Leptalpheus azuero Anker, 2011

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 : 37-39

Leptalpheus azuero Anker, 2011

( Fig. 21a–e )

Leptalpheus azuero Anker, 2011: 9 ; figs 5–7.— Anker & Lazarus, 2015: 116.

Leptalpheus canterakintzi Anker & Lazarus, 2015: 122 , figs. 5–7. [New synonymy]

Leptalpheus sp. 9 .— Anker et al., 2006b: table 1.

“ Leptalpheus ” nov. sp. B.— Felder et al., 2003: table 3.

“ Leptalpheus ” sp. 6.— Robles, 2005: chapter 3, table 1.

Type material examined. Holotype: female (cl 2.8 mm), MNHN-IU-2011-5239, Panama, Pacific coast, Chitré, Playa El Agallito, mudflat near mangroves, collected by yabby pump, 0.2–0.5 m at low tide, coll. A. Anker & J.A. Vera Caripe, 08.11.2006 . Paratypes: 1 male (cl 3.7 mm), 3 females (cl 2.8–2.9 mm), MNHN-IU-2011-5240, same locality as previous, coll. A. Anker & J.A. Vera Caripe, 08.11.2006 .

Additional material examined. Nicaragua: 1 ovigerous female (cl 4.7 mm), ULLZ 11823 [ USNM 1545912 ], Pacific coast, León, Las Peñitas, coll. D.L. Felder & R. Robles, 14.08.2001; 1 male (cl 6.0 mm) , 1 ovigerous female (cl 6.4 mm), ULLZ 5917 [ USNM 1541195 ], Pacific coast, Chinandega, Estero Aserradores, muddy sand beach, with Axianassa canalis (host catalog no. ULLZ 5916 [ USNM 1541194 ]), coll. D.L. Felder, 29.09.2000 .

Description. See Anker (2011) for a description of a small (presumably young) individual. For the description of a larger adult, see the description of Leptalpheus canterakintzi ( Anker & Lazarus 2015) .

Color in life. Smaller individuals semitransparent with sparse red chromatophores on antennal and antennular peduncles, uropods, telson, and forming diffuse transverse bands on anterior margins of the abdominal somites (see Anker 2011: fig. 7). Larger individuals with denser red chromatophores in all these regions as well as the carapace and chelipeds, giving the body a generally pinkish hue; major chela distally hyaline-white (see Anker & Lazarus 2015: fig. 7).

Type Locality. Playa El Agallito near Chitré, Pacific coast, Panama .

Distribution. Tropical eastern Pacific region: Colombia ( Anker & Lazarus 2015), Panama ( Anker 2011), and Nicaragua ( Felder et al. 2003; present study).

Ecology. Obligate burrow cohabitant of laomediid mudshrimps in the genus Axianassa : associated with Axianassa darrylfelderi Anker & Lazarus, 2015 in Colombia ( Anker & Lazarus 2015) and Axianassa canalis Kensley & Heard, 1990 in Nicaragua (present study).

Remarks. The type series of L. azuero , collected from the Pacific coast of Panama, were all small-bodied individuals (cl 2.4–3.7 mm). Conversely, L. canterakintzi was described from a considerably larger specimen (cl 6.0 mm). Given the significantly low genetic distance between 16S sequences of L. azuero and L. canterakintzi discussed above, it appears that L. azuero and L. canterakintzi represent different developmental stages of the same species. This conclusion is further supported by the fact that L. azuero was reported from the type locality of L. canterakintzi ( Anker & Lazarus 2015) and later collection efforts at the type locality of L. azuero did not yield specimens matching the description of L. azuero but did yield those matching the description of L. canterakintzi (A. Anker, pers. comm.).

The two species were morphologically differentiated based on two characters: (1) the presence of stout spiniform setae on the ischium of the third and fourth pereopods (vs. absent in L. canterakintzi ) and (2) the pollex of the major cheliped terminating in a bidentate tip, with an acute tip perpendicular to the pollex axis and a secondary distal tooth oblique to the pollex axis in L. azuero (vs. terminating in a blunt tip without secondary tooth in L. canterakintzi ). All specimens examined herein except for the type specimens lacked spines on the ischium of the pereopods. The pollex of the major cheliped of a Nicaraguan specimen of body size between those of the type series of the two species (cl 4.7 mm) resembled the description of L. azuero ; however, the pollex tip was considerably blunter than the type specimens of L. azuero and the secondary distal tooth was slightly smaller, potentially representing an intermediate morphological stage (compare Fig. 21a, b vs. Anker 2011: fig. 6). Conversely, larger Nicaraguan specimens had major chelipeds that morphologically matched the description of L. canterakintzi ( Fig. 21c–e ). Given the combination of low genetic distances between the paratype of L. azuero and specimens morphologically matching the type description of L. canterakintzi , as well as the existence of specimens morphologically intermediate between the two type descriptions, we find L. canterakinzti to be a junior synonym of L. azuero .

Larger specimens of this species are nearly indistinguishable from specimens of the western Atlantic L. axianassae , differing only by the proportions of the third pereopod, which led Anker & Lazarus (2015) to hypothesize that these two species represent transisthmian sister species, a conclusion supported by our phylogenetic analysis. Interestingly, none of the smaller-bodied specimens of L. axianassae examined in this study had major cheliped morphologies resembling those of smaller specimens of L. azuero , suggesting that this transitional stage may be unique to L. azuero .

Figures

FIGURE 21. Leptalpheus azuero Anker, 2011 (a–e), Leptalpheus felderi Anker, Vera Caripe & Lira, 2006 (f–h), and Leptalpheus forceps Williams, 1965 (i–k). Leptalpheus azuero: ovigerous female (cl 4.7 mm), ULLZ 11823 [USNM 1545912], from Las Peñitas, Nicaragua (a, b) and ovigerous female (cl 6.4 mm), ULLZ 5917 [USNM 1541195], from Estero Aserradores, Nicaragua (c–e): a, major chela, lateral; b, same, mesial; c, major chela, dorsolateral; d, same, dactylus and pollex, dorsolateral; e, same, fingers opened, lateral. Leptalpheus felderi: male (cl 8.5 mm), UF 48038, from Wachapreague, Virginia, USA: f, major chela, mesial; g, same, dorsolateral; h, same, dactylus and pollex, dorsolateral. Leptalpheus forceps: male (cl 8.8 mm) (i), female (cl 5.3 mm) (j), ULLZ 18053 [USNM 1706385], from Bay St. Louis, Mississippi, USA and female (cl 6.0 mm) (k), ULLZ 5593 [USNM 1541048], from Nuevo Campechito, Mexico: i, frontal margin, dorsal; j, same; k, uropod with caudal appendix, dorsal.