Sexual dimorphism in two catfish species, Mystus pelusius (Solander, 1794) and Glyptothorax silviae Coad, 1981 (Teleostei: Siluriformes)

Abstract

Sexual dimorphism of two catfish, Mystus pelusius (Solander, 1794) and Glyptothorax silviae Coad, 1981, is presented based on the examination of external morphology of the fish and morphology of the gonads. We observed sexual dimorphism for M. pelusius in the shape and position of the genital papilla. In the male, the genital papilla was a small, fleshy, pointed and broad-based structure. The pelvic fin was short and did not reach back to the genital papilla. In females of M. pelusius the opening of the genital structure was without any protrusion or with a very small, dot-like structure in a few specimens, which the pelvic fin reached and overlapped. In females of G. silviae, the base of the round genital structure was wider and had a small round protrusion. The color of the female was also darker in comparison with the male. In males the base of the round genital structure was narrower and had a longer pointed protrusion. The male body color was lighter than that of females.

An Investigation of ZZ/ZW and XX/XY Sex Determination Systems in North African Catfish (Clarias gariepinus, Burchell, 1822)

“…The sampled individuals were randomly picked from a large breeding stock to avoid the probability of high incidence of siblings in our pool. The sex of each individual was identified by external morphology and internal examination of gonadal morphology (Kitano et al, 2007;Esmaeili et al, 2017;Ponjarat et al, 2019). Hence, the sex of all specimens obtained from the Department of Aquaculture, Faculty of Fisheries, Kasetsart University (Bangkok, Thailand) was determined to avoid potentially wrong sexing due to sex reversal.…”

Sexual dimorphism in morphometric characters of Mystus singaringan from Klawing River in Central Java, Indonesia: Strategic instruction for conservation development

“…In this study, sexual dimorphism of M. singaringan can be determined from 12 significantly different morphometric characters and from 12 other morphometric characters that are not significantly different (Table 2). However, other fish from Bagridae family, such as Mystus pelusius, do not show any different form of sexual dimorphism in terms of body size (Esmaeili et al 2017), whereas in Mystus gulio, standard length, body depth, and head length become markers for sexual dimorphism of male and female fish (Begum et al 2008). Those different results indicate that each fish species has different absolute size (Nugroho et al 2016) and has certain geographical distribution which is controlled by the physical conditions of the environment (Ariyanto and Imro 2008).…”

“…In addition, sexual dimorphism can also be interpreted as the variation of intraspecific phenotype (McGee and Wainright 2013). Sexual dimorphism can be identified from primary sexual characters, namely genital papilla or genital pore (Musa and Bhuiyan 2006;Esmaeili et al 2017), and from secondary characteristics of color, body size, morphology, physical strength and other body characters (Dimijan 2005), the relation between length and condition factor (Nahar et al 2018). However, sexual dimorphism of some taxa is often unclear (Levitan 2005) and vague when it is observed by unaided eye (Andersson et al 1994).…”

“…Understanding on sexual dimorphism is very important and some findings conveyed by sexual dimorphism can give many valuable information, such as the process of receiving signals (Taborsky 1998), social structure and B I O D I V E R S I T A S 20 (4): 1133-1139, April 2019 1134 adaptation (Kim et al 2008), change strategies (Shaurabh et al 2013), rationalization of fishery catch in public waters (Suryaningsih et al 2014), and choice in parent fish for breeding (Esmaeili et al 2017), mate and intrasexual competition (Taborsky 1998). This study aims to determine the sexual dimorphism of M. singaringan based on morphometric characters.…”

Sexual dimorphism in the electric knifefish, Gymnorhamphichthys rondoni (Rhamphichthyidae: Gymnotiformes)

“…Dentition may also be sexually dimorphic, with differences between males and females in number, shape and arrangement of teeth (Gomes and Tomas 1991;Kajiura and Tricas 1996;Böhlke 1997;Rapp Py-Daniel and Cox Fernandes 2005;de Santana and Vari 2010). The shape of the urogenital papilla may also differ between males and females (Esmaeili et al 2017).…”