Kalthoff, Daniela C.Fejfar, OldrichKimura, YuriBailey, Bruce E....
20页
查看更多>>摘要：The lower incisor enamel microstructure of the fossil rodent family Eomyidae was believed to be three-layered and highly derived but rather uniform throughout the clade. Here, we describe a new four-layered schmelzmuster in Eomyidae consisting of a three-fold portio interna with longitudinal oriented, uniserial Hunter-Schreger bands and a one-fold portio externa, accounting for a unique enamel microstructure character combination in Rodentia. This new schmelzmuster type has developed early in eomyid evolution and is detectable already in the late Eocene (Chadronian) of North America. In European eomyids, it first occurs in the early Miocene (MN 3), implying that this four-layered schmelzmuster was not present in all members of the family but restricted to species included in Eomyini and some genera currently considered Eomyidae incertae sedis within Eomyidae. Additionally, our analysis recognizes three taxa with schmelzmuster divergent from all other eomyids. Incisor enamel microstructure does not advocate a close phylogenetic relationship of Eomyidae to either fossil or extant Heteromyidae and Geomyidae, nor to fossil Heliscomyidae and Florentiamyidae. Our results rather support the view that Eomyidae are placed outside Geomorpha.
查看更多>>摘要：Closely related bird species often exhibit elevated differentiation in the Z-chromosome. Genetic differentiation is repeatedly found in so-called 'islands of differentiation' that might contain loci under selection that contribute to reproductive isolation. Using double-digest restriction-associated DNA sequencing (ddRAD-seq), we examined genomic divergence of Mallard (Anas platyrhynchos) and Chinese Spot-billed Duck (A. zonorhyncha), two closely related species of ducks that occasionally hybridize. The taxa were distinguishable based on overall ddRAD-seq allele frequency differences. However, differentiation on the Z-chromosome was about 4.5 times greater than observed for autosomal DNA and included three fixed differences in SNPs. These SNPs are the first species-specific molecular markers revealed among mallard group species. The causes of elevated Z-chromosome divergence are discussed, including the possibility that Z-linked loci are resistant to introgression and potentially linked to phenotypic differences between the species.
Costa, Joao C. L.Graboski, RobertaGrazziotin, Felipe G.Zaher, Hussam...
19页
查看更多>>摘要：Within the diverse subfamily Dipsadinae, Imantodini represents one of the few groups distributed in North, Central and South America. The tribe comprises the genera Leptodeira and Imantodes, from which Leptodeira is the most diverse, including 15 species and 11 subspecies, distributed from southern USA to central Argentina. Taxonomy and affinities among these taxa are poorly resolved, and the phylogenetic relationships among the South American diversity were never properly assessed before. Here, we investigate the phylogenetic relationships and the taxonomic status of Leptodeira spp. based on a comprehensive multilocus dataset with emphasis in the South American radiation. Besides assessing the phylogenetic relationship and species cohesion, we also evaluate the morphological variation among the South American diversity of Leptodeira. Our results support the monophyly of Imatodini and Leptodeira, while indicating that several individuals classified as Leptodeira annulata and L. septentrionalis do not cluster together within their respective species. Moreover, specimens identified as belonging to the subspecies L. a. annulata, L. a. cussiliris, L. s. ornata and L. s. polysticta do not group together suggesting the current classification includes non-natural groups. The analysis of morphological evidence also supports the phylogenetics results, indicating that several clades can be recognized as evolutionary units presenting distinct phenotypes. To equate the taxonomy to our results, we propose a new taxonomic arrangement for Leptodeira in which we are: (1) redefining the composition of L. annulata and L. septentrionalis; (2) elevating five subspecies to species level; (3) revalidating one species; (4) recognizing four species complexes; and (5) indicating the presence of hidden diversity (probably four undescribed species). Finally, we describe a new species (Leptodeira tarairiu sp. nov.) from the open formations of South America (Cerrado and Caatinga), and we provide detailed redescriptions for all South American species of Leptodeira.
查看更多>>摘要：Anablepsoides is a widely distributed Neotropical killifish genus found in shallow streams, in both dense forests and open areas, throughout northern and northeastern South America. The phylogenetic and biogeographic relationships of the genus are here analysed, based on two nuclear and four mitochondrial genes of 26 species and six out-groups. The origin of Anablepsoides was recovered in Early Miocene in an area corresponding to the Paleo-Amazon-Orinoco system. The current analyses indicate that the initial diversification of the genus in two main clades was associated with marine transgressions related to the formation of the Pebas mega-wetland isolating each MRCA of those main clades in the upper Amazon river basin and river basins of the Guiana Shield. The diversification of the genus and the colonisation of new areas may be associated with Miocene and Pliocene events such as changes in the sea level, formation and extinction of wetlands, rupture of the Purus arch and Amazon river assuming the current flow to the East. Also, the evolution of Anablepsoides could be associated with the diversification of several other Neotropical lineages, so that the present study leads to a better understanding of the evolution of the Neotropical freshwater biota and South American geological history.
Paz-Sedano, SofiaMartin Alvarez, Jose FranciscoGosliner, Terrence M.Pola, Marta...
13页
查看更多>>摘要：Trapania is the second largest genus belonging to the family Goniodorididae, of which most of the species are reported from Indo-Pacific waters. To date, there are nine species of Trapania distributed along the temperate coasts of the East Atlantic Ocean and Mediterranean Sea: Trapania fusca, Trapania graeffei, Trapania hispalensis, Trapania lineata, Trapania maculata, Trapania orteai, Trapania pallida, Trapania sanctipetrensis and Trapania tartanella. However, the validity of some of these species has been problematic due to uncertain taxonomic characteristics used for the differentiation of the species. The genus Trapania has a very uniformly external morphology and very similar internal anatomy. As a consequence, the features most commonly used to differentiate species have been the colour pattern of the body and the morphology of the radula. In the present study, we perform a morphological and molecular revision of the East Atlantic-Mediterranean species of the genus Trapania. Morphological analyses include dissections and scanning electron microscope photographs of radulae, labial cuticles and penises. Molecular work includes phylogenetic, species delimitation and haplotype network analyses. Our results bring doubt on the taxonomic characteristics used so far, suggesting that the richness of the North Eastern Atlantic-Mediterranean species has been overestimated. Trapania hispalensis, T. lineata and T. pallida are shown to belong to the same taxa, with Trapania lineata as senior synonym.
查看更多>>摘要：Cumaceans are small peracarid crustaceans that can be remarkably diverse and important benthic organisms. Despite their ubiquitous presence in soft sediments, no well-resolved phylogeny currently exists, which impedes ecological and evolutionary studies of the group. We present a phylogeny based on Bayesian inference of six markers (18S, 28S, 12S, 16S, CytB and COI), which recovers monophyly of the order, a deep split between telson and pleotelson bearing groups, and monophyly of four of the seven included families, including monophyletic Pseudocumatidae, Lampropidae, Bodotriidae and Nannastacidae. The only species representing the family Gynodiastylidae in our dataset was positioned among members of Diastylidae in the phylogenetic analyses. However, this result is based on a single partial COI sequence; thus, we consider it doubtful, and the family Diastylidae are otherwise recovered as a monophyletic family. The family Leuconidae is split into two well-supported clades, a clade containing Antarctic members of the genus Leucon and a separate clade containing non-Antarctic members of the genera Leucon and Eudorella. The phylogeny is a great stride forwards, as it supports most families as monophyletic, making generic level phylogenies a plausible endeavour in the future.
NSTL
Wiley