Early embryonic development of brackish water Killifish Aphanius hormuzensis (Teleostei, Aphaniidae) inhabiting coastal environment in Southern Iran

Abstract

The embryonic and early developmental stages of Killifish Aphanius hormuzensis reared in a laboratory condition were investigated in detail using light microscopy. The adult male and female of A. hormuzensis were captured from the wild. They were kept in laboratory condition for 2 months and spontaneously spawned at 28 ± 1°C. The fertilized macrolecithal eggs were characterized with spherical shape, transparent and average 1.60 ± 0.20 mm in diameter. The embryonic development was started with fertilized egg activation and the first cleavage was observed in 2.5 hr ± 20 min post fertilization (hpf), followed by blastula formation and gastrulation stages in 7 and 11 hpf respectively. First somite was observed in 20 hpf and the heart beating was detected in 25 hpf. The early ontogeny of A. hormuzensis was followed by complements of organs formation and the newly hatched larva with 4.9 ± 0.10 mm in length was detected in 166 hpf. This study provides a basis for further research on reproductive biology, conservation and breeding of this species.

Life cell imaging microscopy of embryo and early development of the Kol tooth‐carp, Aphanius darabensis (Teleostei: Aphaniidae)

“…The studied Kol tooth‐carp embryogenesis highlighted the fact that the process of gastrulation requires dramatic cell movement in the form of epiboly and that the cells must involute to form mesoderm. The pattern which is almost similar to other studied fishes of the genus Aphanius, for example A. sophiae , A. farsicus , A. vladykovi and A. hormuzensis (Masoudi et al., 2018; Motamedi et al., 2019; Sanjarani Vahed et al., 2017a, 2017b; Sanjarani Vahed et al., 2018).…”

“…Similar to other studied fishes of the genus Aphanius (Masoudi et al., 2018; Sanjarani Vahed et al., 2017a, 2017b; Sanjarani Vahed et al., 2018; Motamedi et al., 2019), A. darabensis undergoes similar general stages of embryogenesis, that is the zygote, cleavage, blastula, gastrula, neurulation, segmentation and organogenesis before hatching. Mated pairs of A. darabensis spontaneously spawned in captivity in the laboratory condition at 24°±1°C laying eggs with diameters of 0.945–1.196 mm.…”

“…Fertilized eggs continue with meroblastic/radial cleavage consisting of six stages: 2, 4, 8, 16, 32 and 64‐cell stages. The cells divided synchronously at the animal pole during cleavage following the same pattern of cleavage observed in the other Aphanius species and other cyprinodontid fishes, that is Fundulus xenicus (see Koenig & Livingston, 1976; Masoudi et al., 2018; Motamedi et al., 2019; Sanjarani Vahed et al., 2017a, 2017b; Sanjarani Vahed et al., 2018). The first cleavage groove initiated from one side of the blastodisc, dividing the blastodisc into two approximately equal‐sized blastomeres.…”

“…2017b), 1.40 ± 0.02 mm ( n = 11) for A. farsicus (Sanjarani Vahed et al. 2017b), 1.09–1.77 mm in size ( n = 90) with mean of 1.45 ± 0.20 for A. sophiae (Masoudi et al., 2018) and 1.60 ± 0.20 mm in diameter ( n = 37) for A. hormuzensis (Motamedi et al., 2019). Based on the data from Kamal, Bakhtiyari, Abdoli, Eagderi, and Karami (2009), the mean diameter of mature eggs in A. sophiae (now = A. kavirensis ) from the Shour River of Namak Lake basin was 1.4 ± 0.19 mm with minimum and maximum diameters of 0.66 and 2.23 respectively.…”

“…There are currently about 41 valid species in the genus, most of them are found in central Anatolia and Iran (see Esmaeili et al, 2016; Fricke, Eschmeyer, & Van der Laan, 2020). Members of the genus Aphanius exhibit sexual dimorphism especially in colour pattern, have external fertilization and lay transparent eggs making them appropriate group for the embryological and developmental studies (Esmaeili, Masoudi, Ebrahimi, & Elmi, 2016; Masoudi, Esmaeili, & Ebrahimi, 2018; Sanjarani Vahed, Esmaeili, Masoudi, & Ebrahimi, 2017a; Sanjarani Vahed, Esmaeili, Masoudi & Ebrahimi 2017b; Motamedi, Teimori, Masoumi, Mohammadzadeh Shaghooei, & Mousavi, 2019). Moreover, these specialized small fishes are well adapted to live in extreme and harsh environmental conditions and have been found particularly interesting for evolutionary and speciation studies (Teimori, Esmaeili, Erpenbeck, & Reichenbacher, 2014).…”