A new species of ladyfish, of the genus Elops (Elopiformes: Elopidae), from the western Atlantic Ocean

Abstract

v This paper describes Elops smithi, n. sp., and designates a lectotype for E. saurus. These two species can be separated from the five other species of Elops by a combination of vertebrae and gillraker counts. Morphologically, they can be distinguished from each other only by myomere (larvae) or vertebrae (adults) counts. Elops smithi has 73–80 centra (total number of vertebrae), usually with 75–78 centra; E. saurus has 79–87 centra, usually with 81–85 centra. No other morphological character is known to separate E. smithi and E. saurus, but the sequence divergence in mtDNA cytochrome b (d = 0.023–0.029) between E. smithi and E. saurus is similar to or greater than that measured between recognized species of Elops in different ocean basins. Both species occur in the western Atlantic Ocean, principally allopatrically but with areas of sympatry, probably via larval dispersal of E. smithi by oceanographic currents.

Southernmost record of Elops smithi in the Southwest Atlantic. A tropical species in waters of Patagonia, Argentina

“…This specimen was filleted for vertebrae counts and unfortunately it could not be kept. Additional morphometric and meristic measurements were performed on the two specimens preserved in ichthyological collections following McBride et al (2010) (Table 1). The maximum Tl recorded for E .…”

“…smithi (De Sousa et al, 2019; Machado et al, 2012). Consequently, we consider that at least part of the existing information of these species may be confounded and we urge future studies on Elops genus to consider diagnostic characteristic indicated by McBride et al (2010).…”

“…However, Smith (1989) identified the presence of two sympatric larval morphs along the eastern seaboard of the US and gulf of México, distinguished by the number of myomeres. Based on the analysis of mitochondrial Cytb sequences and morphological data, McBride et al (2010) confirmed that the morph with the lower myomere count was, in fact, a distinct species, which they denominated Elops smithi McBride et al, 2010. Both species occur in the western Atlantic Ocean (McBride et al, 2010).…”

“…Until recently, the ladyfish Elops saurus (Linnaeus, 1766), was the only living known elopid species (McBride et al, 2010; Obermiller & Pfeiler, 2003). However, Smith (1989) identified the presence of two sympatric larval morphs along the eastern seaboard of the US and gulf of México, distinguished by the number of myomeres.…”

“…Until recently, the ladyfish Elops saurus (Linnaeus, 1766), was the only living known elopid species (McBride et al, 2010;Obermiller & Pfeiler, 2003). However, Smith (1989) (Franco et al, 2014;Garcia-Junior et al, 2015;Marceniuk et al, 2017;Medeiros et al, 2018;Mendes et al, 2018;Pinheiro et al, 2015), and recently, Milessi et al (2012) documented the presence of E. saurus in Laguna de Rocha in Uruguay (34°33′S-54°22'W) and in the northern coast of Argentina (37°59'S-57°27′W).…”