Organisms Diversity & Evolution最新文献

Hybrid systems represent ‘new ecological opportunities’, as the changes in their vegetative and reproductive traits may facilitate colonization of new niches. The Cactaceae species Xiquexique gounellei and Xiquexique tuberculatus present different habitat preferences in the Brazilian Caatinga, however, across their distributions, some populations occur sympatrically and some individuals showed vegetative characteristics intermediate between these two species, suggesting a hybrid zone. These individuals also clearly did not belong to either of the two species, leading us to suppose that they could be hybrids, named as X. × heptagonus. Taking into account this assumption, we used a series of protocols to compare the floral attributes and signals, and floral biology displayed by the putative hybrid with those of its parents. The results showed that the flowers of the hybrid are morphologically intermediate to those of their parents. The colour of the external elements of the perianth is transgressive, and the white colour of the internal perianth-segments is shared between the three taxa. Scent analyses showed that X. × heptagonus has a scent profile that is intermediate to those of its parents, with only a few compounds indicating a transgressive phenotype. Both taxa of Xiquexique received visits from nectarivorous bats (Glossophaginae and Lonchophyllinae) and from the hawkmoths Agrius cingulata and Erinnyis ello. Our results reinforce the existence of this hybrid in the genus Xiquexique being derived from the possible parent species present. We also revealed how the floral morphology and the visual and olfactory cues of X. × heptagonus were shaped by the hybridization.

Recent surveys of Antarctic waters in the Terra Nova Bay (Ross Sea) revealed numerous bryozoan species including ctenostome bryozoans. Whereas cheilostome bryozoans are well-studied in these latitudes, ctenostomes remain highly neglected. Large ctenostomes are easily recognized by their lack of calcified skeletons, but this lack also renders them difficult and tedious to identify. As a result, histology and reconstructions of internal soft tissues are required to classify this group of bryozoans. Thanks to the availability of new specimens from Terra Nova Bay, a detailed analysis of growth form, gut morphology and tentacle number of two colonies, initially ascribed to the ctenostome bryozoan genus Alcyonidum Lamouroux, 1813, turned out to be a new species, Alcyonidium kuklinskii sp. nov., which we described in this study. These specimens were also barcoded (COI) and sequences compared to available ones. Together with the new species described here, a total of ten species of Alcyonidium is now known for the Southern Ocean, accounting for one eighth of the entire genus diversity. All Southern Ocean species appear to be endemic. In order to speed the identification of the Antarctic Alcyonidium species, we provide an identification key and a distribution map of all type species. In brief, colony morphology, zooidal size and, in particular tentacle number represent the most suitable characters for identifying species within this genus.

Increasingly sophisticated molecular techniques and research tools have greatly advanced the understanding of species diversity and phylogenetic relationships in freshwater mussels. However, malacologists have been puzzled by the taxonomic position and species validity of certain species, particularly those described solely based on conchological characteristics. The genus Lepidodesma is one such group. Here, we integrate shell morphology, soft-body anatomy, and molecular phylogeny to delimit the species validity of Lepidodesma aligera (Heude in Conchyliologie Fluviatile de la Provoince de Nanking 3:17–24, 1877) and Lepidodesma languilati (Heude in Journal De Conchyliologie 22:112–118, 1874). Comparative morphology reveals that L. aligera can be distinguished from L. languilati by its higher post-dorsal wing covered with scattered nodules, as well as differences in the incurrent aperture, excurrent aperture, and gill. Additionally, the average genetic distance based on DNA barcodes (COI) between both species is 4.0%. Integrative taxonomy supports the distinct species of L. aligera, rather than synonymy for L. languilati. Mitochondrial phylogenomic analyses confirm four monophyletic groups (Ambleminae + (Gonideinae + (Unioninae + Parreysiinae))) within the family Unionidae. L. aligera and L. languilati have a well-supported sister-group relationship and form a basal clade splitting from the rest of Unioninae. Therefore, the genus Lepidodesma should be classified as Lepidodesmini in Unioninae. The molecular clock with fossil calibration indicates that Lepidodesma originated in the Early Cretaceous (~121.30 Mya, 95% HPD = 90.37–156.54 Mya) and diverged in the Middle Neogene (~12.94 Mya, 95% HPD = 6.72–22.13 Mya). This study firstly provides anatomical features and molecular data for L. aligera and demonstrates the species validity and the systematic position of Lepidodesma taxa, which enrich our understanding of this rare group and facilitate its management and conservation.