RESUMO
The Tritoniidae provides one of the most famous model species for neurophysiology and behaviour, yet a well-developed phylogenetic framework for this family is still incomplete. In this study, we explored the species-level taxonomy, phylogenetic relationships, and geographic distributions of the tritoniid nudibranchs. During numerous expeditions, specimens from southern South America, Sub-Antarctic Islands, and Antarctica were collected, documented alive, and fixed for anatomical descriptions and genetic sequencing. DNA from 167 specimens were extracted and sequenced for mitochondrial (COI, 16S) and nuclear (H3) markers. An additional 109 sequences of all available tritoniids plus additional outgroups were downloaded from GenBank for comparative purposes. Maximum Likelihood under the GHOST model of evolution and Bayesian inference using the GTR + GAMMA model produced congruent topologies from concatenated alignments. The results of ABGD, GMYC, bPTP, and mPTP species delimitation analyses suggest many separately evolving units that do not coincide with traditionally recognized species limits. Southern Ocean Tritoniella and Tritonia species split into several previously unrecognized species. This result is in accordance with the limited dispersal abilities of some southern tritoniids. Along with the most complete phylogeny of Tritoniidae to date, we also provided many taxonomic notes at the species and genus level. Tritoniidae species are yet another example of under-recognized diversity in the Southern Ocean.
Assuntos
Gastrópodes , Filogenia , Animais , Regiões Antárticas , Teorema de Bayes , Gastrópodes/classificação , Gastrópodes/genética , América do SulRESUMO
Polyclads are a conspicuous group of marine invertebrates, the most charismatic members of the phylum Platyhelminthes. From Brazil, a total of 71 polyclad species were reported or described. Only three of them were recently described, five are recent records for the Brazilian coast, and 55 were described by Ernest and Eveline Marcus, who were by far the most productive workers. However, they quite often published in Portuguese or German, rather than English, and have not designated type material or specified material deposited in museum collections. Most of the polylcad material studied by the Marcus was found to be in the Swedish Museum of Natural History. Here we summarize the knowledge about Brazilian polyclad biodiversity, give information about deposited material in different museums for future reference, and designate type material for the species that did not have any. We examined 58 polyclad species reported from Brazil and designated type material and information available on type series of 52 species. Lectotypes (89 vouchers) were designated for 30 species and paralectotypes (73 specimens / 70 vouchers) were designated for 22 Brazilian species. Among the 261 type vouchers examined in this work, 22 species (77 vouchers) had material recognized as holotypes and 2 vouchers were recognized as paratypes. Of the total number of species reported from Brazil, 10 species remain without information about type material. In the present paper we also propose a new combination (Lurymare cynarium nov. comb.). Eleven species have their geographical distribution range broadened and 42 were photographed for the first time, five of those were photographed live as well. The number of Brazilian polyclad species is expected to rise when different regions and environments are surveyed.
Assuntos
Platelmintos , Animais , Biodiversidade , Brasil , MuseusRESUMO
Traditionally, species identification in nudibranch gastropods relies heavily on body color pattern. The Felimida clenchi species complex, a group of brightly colored Atlantic and Mediterranean species in the family Chromodorididae, has a history of exceptional controversy and discussion among taxonomists. The most widely accepted hypothesis is that the complex includes four species (Felimida clenchi, F. neona, F. binza and F. britoi), each with a characteristic body color pattern. In this study, we investigated the taxonomic value of coloration in the Felimida clenchi complex, using molecular phylogenetics, species-delimitation analyses (ABGD, GMYC, PTP), haplotype-network methods, and the anatomy of the reproductive system. None of our analyses recovered the traditional separation into four species. Our results indicated the existence of three species, a result inconsistent with previous taxonomic hypotheses. We distinguished an undescribed species of Felimida and redefined the concepts of F. clenchi and F. binza, both highly polychromatic species. For the first time, molecular data support the existence of extreme color polymorphism in chromatic nudibranch species, with direct implications for the taxonomy of the group and its diversity. The polychromatism observed in the F. clenchi complex apparently correlates with the regional occurrence of similar color patterns in congeneric species, suggesting different mimicry circles. This may represent a parallel in the marine environment to the mechanisms that play a major role in the diversification of color in terrestrial and fresh-water chromatic groups, such as heliconian butterflies.