Lepidodesma aligera (Heude, 1877)

Wu, Ruiwen, Liu, Lili, Zhang, Liping, Jin, Dandong, Wu, Xiaoping, Liu, Xiongjun, Xie, Zhicai & Li, Zhengfei, 2024, Molecular phylogeny and comparative morphology reveal the species validity and systematic position of Lepidodesma (Bivalvia: Unionidae), Organisms Diversity & Evolution (New York, N. Y.) 24 (1), pp. 51-66 : 60

Species validity of Lepidodesma aligera

Soft-body features such as the form and size of papillae in the incurrent aperture, pigmentation in the excurrent aperture, etc., can be utilized for species delimitation and differentiation regardless of age or geographic origin ( Bespalaya et al., 2023; Klishko et al., 2014, 2017). Our findings reveal significant variations in the incurrent aperture, excurrent aperture, and gill between Lepidodesma aligera and Lepidodesma languilati . Furthermore, we also analyze the genetic variability in the mitochondrial barcode (COI) to enhance the validity of L. aligera as a distinct species. The average genetic distance between two species is determined to be 4.0%, which is consistent with the established threshold of 3% for defining distinct species ( Barrett & Hebert, 2005; Hebert et al., 2003). Moreover, the time-calibrated trees based on three molecular markers (COI, 16S rRNA, and 28S rRNA) elucidate that L. languilati collected from Jiangxi, Henan, and Hunan and L. aligera collected from Hunan congruently retrieved monophyletic, and the divergence between L. aligera and L. languilati occur during the middle of the Neogene (~ 12.94 Mya, 95% HPD= 6.72–22.13 Mya).

Integrative taxonomy approaches provide a viable solution to the ongoing debate surrounding morphological species definitions. In recent years, an increasing number of studies have employed integrative taxonomy to clarify the taxonomic validity of freshwater mussels ( Ayrat, 2005; Lopes-Lima et al., 2017a, 2018a; Malhotra & Thorpe, 2004; Prié & Puillandre, 2014; Sheth & Thaker, 2017). Previous studies have classified Lepidodesma aligera as a variant of Lepidodesma languilati , attributing potential morphological variations to specific habitats ( Heude , 1877; Paetel, 1890). Integrating morphological, anatomical, and molecular data, we strongly endorse the classification of L. aligera as a valid species. The well-developed post-dorsal wing with distributed nodules can serve as a diagnostic characteristic to distinguish both species rather than intraspecific variation characteristics.