Morphological, morphometric, meristic and osteological evidence for two species of hake (Actinopterygii: Gadiformes: Merluccius) in Argentinean waters

Abstract

Morphologically, both classic and landmark-based morphometry and meristic analyses of 241 specimens of Merluccius, along with the re-examination of six paratype specimens of Merluccius hubbsi, the holotype and three paratypes of Merluccius patagonicus and the syntype of Merluccius australis revealed the presence of only two species of Merluccius in Argentinean waters. Internal structures (hyomandibula, urohyal and sagitta otolith) of M. hubbsi were compared to those reported for M. patagonicus and were shown to have identical morphology. Type specimens of M. patagonicus showed a complete overlap in morphometric and meristic characters with M. hubbsi, whereas M. australis had a greater number of second dorsal and anal-fin rays, and more lateral-line scales. In addition, M. australis had a smaller eye and longer snout than M. hubbsi and M. patagonicus. The results indicate that there is no evidence for a third hake species in Argentinean waters. Merluccius patagonicus is a synonym of M. hubbsi.

Phylogenetic prospecting for cryptic species of the genus Merluccius (Actinopterygii: Merlucciidae)

“…hubb153.2) but branched between the clusters of Austral hakes and Pacific hakes. Likewise, M. tasmanicus 24 and M. polylepis from the Southern Ocean 32 had been proposed as synonymous of M. australis 6,29,30 . However, their phylogenetic status was much like the rest of morphotypes, e.g.…”

“…Also, meristic (see Fig. 1 from 23 ) and molecular analyses 29,30 showed that M. patagonicus could be synonymous with M. hubbsi and that M. tasmanicus could be synonymous with M. australis 31 . Taxonomic uncertainties are expected in closelyrelated species that show extensive overlap in morphological and meristic traits.…”

A multivariate morphometric investigation to delineate stock structure of gangetic whiting, Sillaginopsis panijus (Teleostei: Sillaginidae)

“…The actual reasons for morphometric variation between populations are often fairly tough to describe. However, several studies have found variations because of the environmental conditions, geographic position, ecological change and sometimes human error during work on morphometric measurements and meristic counts (Cabral et al 2003 ; Díaz de Astarloa et al 2011 ; Chaklader et al 2016a ).…”

Otoliths sagittae of Merluccius hubbsi: an efficient tool for the differentiation of stocks in the Southwestern Atlantic

“…Several studies have investigated the economic importance, biological, ecological and fishing aspects of M. hubbsi. The most recent contributions are on juvenile growth (BURATTI; SANTOS, 2010;LORENZO et al, 2011), foraging strategies (TEMPERONI et al, 2013;BELLEGGIA et al, 2014), systematics (DÍAZ-DE-ASTARLOA et al, 2011) and differences in reproductive aspects and larval development (BETTI et al, 2014;MACCHI et al, 2016). The majority of them came from the Argentina and none is related to use of otolith morphology and morphometry to ascertain geographic variation of the species.…”