Leptalpheus ankeri, Scioli & Robles & Felder, 2024

Scioli, Justin A., Robles, Rafael & Felder, Darryl L., 2024, New species and records of the symbiotic shrimp genus Leptalpheus Williams, 1965, with notes on Fenneralpheus Felder & Manning, 1986, and preliminary molecular analysis of phylogenetic relationships (Crustacea: Decapoda: Alpheidae), Zootaxa 5466 (1), pp. 1-72 : 13-30

publication ID

https://doi.org/ 10.11646/zootaxa.5466.1.1

publication LSID

lsid:zoobank.org:pub:B43F7FDA-5E3B-4153-A991-E2A96E582A3B

persistent identifier

https://treatment.plazi.org/id/03DF87CE-FFB1-FFB4-8CC4-FD564E98EA3A

treatment provided by

Plazi

scientific name

Leptalpheus ankeri
status

sp. nov.

Leptalpheus ankeri n. sp.

( Figs. 3–16 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 View FIGURE 15 View FIGURE 16 )

Leptalpheus sp. — Felder & Manning, 1997: 329.— Felder & Staton 2000: 179.

Leptalpheus sp. 1 aff. forceps View in CoL .— Anker et al., 2006b: table 1.

Leptalpheus sp. 2 aff. forceps .— Anker et al., 2006b: table 1.

Leptalpheus sp. 3 .— Robles, 2005: chapter 3, table 1.

Leptalpheus sp. 4 .— Robles, 2005: chapter 3, table 1.

Type material. Holotype: female (cl 8.3 mm) [major cheliped morphotype A], ULLZ 18502 View Materials [ USNM 1705353 View Materials ], Panama, Caribbean coast, Bocas del Toro, Isla Colón, Boca del Drago , at mouth of small creek south of Playa de Estrellas , 0–0.5 m, coll. J.A. Scioli, 21.05.2018 . Paratypes: 1 ovigerous female (cl 8.3 mm) [major cheliped morphotype A], ULLZ 18503 View Materials [ USNM 1705354 View Materials ], same locality as holotype, with Lepidophthalmus richardi (host catalog no. ULLZ 18513 View Materials [ USNM 1706528 View Materials ]), coll. J.A. Scioli, 03.07.2018; 1 female (cl 8.6 mm) [major cheliped morphotype A], UF 51703 , same locality as previous, from burrow of L. richardi , coll. M. Leray & P.P.G. Pachelle, 05.04.2019 ; 1 ovigerous female (cl 7.0 mm) [major cheliped morphotype A], UF 51704 , same collection locality as previous, from burrow of L. richardi , coll. M. Leray & P.P.G. Pachelle, 05.04.2019 ; 1 ovigerous female (cl 11.5 mm) [major cheliped morphotype A], UF 51714 , same collection locality as previous, from burrow of L. richardi , coll. M. Leray & P.P.G. Pachelle, 05.04.2019 .

Additional material. Panama: 1 ovigerous female (cl 8.2 mm) [major cheliped missing], ULLZ 18501 View Materials [ USNM 1706526 View Materials ], same collection locality as holotype, coll. J.A. Scioli, 11.05.2018 ; 1 female (cl 10.1 mm) [major cheliped morphotype B], ULLZ 18504 View Materials [ USNM 1706527 View Materials ], same collection locality as previous, coll. J.A. Scioli, 07.05.2018 ; 1 female (cl 11.4 mm) [major cheliped morphotype B], UF 51715 , same collection locality as previous, from burrow of L. richardi , coll. M. Leray & P.P.G. Pachelle, 05.04.2019 . USA: 1 female (cl 7.0 mm) [major cheliped morphotype A], ULLZ 10312 View Materials [ USNM 1544879 View Materials ], Florida, Ft. Pierce, Dynamite Point near Inlet State Park , coll. D.L. Felder & K. Strasser, 03.06.1997 ; 1 male (cl 4.8 mm) [major cheliped morphotype A], 4 ovigerous females (cl 5.1–6.2 mm) [major chelipeds missing], ULLZ 18290 View Materials [ USNM 1706525 View Materials ], Florida, Ft. Pierce, coll. D.L. Felder, 01.08.1987 ; 1 male (cl 5.2 mm) [major cheliped morphotype A], ULLZ 18281 View Materials [ USNM 1706517 View Materials ], Florida, Ft. Pierce, coll. D.L. Felder, 15.08.1987 ; 1 male (cl 5.1 mm) [major cheliped morphotype A], ULLZ 18709 View Materials [ USNM 1706535 View Materials ], Florida, Ft. Pierce, Indian River Lagoon , Coon Island , coll. R. B. Manning & D.L. Felder, 18.07.1985 ; 1 ovigerous female (cl 5.5 mm) [major cheliped morphotype B], ULLZ 18286 View Materials [ USNM 1706521 View Materials ], Florida, Port St. Lucie , Jensen Beach, from burrow of Neocallichirus grandimana , coll. D.L. Felder, 08.01.1993 ; 1 female (cl 3.4 mm) [major cheliped missing], ULLZ 6050 View Materials [ USNM 1541294 View Materials ], Florida, Ft. Pierce, Coon Island , tidal channel off inlet, coll. D.L. Felder, 26.07.2001 ; 1 male (cl 5.9 mm) [major cheliped morphotype B], ULLZ 18707 View Materials [ USNM 1706533 View Materials ], Florida, Ft. Pierce, coll. R.B. Manning & D.L. Felder, 14.02.1990 . Mexico: 2 males (cl 9.0, 9.1 mm) [major cheliped morphotype B], 4 ovigerous females (cl 8.4–9.8 mm) [major chelipeds missing], ULLZ 18287 View Materials [ USNM 1706522 View Materials ], Campeche, Nuevo Campechito, from burrows of Lepidophthalmus sp. , coll. D.L. Felder, J. Staton, et al., 27.03.1991 ; 1 male (cl 4.2 mm) [major cheliped morphotype B], ULLZ 5184 View Materials [ USNM 1540793 View Materials ], same locality as previous, from burrows of Lepidophthalmus manningi , coll. D.L. Felder & R. Robles, 07.07.2001 ; 1 ovigerous female (cl 6.1 mm) [major cheliped morphotype B], ULLZ 18288 View Materials [ USNM 1706523 View Materials ], Tamaulipas, Barra del Tordo, Río Carrizal , from burrows of Lepidophthalmus louisianensis , coll. D.L. Felder, 14.08.1987 ; 1 male (cl 6.3 mm) [major cheliped morphotype B], ULLZ 18289 View Materials [ USNM 1706524 View Materials ], Tamaulipas, Barra del Tordo , coll. D.L. Felder, 25.03.1982 . Belize: 1 male (cl 6.4 mm) [major cheliped morphotype B], 1 ovigerous female (cl 8.1 mm) [major cheliped missing], ULLZ 11171 View Materials [ USNM 1545578 View Materials ], Stann Creek, Twin Cays, coll. D.L. Felder et al., 20.02.2009 ; 1 female (cl 7.2 mm) [major cheliped morphotype B], ULLZ 18708 View Materials [ USNM 1706534 View Materials ], Stann Creek, Dangriga , in front of Pelican hotel, coll. D.L. Felder, 18.04.1983 . Venezuela: 1 ovigerous female (cl 6.8 mm) [major cheliped morphotype A], ULLZ 18282 View Materials [ USNM 1706518 View Materials ] , Isla la Tortuga, coll. C. Lira, collection date not recorded. Jamaica: 1 male (cl 8.1 mm) [major cheliped morphotype B], ULLZ 5604 View Materials [ USNM 1541049 View Materials ], near Lucea, Mosquito Cove , from burrows of Lepidophthalmus jamaicense , coll. D.L. Felder & R. Robles, 14.05.2003 .

Description. Frontal margin of carapace broadly rounded, without rostral projection or orbital crests ( Fig. 3a, b View FIGURE 3 ). Carapace glabrous; branchiostegal margin with narrow folded lip; lip broadest posteriorly and gradually tapering in breadth anteriorly; pterygostomian angle rounded, not strongly projecting anteriorly. Telson 2–3 times as long as basal breadth, gradually tapering in breadth throughout length; distal margin arcuate, 0.4–0.5 times as broad as basal margin; dorsal surface bearing two pairs of spiniform setae; anterior pair inserted at 0.3–0.4 length of telson from base; posterior pair inserted at 0.55–0.7 of length of telson from base; posterolateral margins with two pairs of spiniform setae; mesial pair 4–5 times length of lateral pair ( Fig. 3d View FIGURE 3 ).

Antennular peduncles moderately stout; stylocerite somewhat appressed against first article, with obtuse distal margin not reaching distal margin of first antennular article; ventromesial carina bearing subacute, anteriorly directed ventral tooth; second antennular article 2–3 times as long as broad; secondary ramus of lateral flagellum furnished with aesthetascs beginning on article 4–6 ( Fig. 3a–c View FIGURE 3 ).Antennal peduncles subequal in length to antennular peduncles; basicerite bearing broad, subacute ventrolateral tooth, tip of latter distally reaching distal margin of stylocerite; scaphocerite broad, oval-shaped, 2–3 times as long as widest breadth, bearing minute, subacute distolateral tooth; carpocerite broad, 2.5–4 times as long as widest breadth, distally overreaching scaphocerite ( Fig. 3a, b View FIGURE 3 ).

Mouthparts somewhat typical for genus. Mandible with 2-segmented palp; molar process small, bearing rows of minute, stiff setae; incisor process bearing 5 or 6 teeth ( Fig. 3f View FIGURE 3 ). Maxillule with bilobed palp ( Fig. 3g View FIGURE 3 ). Maxilla with dorsal endite bearing deep groove; scaphognathite somewhat broad, palp present ( Fig. 3h View FIGURE 3 ). First maxilliped with small palp; exopod with expanded caridean lobe; epipod bilobed ( Fig. 3i View FIGURE 3 ). Second maxilliped with broad, roughly oval-shaped epipod ( Fig. 3j View FIGURE 3 ). Third maxilliped with well-developed arthrobranch; lateral plate slender, elongate, distally overreaching half-length of antepenultimate article, with subacute tip; exopod long, overreaching antepenultimate article; ultimate article shorter than antepenultimate article, bearing transverse rows of setae on mesial face, with blunt tip ( Fig. 3k View FIGURE 3 ).

Major cheliped slender; ischium bearing subacute subtriangular projection on ventromesial margin; merus slender, 4–6 times as long as maximum breadth, with ventral margin concave to accommodate chela when folded; ventrolateral, ventromesial and dorsal margins of merus all lined with minute tubercles throughout length; carpus short, cup-shaped, with 2 subtriangular projections on distoventral margins; chela slender, tapering in breadth distally, bearing numerous minute tubercles throughout ventral half; adhesive disks absent; fingers 0.2–0.3 palm length; dactylus curving ventrally in distal half, bearing small, obtuse proximal tooth, a deep, large, plunger-like medial tooth and 3–8 minute, obtuse subapical teeth; pollex distinctly overreaching dactylus, bearing proximal, rounded tooth, medial large, subrectangular projection, and 2–5 rounded, minute subapical teeth, with tip strongly curving laterally ( Fig. 5 View FIGURE 5 ).

Minor cheliped distinctly smaller than major cheliped; ischium unarmed; merus relatively slender, with concave ventral face to accommodate chela when folded; ventrolateral, ventromesial and dorsal margins smooth; carpus short, cup-shaped; chela slender, 4–7 times as long as maximum height; fingers subequal in length to palm; ventral margin slightly concave at base of fingers; dactylus and pollex both with raised cutting margins bearing minute, subacute medial projections; tips distally crossing when closed ( Fig. 4a, b View FIGURE 4 ).

Second pereopod slender, with merus longer than ischium; carpus subdivided into five articles, with article ratio approximately 10: 2: 3: 2: 5; fingers of chela subequal in length to palm, bearing sparse setal tufts ( Fig. 4c View FIGURE 4 ). Third pereopod laterally compressed; ischium unarmed; merus unarmed, 3–4.5 times as long as maximum height; carpus 0.35–0.55 length of merus, bearing distoventral spiniform seta, with distodorsal margin projecting over carpo-propodal articulation; propodus bearing three spiniform setae along ventral margin; dactylus tapering in breadth to acute, simple tip ( Fig. 4d View FIGURE 4 ). Fourth pereopod similar to third, but slightly slenderer ( Fig. 4e View FIGURE 4 ). Fifth pereopod slender, not compressed; ischium short, unarmed; merus slender, 4–6 times as long as maximum height; carpus slender; propodus bearing 4–9 transverse rows of grooming setae on lateral face and minute spiniform seta in middle of ventromesial margin; dactylus simple, with acute tip ( Fig. 4f, g View FIGURE 4 ).

Male second pleopod with long, slender appendix masculina, latter 1.5–2 length of appendix interna, bearing apical setae ( Fig. 4h View FIGURE 4 ). Uropod with bilobed protopod; lateral lobe of protopod with shallow concavity on distal margin; uropodal exopod with truncate distal margin; uropodal endopod with or without distal appendix composed of 1–5 articles ( Fig. 3e View FIGURE 3 ).

Variation. Two distinct major cheliped morphotypes were present among specimens of L. ankeri n. sp. Some specimens exhibited the armature of the dactylus and pollex described above (major cheliped morphotype A) whereas others exhibited a form with dactylus and pollex both curving ventrolaterally throughout length, each bearing 8–15 small, rounded teeth on raised cutting margins (major cheliped morphotype B) ( Figs. 8 View FIGURE 8 , 13e, f View FIGURE 13 ,).

Some, but not all, specimens of L. ankeri n. sp. have caudal appendices on the distal margins of the uropodal endopods. These appendices were either small and unsegmented ( Figs. 3e View FIGURE 3 , 6k View FIGURE 6 ), longer and composed of 2–5 articles ( Fig. 6l View FIGURE 6 ), or completely absent ( Figs. 10a, b View FIGURE 10 , 14a, b View FIGURE 14 ). Specimens with caudal appendices were generally larger-bodied (cl 7.0– 11.5 mm) than those without them (cl 3.4–10.1 mm).

Color in life. Semitransparent with yellowish tinge; yellow coloration strongest on carapace, antennae, antennules, telson, and uropods, subtle to absent on pereopods; body speckled throughout with red chromatophores, most densely on anterior margins of abdominal somites where they form transverse bands; major cheliped hyaline-white with sparse chromatophores; ovaries and eggs yellow-green ( Figs. 15 View FIGURE 15 , 16 View FIGURE 16 ). Specimens with expanded chromatophores appear generally reddish except for distal portions of the pereopods ( Figs. 15e–g View FIGURE 15 , 16g, h View FIGURE 16 ).

Etymology. Named in honor of our colleague Arthur Anker (Universidade Federal de Pelotas, Rio Grande do Sul, Brazil) in recognition of his numerous contributions to the biology, taxonomy, and evolution of snapping shrimps, including Leptalpheus .

Type locality. Isla Colón, Bocas del Toro , Caribbean coast, Panama.

Distribution. Atlantic coast of USA, Gulf of Mexico, and Caribbean Sea: Atlantic coast of Florida, USA ( Felder & Manning 1997; present study); Gulf coasts of Tamaulipas, Tabasco, and Campeche, Mexico ( Felder & Staton 2000; present study); Caribbean coasts of Panama (present study), Venezuela (present study), Belize ( Felder & Manning 1997; present study), and Jamaica (present study).

Ecology. Obligate burrow cohabitant of axiidean ghost shrimps in the genera Lepidophthalmus and Neocallichirus : associated with Lepidophthalmus richardi Felder & Manning, 1997 in Panama and Belize, Lepidophthalmus jamaicense ( Schmitt, 1935) in Jamaica, Lepidophthalmus manningi Felder & Staton, 2000 and Lepidophthalmus louisianensis ( Schmitt, 1935) in Mexico, and Neocallichirus grandimana ( Gibbes, 1850) in Florida.

Remarks. Leptalpheus ankeri n. sp. has been previously reported as an undescribed species for its associations with the ghost shrimps L. richardi and L. manningi ( Felder & Manning 1997; Felder & Staton 2000). The specimens referred to in those studies are included among the material listed above.

This species is remarkable for its two distinct major cheliped morphotypes. Previous listings of undescribed species of Leptalpheus considered these two morphotypes to constitute different species ( Robles 2005; Anker et al. 2006b). However, none of the three genetic markers used in our analyses distinguished these two morphotypes, and genetic distances between specimens of the same morphotype overlapped with distances between morphotypes, strongly indicating the two forms represent a single, polymorphic species. To ensure these results were not the result of DNA contamination or other error, we re-extracted DNA and re-sequenced genetic markers from specimens of both morphotypes, which resulted in the same sequence data. The morphology of the major chelipeds of all specimens of L. ankeri n. sp. listed above corresponded to one of these two morphotypes, with no intermediate forms being detected. No other morphological characters corresponded with these two cheliped morphotypes (compare morphotype A, Figs. 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 , 9–11 View FIGURE 9 View FIGURE 10 View FIGURE 11 vs. morphotype B, Figs. 6–8 View FIGURE 6 View FIGURE 7 View FIGURE 8 , 12–14 View FIGURE 12 View FIGURE 13 View FIGURE 14 ). This is not a case of sexual dimorphism, as both males and females of each morphotype were present. Furthermore, these two morphotypes do not appear to represent developmental stages, as body sizes of specimens of each morphotype were overlapping (morphotype A ranged from cl 4.8–11.5 mm; morphotype B ranged from cl 4.2–10.1 mm). Although we find this outcome to be unlikely, it is possible that later studies will uncover evidence separating the two morphotypes into different species, and for this reason we have restricted the type series of L. ankeri n. sp. to specimens of morphotype A.

The genetic data provided herein for L. ankeri n. sp. were all sequenced from specimens from the Caribbean Sea ( Belize and Panama). However, we found no major morphological differences between specimens from these localities and those collected in the Atlantic coast of Florida or the Gulf of Mexico (compare L. ankeri n. sp. from Panama, Figs. 3–8 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 vs. L. ankeri from Ft. Pierce, Florida, Figs. 9–14 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 ). We did find that specimens from the Caribbean Sea were notably larger than those collected on the Atlantic coast of Florida (cl 6.4–11.5 mm vs. 3.4–7.0 mm).

Leptalpheus ankeri n. sp. is a member of the Leptalpheus forceps species group. It can be distinguished from species of Leptalpheus outside this group and members of related genera by the absence of an adhesive disk on the major cheliped, the strongly dorsally produced lateral plate on the third maxilliped (reaching near or beyond the midpoint of the antepenultimate article of the endopod), and the subtriangular projection on the ventromesial margin of the ischium of the major cheliped. Six other species exhibit this combination of characters: L. forceps , L. marginalis , L. melendezensis , L. mexicanus and two additional new species described below.

Leptalpheus forceps can be distinguished from both morphotypes of L. ankeri n. sp. based on the armature of the fingers of the major cheliped (bearing subacute teeth in proximal half and gaping in distal half in L. forceps ). Furthermore, L. forceps differs from L. ankeri n. sp. in the proportions of the second antennular article (2–3 times as long as broad in L. ankeri n. sp. vs. 3.5–6 times as long as broad in L. forceps ).

Leptalpheus marginalis , which is known from Colombia and Brazil, has a morphologically very similar major cheliped to L. ankeri n. sp. morphotype B. It can readily be distinguished from the new species by the presence of dorsal crests on the frontal margin of the carapace and dorsal processes on the proximal articles of the antennal flagella, both of which are absent in all specimens of L. ankeri n. sp. Rosário et al. (2020) reported some specimens of L. marginalis from Brazil lacking these dorsal crests, however these specimens still exhibited the dorsal processes on the proximal articles of the antennal flagella (see Rosário et al. 2020: fig. 9C).

The eastern Pacific L. melendezensis differs from both morphotypes of L. ankeri n. sp. in the armature of the fingers of the major cheliped (with two large, proximal subtriangular teeth on the pollex and a single, deep proximal tooth on the dactylus). In addition, the cutting margins of the fingers of the minor cheliped bear 4 or 5 small teeth in L. melendezensis , whereas they bear only a single subacute projection in L. ankeri n. sp. Lastly, the propodi of the third and fourth pereopods bear 2 spiniform setae in L. melendezensis (vs. 3 in L. ankeri n. sp.).

Leptalpheus mexicanus , also known from the eastern Pacific, can be easily distinguished from both morphotypes of L. ankeri n. sp. by its unique major cheliped, which is extremely curved and distally gaping (see Ríos & Carvacho 1983: fig. 2).

For morphological separation of L. ankeri n. sp. from two other related species described herein, see remarks below.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Alpheidae

Genus

Leptalpheus

Loc

Leptalpheus ankeri

Scioli, Justin A., Robles, Rafael & Felder, Darryl L. 2024
2024
Loc

Leptalpheus sp.

Felder, D. L. & Staton, J. L. 2000: 179
Felder, D. L. & Manning, R. B. 1997: 329
1997
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