Anchoviella juruasanga, Loeb, 2012

Loeb, Marina V., 2012, A new species of Anchoviella Fowler, 1911 (Clupeiformes: Engraulidae) from the Amazon basin, Brazil, Neotropical Ichthyology 10 (1), pp. 13-18 : 14-16

Anchoviella juruasanga , new species

Figs. 1-2

Holotype. MZUSP 109249 , 42.4 mm SL. Brazil, Pará, rio Trombetas, upstream from mouth of Lago do Jacaré at Reserva Biológica de Trombetas , 01°20’S 56°51’W, 2 Aug 1979, R. M. C. Castro.

Paratypes. ANSP 192138 (20, 42.7-48.1mm SL) , MNRJ 39086 (20, 42.0- 49.8 mm SL) , MPEG 22814 (20, 44.0- 48.5 mm SL) , MZUSP 15831 (243, 42.0- 52.8 mm SL), all collected with holotype . INPA 7104 (30, 26.1-42.3 mm SL), Pará, rio Tapajós, near mouth of rio Cupari , 03°36’22.79”S 55°19’13.76”W, 26 Oct 1991, L. Rapp Py-Daniel & J. Zuanon . MZUSP 31422 (1, 39.2 mm SL), Rondônia, rio Madeira at Calama , 08°03’S 62°53’W, 9 Dec 1980, M. Goulding . MZUSP 52015 (2, 23.1-26.7 mm SL), Rondônia, rio Machado near its mouth, 08°04’S 62°4’W, 21 Nov 1970, Expedição Permanente à Amazônia . MZUSP 85397 (5, 21.90-25.80 mm SL), Rondônia, rio Machado near its mouth, 21 Nov 1975, Expedição Permanente à Amazônia .

Non-type specimens examined. MZUSP 8554 (1, 33.73 mm SL), Pará, Santarém, rio Tapajós , 02°25’S, 54°44’W, Dec 1967, Expedição Permanente à Amazônia . MZUSP 9228 (2, 19.77-19.87 mm SL), Pará, Santarém, rio Maicá , 02°35’S 54°22’W, 19-27 Oct 1971, Expedição Permanente à Amazônia . MZUSP 9420 (5, 38.69-40.83 mm SL), Pará, Santarém, rio Tapajós , 02°25’S 54°44’W, 10 Jan 1968, Expedição Permanente à Amazônia . MZUSP 18155 (3, 37.47-39.96 mm SL), Pará, Jatobal, rio Tocantins , 04°34’S 49°39’W, 17 Nov 1970, Expedição Permanente à Amazônia . MZUSP 28049 (2, 12.42- 23.27 mm SL) Amazonas, Ayrão Velho, rio Negro , north of ecological reserve of Anavilhanas , 06 Nov 1982, L. P. S. Portugal . MZUSP 29096 (5, 21.82-23.8 mm SL), Roraima, Marará, rio Branco , 01°30’S 61°16’W, 26 Oct 1979, M. Goulding . MZUSP 29121 (19, 24.29- 30.86 mm SL), and MZUSP 29122 (88, 73, 20.22-26.12 mm SL), Roraima, Marará, rio Branco , 01°30’S 61°16’W, 26 Oct 1979, M. Goulding . MZUSP 29123 (253, 24.33-32.41 mm SL), Rondônia, rio Madeira, at the junction with rio Machado , 08°04’S, 62°54’W, 15 Dec 1980, M. Goulding . MZUSP 73533 (1, 19.22 mm SL), Roraima, Marará, rio Branco , 01°30’S 61°16’W, 28 Oct 1979, M. Goulding . MZUSP 74315 (57, 18.94-22.21 mm SL), Roraima, Caracaraí, rio Branco near its mouth, 01°20’S 61°50’W, 12 Nov 1979, L. P. S. Portugal . MZUSP 85218 (3, 21.81-28.99 mm SL), Rondônia, rio Machado near its mouth, 08°04’S 62°54’W, 21 Nov 1975, Expedição Permanente à Amazônia . MZUSP 93487 (202, 18.79-26.9 mm SL), Pará, Pimental, rio Tapajós , 04°34’15”S, 56°15’39”W, 11 Nov 2006, L. M. Sousa & J. L. Birindelli . MZUSP 97302 (36, 21.70-30.20 mm SL), Pará, Novo Progresso, rio Jamanxim , near Vila Mil , 23 Oct. 2007, J. L. Birindelli et. al . MZUSP 97431 (78, 26.20-29.40 mm SL), Pará, Novo Progresso, rio Jamanxim , 07°43’51”S 55°16’36”W, 23 Oct 2007, J. L. Birindelli et al . MZUSP 102330 (105, 24.10-50.60 mm SL), Amapá, rio Jari, downstream of Cachoeira Santo Antônio , 00°46’54”S, 52°31’48”W, 11 Oct 2007, M. Carvalho et.al .

M. V. Loeb 15

Diagnosis. Anchoviella juruasanga is distinguished from its congeners by having a short upper jaw, with its posterior tip extending between the verticals through anterior and posterior margins of the pupil (vs. posterior tip of upper jaw extending beyond the vertical through posterior margin of the pupil). Anchoviella juruasanga is also distinct from other strictly freshwater Amazonian species of the genus by the distance from tip of snout to posterior end of upper jaw between 8 and 11% in SL (vs. 14% or more in A. alleni , A. carrikeri , A. guianensis , and A. jamesi ). The anal-fin origin slightly posterior to or at the vertical through the base of the last dorsal-fin ray further distinguishes the new species from A. alleni (anal-fin origin posterior to the vertical through the last anal-fin ray by at least 14% of HL) and A. jamesi (anal-fin origin anterior to the vertical through the last anal-fin ray).

Description. Morphometric data of holotype and 40 paratypes is presented in Table 1 . Body elongated, compressed laterally; greatest body depth at dorsal-fin origin. Dorsal body profile convex from snout tip to nostril, gently convex from nostril to dorsal-fin origin, approximately straight from latter point to caudal peduncle. Ventral body profile convex from anterior tip of lower jaw to posterior margin of orbit, gently convex from vertical through posterior margin of orbit to the posterior end of anal-fin base, nearly straight from latter point to the mm SL, rio Trombetas, Trombetas, Pará State.

origin of lower caudal fin lobe. Caudal peduncle longer than deep. Vertebrae 39-40 (2 specimens examined).

Mouth inclined relative to body axis, sub-terminal, posterior tip of upper jaw rounded. Snout long, pointed in lateral view. Anterior tip of upper jaw distant from tip of snout by about 7.3 to 8.8% of HL. Posterior margin of upper jaw rounded, its posterior tip extending between the verticals through anterior and posterior margins of the pupil. Teeth pointed, small, slender, slightly recurved posteriorly, arranged in a single row in the premaxilla, maxilla and lower jaw.

Eye lateral on head, located dorsal to horizontal through pectoral-fin insertion; eye visible in dorsal and ventral views. Two confluent nostrils on each side of the head, the anterior elliptical and the posterior larger crescent-shaped. Lateral line absent.

Dorsal-fin rays ii-iii+11-12, origin closer to base of caudal fin than to tip of snout, not reaching the latter by 2.0 to 6.2% of SL, distal margin approximately straight. Anal-fin rays iiiii+12-13, its origin at vertical through base of last dorsal-fin ray, anterior rays longer. Pectoral-fin rays i+11-13, distal tip of longest pectoral-fin ray not reaching pelvic-fin origin by 6.0 to 13.0% of SL, distal margin slightly convex. Pectoralfin axillary scale absent in most specimens, probably lost during collecting or storage. Pelvic fin-rays i+6, distal tip of longest pelvic-fin ray not reaching anal-fin origin by 4.0 to 16 A new species of Anchoviella from Brazil

9.9% of SL, distal margin slightly convex. Pelvic-fin axillary scale absent in most specimens, probably lost during collecting or storage. Base of anteriormost pelvic-fin ray closer to anal-fin origin than to base of anteriormost pectoralfin ray, failing to reach the latter by about 2.6 to 4.8% of SL. Caudal fin forked, upper and lower lobes equally developed. Caudal-fin rays 5,10/10,5.

Pseudobranchia present, shorter than eye, approximately 18 to 23% of HL. Gill rakers long and thin in the first branchial arch, 8-12 on the upper branch, 16-22 on the lower branch, 25 to 34 in total. Length of raker inserted in the angle of first gill arch between 14-17% of HL.

Coloration in alcohol. Body coloration pale to light yellowish or brownish. Longitudinal stripe pale to silver, absent in most preserved specimens, when present extending from posterior margin of head to caudal peduncle; width of the stripe 10-20% of HL at vertical through pectoral-fin origin, increasing posteriorly to 20-35% of HL at vertical through anal-fin origin. Dark spots present above and below the lateral stripe in some specimens, on top of the head, along the dorsum from origin of dorsal fin to caudal fin, along the ventrum, from origin of anal fin to caudal fin; also present along base of dorsal, anal, and caudal fins, and arranged in two vertical parallel stripes at caudal fin. Orbit and middle portion of the postorbital region in the head translucent to silver.

Coloration of freshly preserved specimens. Description of the coloration of freshly preserved specimens is based on a single specimen (MZUSP 103314, paratype, 46 mm SL; Fig. 2 ). Dorsum from the vertical through opercle to caudal fin above the longitudinal stripe translucent with dark spots; ventrum translucent from the vertical through opercle to caudal fin above the longitudinal stripe; posteriormost portion of upper and lower jaw and posteriormost portion of preorbital region also translucent. Dark spots present above the longitudinal stripe along body, on top of the head, along base of dorsal, anal and caudal fins, and also arranged in two vertical parallel stripes at caudal fin. Tip of upper and lower jaw, top of the head, base of dorsal and anal fins, above the longitudinal stripe, along the dorsum at caudal peduncle and at the anteriormost portion of caudal fin light yellowish. Postorbital region and longitudinal stripe along body silver, width of the stripe 25% of HL at vertical through pectoral-fin origin, increasing posteriorly to 30% of HL at vertical through anal-fin origin.

Etymology. In the Tupi language “juru” means mouth and “asanga” means short. The epithet juruasanga , thus, refers to the short maxilla, a diagnostic character of the species among congeners.

Distribution. Anchoviella juruasanga is known from tributaries of the middle and lower Amazon basin, Brazil, including rio Tapajós, rio Negro, rio Branco, rio Madeira, rio Trombetas, rio Tocantins, rio Maicá, and rio Jari ( Fig. 3 ).

Remarks. Anchoviella juruasanga is similar in terms of external morphology to A. jamesi and Amazonsprattus scintilla Roberts, 1984 , which are paedomorphic engraulids known to co-occur with A. juruasanga in some rivers of the Amazon basin, such as the rio Jari. These three species share a short upper jaw, which, nevertheless, differs in terms of relative lengths. In A. jamesi the posterior tip of the upper jaw extends beyond the vertical through the posterior margin of the orbit by about ¼ the orbit diameter. The upper jaw of A. juruasanga is shorter than that of A. jamesi , with its posterior tip extending between the verticals through anterior and posterior margins of the pupil. In Amazonsprattus scintilla the upper jaw is extremely short compared to the condition typically present in the Engraulidae , and its posterior tip is located in a region anterior to the vertical through the anterior margin of the orbit (Whitehead et al., 1988). Another morphological difference between these three species is the relative position of the fins: in A. juruasanga the anal-fin origin is located in a region immediately posterior to the vertical through the base of the last dorsal-fin ray, whereas in Amazonsprattus scintilla and in A. jamesi the anal-fin origin is located at the vertical through the anterior quarter of the dorsal-fin base. The non-type material listed in the description was used in the color diagnosis, and also for inferring the distribution of the species.

Figures

Fig. 1. Anchoviella juruasanga, holotype, MZUSP 15831, 42.4

Fig. 2. Anchoviella juruasanga, freshly preserved specimen, MZUSP 103314, 46.0 mm SL, rio Jari, Monte Dourado, Pará State. Photo by J. L. Birindelli (MZUSP).

Fig. 3. Distribution map of Anchoviella juruasanga. Holotype indicated by white circle; paratypes and non-type material indicated by red circles.