus (cf. Anker 2011: figs. 20J, 26E). Finally, L. lirai sp. nov. possesses a unique dentition on the major chela fingers (Fig. 3C), which differs from the finger armature of the other related species (cf. Dworschak & Coelho 1999: figs. 18, 19 for L. axianassae; Anker & Vera-Caripe 2016: fig. 2c, d for L. pereirai; Anker & Lazarus 2015: fig. 6B for L. canterakintzi; Anker 2011: fig. 6C, D for L. azuero; Salgado-Barragán et al. 2014: fig. 4A, C for L. corderoae; Banner & Banner 1974: fig. 1F, G for L. pacificus; Anker & Marin 2009: figs. 3c, d; 7c, d for L. dworschaki and L. denticulatus, respectively).
In addition, L. lirai sp. nov. can be separated from its two morphologically closest western Atlantic congeners, viz. L. axianassae and L. pereirai, by the presence of a spiniform seta on the ischia of the third and fourth pereiopods (Fig. 2J, K) (absent in L. axianassae and L. pereirai); the antennal scaphocerite with a greatly reduced distolateral tooth (vs. with a well-developed distolateral tooth in L. axianassae and L. pereirai); and the lateral lobe of the uropodal protopod ending in two blunt projections (Fig. 2E) (vs. ending in two acute projections in L. axianassae and L. pereirai) (cf. Dworschak & Coelho 1999; Anker & Lazarus 2015; Anker & Vera-Caripe 2016). The new species also differs specifically from L. axianassae by the ventromesial carina of the first article of the antennular peduncle with a simple tooth (Fig. 2D), as in L. pereirai (vs. with a distally bifid tooth in L. axianassae) (Dworschak & Coelho 1999; Anker & Vera-Caripe 2016).
Leptalpheus lirai sp. nov. is easily distinguishable from the most closely related eastern Pacific species, i.e. L. azuero, L. canterakintzi and L. corderoae, by the presence of a simple tooth on the ventromesial carina of the first article of the antennular peduncle (Fig. 2D) (vs. with a distally bifid tooth in L. azuero, L. canterakintzi and L. corderoae); the antennular stylocerite not reaching the distal margin of the first article of the antennular peduncle and distally blunt (Fig. 2A) (vs. also not exceeding the distal margin of the first article, but distally acute in L. corderoae, and exceeding the distal margin of the first article and distally acute in L. canterakintzi and L. azuero) (cf. Anker & Lazarus 2015; Anker 2011; Salgado-Barragán et al. 2014).
The new species from Venezuela shows less affinities with the three Indo-West Pacific species of Leptalpheus characterised by the presence of suction disks on the major chela, viz. L. pacificus, L. denticulatus and L. dworschaki. For instance, L. lirai sp. nov. can be readily separated from all of them by the very different dentition of the major chela (Fig. 3) (cf. Banner & Banner 1974; Anker & Marin 2009); the proportion of the minor cheliped merus (three times as long as ischium in the new species vs. about twice or slightly more than twice as long as ischium in L. denticulatus and L. pacificus, or more than three times the length of the ischium in L. dworschaki); the antennal scaphocerite with a greatly reduced tooth (vs. with a well-developed one in the three Indo-West Pacific species); and the presence of a spiniform seta on the ischium of the third and fourth pereiopods (absent in the three Indo-West Pacific species). Finally, L. lirai sp. nov. can be easily distinguished from both species of Fenneralpheus by the very different dentition on the major chela fingers (cf. Felder & Manning 1986; Anker 2011).
description: Published as part of Caripe, Jonathan Vera, Pereda, Luisana & Anker, Arthur, 2021, A new species and two new records of symbiotic infaunal alpheid shrimps from the genera Leptalpheus Williams, 1965 and Fenneralpheus Felder & Manning 1986 (Decapoda: Caridea) from Venezuela, pp. 177-184 in Zootaxa 5061 (1) on pages 178-182, DOI: 10.11646/zootaxa.5061.1.10, http://zenodo.org/record/5642138