Limia mandibularis, Rodriguez-Silva & Torres-Pineda & Josaphat, 2020

Rodriguez-Silva, Rodet, Torres-Pineda, Patricia & Josaphat, James, 2020, Limia mandibularis, a new livebearing fish (Cyprinodontiformes: Poeciliidae) from Lake Miragoane, Haiti, Zootaxa 4768 (3), pp. 395-404 : 397-401

Limia mandibularis , sp. nov.

( Figs. 2-6 , Tables 1 and 2)

Holotype. OMNH 86828 , adult male 35.5 mm SL ( Fig. 2 ), Lake Miragoane , Haiti; coordinates 18°25’33.2” N, 73°02’56.9”W; R. Rodriguez-Silva, P. Torres-Pineda, J. Josaphat, and P. Michard Beaujour, June 5, 2019

Paratypes. Same origin, date and collectors as holotype. OMNH 86829 , 1 female, 41.0 mm SL ( Fig. 2 ) ; OMNH 86831 , 1 male, 38.5 mm SL and 1 female, 41.5 mm SL (cleared and stained specimens) ; OMNH 86832 , lot of 5 females, 36.0- 41.5 mm SL ; MNHNSD.22.10426, 1 female, 39.5 mm SL ; MNHNSD.22.10427, 1 female, 33.0 mm SL : MNHNSD.22.10428, 1 female, 33.0 mm SL .

Diagnosis. Limia mandibularis sp. nov. is uniquely diagnosed by the presence of a well-developed lower jaw due to the presence of an elongate anguloarticular bone ( Fig. 3 ). The new species can also be identified by the lack of preorbital and preopercular pores and by the presence of single preorbital and preopercular canals forming open grooves ( Fig. 4 ). Limia mandibularis sp. nov. can be further distinguished by the combination of the following characters: dorsal fin with 8 rays and its origin is slightly behind of the origin of the anal fin in females; 13 predorsal scales; caudal fin symmetrical and truncate or slightly convex; no crossbars, spots or blotches on body in both sexes. See additional comments in the Discussion below.

Description. Elongate body with deep caudal peduncle. Post-anal region moderately compressed towards caudal peduncle. Dorsal profile slightly concave from snout tip to posterior edge of eye; convex from middle of eye to origin of dorsal fin; slightly concave or straight from dorsal fin origin to caudal fin. Ventral profile convex with distinctive protuberance in the lower jaw area that is formed by the joint of anguloarticular and quadrate bones (quadrato-mandibular joint). Post-anal profile slightly concave or straight ( Fig. 2 ). Gonopodial segments of ray 4p serrae 11 ( Fig. 5 ). Predorsal scales 12 to 13 (usually 13) and lateral scales 26 to 28 (usually 26). Dorsal fin with 8 rays ( Table 1). Caudal fin with 15 to 17 rays (usually 16), truncate or slightly convex, and symmetrical in both sexes. Mouth wide and superiorly oriented. Teeth of outer row conical in upper and lower jaws. Vertebral column with 30 vertebrae.

Color of preserved specimens. Dorsal and middle portion of body dark, with noticeable reticulated pattern due to black pigmentation on edges of scales. Ventral region of body and scales of the hypural area with tannish coloration, much darker below pectoral fins. All fins hyaline ( Fig. 2 ).

Color in live specimens. Yellowish background towards dorsal region of body, darker in snout and above opercula. Ventral region with silver coloration. No distinctive features like spots, bars or blotches on body or fins in both sexes ( Fig. 6 ).

Distribution and ecological notes. Limia mandibularis sp. nov. is only known from the north bight of Lake Miragoane in Haiti. The lake seems very isolated in terms of connectivity with other water bodies as we did not see any tributary river or stream, but only mountain springs that lead to the lake. Our observations agree with the classification of Curtis & Hodell (1993) of the lake as an endorheic drainage. The species herein described was collected in a clear water path with slow current exiting the lake. Water temperature was 29.9 °C and water conductivity was 321 microS/cm on the collecting date (June 5 th, 2019). The area is characterized by the presence of muddy bottoms and some semi-submerged and submerged vegetation growing near the banks ( Fig. 7 ). Limia mandibularis was sympatric with Gambusia beebei , five other Limia species ( L. miragoanensis , L. immaculata , L. nigrofasciata , L. garnieri and L. islai ), Nandopsis haitiensis and two species of African cichlids introduced in the lake ( Oreochromis aureus and Tilapia sp.).

Etymology. The specific epithet mandibularis , from the Latin mandibula (jaw), is in reference to the well-developed lower jaw, a character that distinguishes the species. The vernacular name “Jawed Limia ” is proposed for this species, due to the distinct protuberance that can be seen in the lower jaw.

Figures

FIGURE 2. Limia mandibularis sp. nov., holotype OMNH 86828, adult male 35.5 mm SL (top) and paratype OMNH 86829, adult female 41.0 mm SL (bottom).

FIGURE 3. Mouth of a cleared specimen of Limia mandibularis sp. nov. (OMNH 86831, female, 41.5 mm SL) showing the peculiar arrangement of bones of the upper and lower jaws. Premax: premaxillar, max: maxilla, dent: dentary, ang: anguloarticular, qu: quadrate

FIGURE 4. Head of Limia mandibularis sp. nov. showing the protuberance in the lower jaw (a), the single preorbital canal forming an open groove (b) and the single preopercular canal forming an open groove (c). Red lines show the quadrato-mandibular joint forming nearly a right angle between the front of the mouth and the inferior edge of the eye globe.

FIGURE 5. Cleared and stained gonopodium tip of Limia mandibularis sp. nov., paratype OMNH 86831, adult male, 38.5 mm SL.

FIGURE 6. Female of Limia mandibularis sp. nov (48.5 mm SL) showing coloration in a live specimen.

FIGURE 7. Habitat where Limia mandibularis sp. nov. was collected. The locality is found at the north end of Lake Miragoane and corresponds with locality represented by the white circle in Figure 1.