Morphological description of Dipturus mennii (Chondrichthyes: Elasmobranchii: Rajidae) and its differentiation from Dipturus trachyderma

Abstract

Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium) of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachyderma (Krefft & Stehmann, 1975), a species that may be confused with D. mennii; we further corroborate, through anatomical features, that these species warrant separate taxonomic recognition. The main differences between D. mennii and D. trachyderma were found in squamation of the nuchal and middisc region, neurocranium, pectoral girdle, and principally the clasper skeleton. The morphology of the pelvic girdle is similar in both species. Dipturus is characterized by having the ventral terminal cartilage J-shaped (as opposed to the Z-shaped ventral terminal cartilage in Zearaja, whose species were, until recently, placed in Dipturus). Additional characters that may be derived for Dipturus include the anterior rostral groove and elevated rostral proportion

Clasper morphology of skates of the tribe Riorajini (Chondrichthyes: Rajiformes: Arhynchobatidae) and its systematic significance

“…The fleshy integument between the proximal and distal clefts found in A. cyclophora is not internally associated to a cartilaginous element, differing from the component terminal bridge described in most skates between the proximal and distal clefts (Hulley, ; Ishiyama, ; Moreira, Gomes, & Carvalho, ; Stehmann, ). Therefore, the clasper of A. platana and A. castelnaui are more similar to each other than to A. cyclophora by presenting a slender projection and a fleshy integument that conceals a thin spike (internally supported by the accessory terminal 2 cartilage).…”

Conhecimento da diversidade dos Chondrichthyes marinhos no Brasil: a contribuição de José Lima de Figueiredo

“…Do ponto de vista morfológico é um grupo muito uniforme, a maioria das espécies é bentônica e de distribuição geográfica restrita, com alto grau de endemismo, fatores que geram grande riqueza de espécies em levantamentos regionais, bem como dificuldade de identificação dos táxons (Ebert & Compagno, 2007). O conhecimento deste grupo no Brasil aumentou consideravelmente nos últimos anos com o incremento do esforço amostral em ambiente da borda do talude em grandes profundidades (Gomes & Paragó, 2001;Gomes & Picado, 2001;Gomes & Costa, 2003;Carvalho et al, 2005;Moreira et al, 2011;U.L. Gomes, com.…”

Skate-ing on thin ice: molecular ecology of longnose skates in the Southeast Pacific Ocean

“…However, the presence of the accessory terminal I cartilage (Atr1) was erroneously reported by Menni (1971) and Leible (1987), as there is no equivalent structure in Zearaja species (Last & Gledhill, 2007 (Krefft & Stehmann, 1975) and subsequent description (Leible & Stehmann, 1987) included details of external and internal structures, such as neurocranium, pelvic girdles, scapulocoracoid and clasper; and where the presence of Atr1 and the sentinel (both absent in Zearaja) were reported. Moreira et al, (2011) found differences in the neurocranium, scapulocoracoid and clasper between D. menni and D. trachyderma, which was consistent with there being two separate species, even though some specimens of D. menni…”