Ultrastructure of spermatozoa of scolecophidian snakes (Lepidosauria, Squamata)

Abstract

Tavares-Bastos, L., Cunha, L.D., Colli, G.R. and Báo, S.N. 2007. Ultrastructure of spermatozoa of scolecophidian snakes (Lepidosauria, Squamata). -Acta Zoologica (Stockholm) 88 : [189][190][191][192][193][194][195][196][197] We provide a detailed description of the sperm ultrastructure of three species of scolecophidian snakes, Leptotyphlops koppesi (Leptotyphlopidae), Typhlops reticulatus (Typhlopidae) and Liotyphlops beui (Anomalepididae), and make comparisons with the spermatozoa of Ramphotyphlops waitii (Typhlopidae) (Harding et al. 1995). All the species studied bear synapomorphies of Squamata and Serpentes. Among scolecophidian snakes, we identified eight polymorphic characters. Previous analyses of molecular and somatic morphological data provide equivocal solutions to the relationships among Anomalepididae, Leptotyphlopidae and Typhlopidae. A close relationship between Anomalepididae and Typhlopidae is corroborated by two characters of sperm ultrastructure, presence of an electron-dense structure inside the proximal centriole and rounded mitochondria in transverse sections of T. reticulatus , Li. beui and R. waitii , whereas the absence of the ridge on the acrosome surface of Le. koppesi and T. reticulatus support a closer relationship between Typhlopidae and Leptotyphlopidae. The differences observed in sperm ultrastructure within Typhlopidae suggest the existence of snake intrafamilial polymorphism. The sperm characters of blindsnakes contain significant phylogenetic information and may provide important data for snake phylogenetic reconstructions.

Ultrastructural study of spermiogenesis in the Jamaican Gray Anole, Anolis lineatopus (Reptilia: Polychrotidae)

“…A single perforatorium within the subacrosomal space has been described as unique for squamates (Teixeira et al. 1999a,c; Tavares‐Bastos et al. 2007; Tourmente et al.…”

Ultrastructure of spermiogenesis in the Cottonmouth, Agkistrodon piscivorus (Squamata: Viperidae: Crotalinae)

“…As early elongation begins in Agkistrodon piscivorus, it becomes apparent that the acrosome complex is highly compartmentalized, which is common in most squamates (Healy and Jamieson, 1994;Harding et al, 1995;Jamieson and Scheltinga, 1994;Jamieson et al, 1996;Tavares et al, 2007). This complex compartmentalization has been suggested to aid in the release of hydrolytic enzymes that penetrate the outer layers of the ovum during fertilization (Talbot, 1991).…”

Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). VII. spermatozoon morphology and evolutionary trends of sperm characters in snakes

“…Since the first ultrastructural description of a snake spermatozoon by Furieri (1965), multiple studies have been conducted to determine the cytological similarities and differences of the spermatozoa within Serpentes (References in Cunha et al 2008 andTavares-Bastos et al 2008). Only a handful of these studies have attempted to put these data into a phylogenetic context; Tavares-Bastos et al Õs (2008) is the most recent study to map snake sperm traits (Jamieson and Koehler 1994;Harding et al 1995;Jamieson 1995;Jamieson 1999;Oliver et al 1996;Tourmente et al 2006;Tavares-Bastos et al 2007. Tavares-Bastos et al (2008) concluded that multiple characters such as a dense collar in the neck region and mitochondria shape as sinuous tubes in oblique section are proposed synapomorphies in Serpentes, and the ultrastructural data provided by Cunha et al (2008) and Tourmente et al (2008) corroborated these findings.…”