Length-weight relationships were estimated for 24 freshwater fish species of Iran. Significant length-weight relationships with high correlation coefficient were found for all species. The value of the parameter b varied between 2.881 and 3.545.
To study scale based phylogenetic affinity, the ultrastructure and ornamentation characteristics of body key scales were studied for 12 gobiid species from the Iranian coast of the Persian Gulf including Qeshm and Hormuz Islands and the Makran coast of the Oman Sea using scanning electron microscopy (SEM) technique. The scales were removed from below the first dorsal fin, cleaned in potassium hydroxide solution 1%, and were prepared for the SEM imaging. The presence of both ctenoid and cycloid scales in the studied gobiids was revealed. The focus of ctenoid scales was positioned posteriorly, while the focus of cycloid scales was positioned in the postero-central part of the scale. In all the studied species, radii were located only on the anterior part of the scale, and the primary radii were dominant. Also, there were no granules in the inter circular space, but bifurcation was observed in some circuli.In most species, the teeth-like structures called lepidonts were present on the crest of circuli, which functionally help to firmly attach the scales to the epithelium. The dendrogram of the between-groups-linkage method sorted the gobiid species into the two main groups of five distinct clusters: (a) Cryptocentroides arabicus and Cryptocentrus cyanotaenia (the Cryptocentrus-lineage); (b) Bathygobius meggitti and Bathygobius cocosensis (the Glossogobius-lineage); (c) Coryogalops adamsoni and Coryogalops tessellatus (the Gobius-lineage); (d) Acentrogobius dayi, Istigobius ornatus,Favonigobius reichei, Aulopareia ocellata, and Silhouettea ghazalae (the Gobiopsis-lineage). It seems that the dendrogram topology obtained based on the macro-and microscopic structures of scales, reveals phylogenetic lineages of gobies that have already been proposed for these taxa. Hence, the results of this study are largely consistent with the previous molecular studies on the gobiid fishes and implied that besides other data, the analysis of scale shape and scale-surface microstructures could be served to study the diversification of gobiid species.
Pleistocene diversification and biogeographic barriers in southern Australia reflected in the phylogeography of a widespread and common lizard species. Molecular Phylogenetics and Evolution, 133, 107-119.
Translocation is among several tools available to conservation managers, either to augment existing populations, or to establish populations in previously occupied habitat, or in habitat identified as suitable for the future persistence of the species. Translocated reptiles do not always become established at the release site. We simulated a translocation site for an Endangered Australian skink, the pygmy bluetongue lizard Tiliqua adelaidensis, to investigate whether adding food would encourage released individuals to disperse less. We provided artificial burrows in a central release area within circular cages and found that lizards were more likely to remain in a burrow, spent less time exposed on the ground surface and were less likely to move out of the central area when food was provided. These modified behaviours are likely to encourage translocation success if lizards with added food expose themselves less frequently to predators, and if fewer of those lizards disperse away from the translocation site in the early days after release. We suggest that the provision of supplementary food will be an important component of any translocation programme for this lizard.
The embryonic and early larval development of laboratory reared Zagros tooth-carp, Aphanius vladykovi Coad, 1988, are described and illustrated. Development and embryogenesis start with the external fertilization of sticky, transparent and spherical telolecithal/macrolecithal eggs with a mean diameter of 1.61± 0.12 mm and it continues with meroblastic/radial cleavage, blastulation/blastula formation, epibolic cell migration during gastrulation and organogenesis resulting in a newly hatched larvae of 5.23 ± 0.09 mm in length with attached yolk sac at about 164 hr (at 24 ± 1°C) after fertilization.
Summary
Understanding embryonic development and ontogeny of species is a crucial part of any further biology, ecology and conservation studies. The present study describes the first detailed normal embryonic development of a tooth‐carp, Aphanius sophiae (Heckel, 1847), from fertilization to post‐ hatching. Aphanius sophiae spontaneously spawned at 24 ± 1°C. The newly laid eggs were transparent and spherical (1.45 ± 0.20 mm). We documented developmental times at 24 ± 1°C to egg activation (0.5 hr), cleavage (3 hr), blastula (10 hr), gastrula (20 hr), neurula (24 hr), somite (28 hr), turnover (60 hr), blood circulation (70 hr) and hatching (330 hr). This study contributes to a further understanding of the embryology and the early ontogeny of A. sophiae and may help improve the culture of other threatened species of the genus Aphanius.
Context
The use of artificial refuges is a common strategy for the conservation management of endangered species. However, artificial refuges may alter an animal’s natural behaviour that in turn may be detrimental to the species. The endangered pygmy bluetongue lizard from Australia is one species that will accept artificial burrows.
Aims
The aim of the present research was to determine whether the normal behaviour of the pygmy bluetongue lizards differed between artificial and natural burrows, so as to determine whether the existing artificial burrow is an optimal design for this species.
Methods
In the present study, we filmed the behaviour of lizards as they entered artificial and natural burrows. We compared the number of times a lizard entered a burrow, the time that lizards spent inspecting burrows, and the behaviours that lizards used when entering artificial and natural burrows.
Key results
We found that in natural burrows, lizards always entered head first, and then usually reversed direction inside, using an enlarged basal chamber, to sit with their head uppermost in the entrance. In artificial burrows, however, lizards had to enter head first, then reverse tail-first back out, and then reverse tail-first back into the burrow (so as to have their head facing upwards) We called this behaviour reversing from outside.
Key conclusion
The stereotyped reversing-from-outside behaviour when entering artificial burrows, and its occasional occurrence in natural burrows, suggest that it has evolved to allow lizards to use narrow burrows as well as those with a chamber, even though it can increase lizard’s surface activity and exposure to predation.
Implication
The reversing behaviour from outside the artificial burrow increases exposure to potential predators, and our observations suggest that a re-design of artificial burrows to incorporate internal space for turning around may improve their effectiveness in conservation management interventions.
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