Testicular structure and spermatogenesis of the oviparous goodeids Crenichthys baileyi (Gilbert, 1893) and Empetrichthys latos Miller, 1948 (Teleostei, Cyprinodontiformes)

Abstract

The cyprinodontiform family Goodeidae comprises some 51 species, including subspecies, of freshwater fishes all of which are at risk or are extinct in the wild. It is classified in two allopatric subfamilies: the Goodeinae, endemic to the Mexican Plateau, and the Empetrichthyinae, known only from relict taxa in Nevada and southern California. The 41 species of goodeins are all viviparous and share a set of well-documented reproductive characters. In contrast, the recent species or subspecies of empetrichthyins are all oviparous and relatively poorly known, yet of critical interest in understanding the evolution of livebearing in the family. We previously described ovarian structure and oogenesis in empetrichthyins using archival museum specimens of females and here extend that study to males. Testicular characters of two species of empetrichthyins, Crenichthys baileyi, and Empetrichthys latos, are studied and compared directly with those of one species of viviparous goodeid, Ataeniobius toweri. The testis is a restricted spermatogonial type in both the Empetrichthyinae and the Goodeinae: spermatogonia are found solely at the distal termini of lobules, a diagnostic character of atherinomorph fishes. Morphology of the differentiation of germinal cells during spermatogenesis is similar in both subfamilies.In the oviparous C. baileyi and E. latos spermatozoa are free in the deferent ducts. In contrast, the spermatozoa of viviparous goodeids are organized into numerous bundles called spermatozeugmata, a characteristic of most fishes that practice internal fertilization. Differences between the goodeid subfamilies are interpreted relative to the oviparous versus viviparous modes of reproduction. Archival museum specimens are a reliable source of data on reproductive morphology, including histology, and may be the only specimens available of rare or extinct taxa. K E Y W O R D S archival museum specimens, atherinomorph testis, internal/external fertilization, sperm transfer mechanisms

Primary culture and endocrine functional analysis of Leydig cells in ducks (Anas platyrhynchos)

“…In poultry, collagenase II digestion combined with differential centrifugation was applied in the isolation of rooster LCs, and passage was used in its purification ( 34 ). The contradistinction in digestive enzyme selection is probably owing to the distinct concentration of connective tissues in viviparous and oviparous animals ( 41 ), in which potent trypsin could first digest the connective tissues in chicken testes and then released conglobate seminiferous tubule. In the present study, we undoubtedly followed the previous digestive enzyme selection procedure, accounting for the species similarity between chickens and ducks.…”

Reproduction of Lutjanus guttatus (Perciformes: Lutjanidae) captured in the Mexican Central Pacific

“…Sections were observed with a microscope (Primo Star, Zeiss) equipped with a digital camera (ERc 5s, Zeiss), and images and measurements of oocytes were obtained with the AxioVision program (V.4.8.2.0, Zeiss). The different oocyte phases were classified according to Yamamoto & Yamazaki (1961), Lucano-Ramírez et al (2001a), andBrown-Peterson et al (2011), and the testicle, according to the criteria of Lucano-Ramírez et al (2001b) and Uribe et al (2014Uribe et al ( , 2018.…”

“…The cellular organization is like in most teleosts, and the spermatogonia are located throughout the lobes. In addition, spermatogenic development within the cysts is synchronous, and lobes are found at different degrees of development (Grier 1981, Van Tienhoven 1983, Arellano-Martínez et al 2001, Uribe et al 2018. Several species of teleosts exhibit a lobe-type testicle; among these are L. peru (Lucano-Ramírez et al 2001b)…”

Does male gonopodial morphology affect male-female mating positioning in the livebearing fish Xenophallus umbratilis?

“…How copulation occurs in sexually reproducing organisms has garnered much attention, and this process is well documented in mammals [1][2][3], birds [4][5][6], reptiles [7][8][9], and some insects [10,11]. Copulation is not common in fishes, though internal fertilization is known to occur in sharks and rays [12], phallostethids [13], and goodeids [14], but is most often studied in the livebearing poeciliid fishes [15]. Despite a growing body of research in poeciliid fishes, our understanding of the mechanisms and behaviors associated with copulation in these species is incomplete.…”