Jenynsia obscura (Weyenbergh, 1877)

Koerber, Stefan & Azpelicueta, María De Las Mercedes, 2009, On two Jenynsia taxa (Cyprinodontiformes: Anablepidae) from Argentina, originally placed in the poeciliid genus Xiphophorus, Zootaxa 2028, pp. 51-58 : 53-56

Jenynsia obscura (Weyenbergh, 1877)

As listed by Tortonese (1963), the syntype series of X. obscurus consists of three specimens (MSNG 33705). Surprisingly and overlooked so far, one of them is a very small, badly preserved parodontid specimen. The other two specimens, one male (25.7 mm SL, fig. 3) and one female (28.2 mm SL) are in fair condition and undoubtedly belong to the genus Jenynsia . Both specimens have 22–23 small scales in the predorsal series (fig. 4–5), 35–36 scales in the lateral line series, five scales above and seven below the lateral line series, and 16 scales surrounding the caudal peduncle. The male has long pectoral fins almost reaching the pelvic fin origin. The pelvic fins are small (both fins broken in female) and the dorsal fin is located scarcely posterior to anal-fin origin or at the same level in the female. The gonopodium is tubular. The dorsal profile of the body is straight and the body depth is low. Although the specimens are brownish, they still have a pigmentation pattern different from that of J. multidentata with a high number of chromatophores widespread on dorsal half of the flank, between the mid-dorsal and the lateral line, resulting in a darker area; a very slender line of pigments along the lateral series in the middle of the flank and some vertical spots close to the mid-dorsal line also are still visible. The counts are (the first taken from the male specimen): dorsal-fin rays 9–10, anal-fin rays 10, pectoral-fin rays 17 (broken in female), pelvic-fin rays 6. Measurements in % of SL: head 27.0–29.9, predorsal length 60.3–59.2, body depth 23.0–24.2. Measurements in % of HL: eye 31.8–29.4, interorbital 42.0–40.0.

Based on the high quantity of scales in the predorsal line – a character unique in Jenynsia ( Ghedotti & Weitzman 1995, Aguilera & Mirande 2005) – we consider Xiphophorus obscurus to be a senior synonym of Jenynsia pygogramma Boulenger, 1902 (fig. 4–7). Furthermore both share as their type localities the town of Cruz del Eje in the northern part of the Argentinean province of Córdoba (30°43’S 64°48’W), located within the endorheic system of río Cruz del Eje, isolated from the la Plata basin. We were unable to locate the laguna Ojo de Agua in the surroundings of Cruz del Eje, mentioned by Weyenbergh as the exact collection site. Only a few kilometres south of the town a hydroelectric dam was erected in the 1940ies which today is fed by some of the brooks and rivers mentioned in part by Weyenbergh. The lagoon has possibly been destroyed during the filling of the artificial lake.

papers that could be considered in the sense of ICZN 23.9.1.2 are identified in third column. Those that need to be

excluded from consideration for the reasons given in 23.9.6 are marked in last column.

López, Protogino & Aquino X

Ringuelet et al. (1967) assigned the description of Jenynsia obscura to the year 1875. In the title of the description Weyenbergh (1877a) noted that the collection of specimens occurred in March of 1876 and wrote his paper in August of 1876, being both facts contradictory to Ringuelet’s assignment. The Boletín de la Academia Nacional de Ciencias has been published in issues which later were bound into volumes. Unfortunately the binder assigned the publishing year of the first issue, 1875, to the whole volume. The third issue, containing Weyenbergh’s paper, was published in 1877 (Luis Acosta, pers. com.).

Weyenbergh (1877b) published a second description of Jenynsia obscura as a new species in the Actas de la Academia Nacional de Ciencias Exactas de Córdoba. He mentioned the type locality only in the Boletín, whereas in the Actas he provided the more complete description. Although based on this information we now can confirm 1877 as the correct year of publication, we are not able to determine which of the two papers should be considered as the original description. Only the finding of unbound issues of the Boletín will reveal more precise dates of publication as the individual covers of these were removed during the binding process.

Although Jenynsia pygogramma (fig. 6–7) is a taxon well known from recent papers dealing with Anablepidae it cannot be preserved as a nomen protectum because the requirements of the ICZN are not fulfilled. In most of the papers published in Argentina during the last century, Jenynsia pygogramma was not listed as a valid species, but still considered a junior synonym of Jenynsia lineata . Table 1 provides a chronological list of the published works in which Jenynsia pygogramma Boulenger, 1902 (occasionally misspelled as pyrogramma) has been considered as a valid species during the last 50 years (1958–2008) and shows that we were unable to identify the 25 works required by the ICZN.

Thus, following the law of priority we hereby consider Jenynsia obscura (Weyenbergh, 1877) the valid name of the species and place Jenynsia pygogramma Boulenger, 1902 into its synonymy.

To separate the two specimens of Jenynsia obscura from the parodontid that was included erroneously in the type series, we hereby designate new type statuses as follows: Jenynsia obscura , 1 male, lectotype (MSNG 33705); J. obscura , 1 female, paralectotype (MSNG 54297, ex 33705); Parodontidae sp., 1 specimen, paralectotype (MSNG 54298, ex 33705, fig. 8–9).

Tables

TABLE 1. Papers in which Jenynsia pygogramma has been treated as a valid species between 1958 and 2008. Only 19

Year 1967	Author/s Ringuelet, Arámburu & Alonso de Arámburu	23.9.1.2 X	23.9.6
1975	Ringuelet	X
1977 1981	Ringuelet Parenti	X X
1983 1984 1987	Arratia, Peñafort & Menu-Marque Menni, López, Casciotta & Miquelarena López, Menni & Miquelarena	X X	X
1995	Ghedotti & Weitzman	X
1996	Ghedotti & Weitzman Haro & Bistoni	X	X