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Open AccessArticle

Identification of Different Ecomorphotypes of Coilia nasus in the Dawanzhou Section of the Yangtze River

by Jiahao Liu, Tao Jiang, Junren Xue, Xiubao Chen, Hongbo Liu and Jian Yang

Fishes 2025, 10(3), 113; https://doi.org/10.3390/fishes10030113 - 5 Mar 2025

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X-ray electron probe microanalyzer technology was used to study the microchemistry and habitat history of Coilia nasus collected from the Dawanzhou section of the Yangtze River between May and June 2023. The Sr/Ca ratio from the otolith core to the otolith diameter was low (640–1100 µm), representing the first stage of development. In the second stage, C. nasus exhibited two distinct types. The first type, which included individuals 5HK05 and 6HK03, exclusively inhabited brackish estuarine waters. The second type, comprising 13 individuals, resided in higher-salinity seawater environments (Sr/Ca > 7). Furthermore, individuals 5HK01, 5HK03, 5HK07, and 6HK05 displayed a phase with a high Sr/Ca ratio compared to other fish. Freshwater coefficient analysis indicated that C. nasus in the Dawanzhou water area was unlikely to continue upstream to Dongting Lake in the middle reaches of the Yangtze River but may have entered Poyang Lake through its mouth or reproduced in its upper reaches. Analysis of sexual maturity and migration history suggested that the Dawanzhou section primarily serves as a migration channel for C. nasus, with a potential spawning ground for this high-value fish located nearby. Full article

(This article belongs to the Section Biology and Ecology)

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13 pages, 1529 KiB

Open AccessEditor’s ChoiceArticle

Bats of the Tunisian Desert: Preliminary Data Using Acoustic Identification and First Record of Taphozous nudiventris in the Country

by Ridha Dalhoumi, Ridha El Mokni, Ridha Ouni, Hamouda Beyrem and Stéphane Aulagnier

Diversity 2023, 15(11), 1108; https://doi.org/10.3390/d15111108 - 25 Oct 2023

Cited by 1 | Viewed by 2700

Abstract

Increasing aridity usually results in decreasing bat abundance and species richness, and the Saharan desert is an example of such impoverishment. Moreover, the harsh climatic and field conditions in this area restrict the feasibility of surveys. Therefore, the bat fauna of the Tunisian Sahara was unstudied until an expedition was conducted in May 2021. A total of seven species were recorded using passive bat detectors set mainly at water bodies, which concentrate bat activity. Echolocation calls of these species did not depart from published records for the Mediterranean area. Our data failed to identify the two ecomorphotypes of Pipistrellus kuhlii but confirmed the adaptability of this species to local conditions. For the first time in Tunisia, we recorded echolocation calls of Taphozous nudiventris, a species that has been rarely reported in North Africa. The highest species richness was identified at the largest wetlands of Oued Daghsen (Oued Dkouk Nature Reserve) and at Bordj el Khadra (only six and four species, respectively). Most Mediterranean species were recorded in the northern locality, while desert species were more active in the most southern one. The importance of water bodies for bats was confirmed once more. No sign of competition among species was detected, as the Mediterranean and desert-dwelling bat species were active at the same time. Additional surveys should be planned in order to enlarge the list of seven species recorded in only one week. Full article

(This article belongs to the Special Issue Key Aspects in the Ecology and Diversity of Desert-Dwelling Bats)

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14 pages, 2564 KiB

Open AccessArticle

The “True Colours” of Golden Loaches (Teleostei: Cobitidae)

by Jakub Fedorčák, Radek Šanda, Tihomir Stefanov, Jan Mendel, Michal Nowak, Peter Križek, Anabel Perdices, Jasna Vukić and Ján Koščo

Fishes 2023, 8(2), 119; https://doi.org/10.3390/fishes8020119 - 20 Feb 2023

Cited by 1 | Viewed by 2805

Abstract

Loaches of the genus Sabanejewia are model organisms for many ichthyologic studies focusing on morphological and colour variation. The bright lateral spots—a part of the mimicry of this fish—cause a taxonomic puzzle. Common practice is that morphometric and molecular studies lack habitat assessments of species originating from different environments. In this study, we analysed body shape and colour variation within two species of Sabanejewia in order to reveal whether they are more affected by phylogeny or environmental conditions. The environmental parameters were obtained using satellite mapping tools, body shape using geometric morphometry, and the molecular identification of specimens using an analysis of mitochondrial DNA (sequence of the cytochrome b gene). Generalized linear mixed models were used for the analysis of lateral spot numbers, and principal components analysis to describe the changes in landmark position defined by the permutation tests. Results show a significant impact of the locality elevation and specimen’s sex on the change of the body shape. We identified significant differences in the number of lateral spots, which are considered mimicry variation across an elevation gradient. Morphological differences of Sabanejewia spp. vary with ecological factors along the river continuum. Full article

(This article belongs to the Section Biology and Ecology)

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