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Parotocinclus adamanteus, new species, is described from a series of specimens collected in the upper portion of the Rio Paraguaçu basin, a coastal river within the Chapada Diamantina domain, a large plateau on the State of Bahia in northeastern Brazil. The description of this new species represents the first record of a member of the Hypoptopomatinae from this relictual area. The new species is diagnosed from other Parotocinclus by having a distinct rostral border forming a fleshy intumescence on the lateral portion of head ornamented with moderately hypertrophied odontodes in adult males. It is also diagnosed from congeners by a remarkable secondary sexual dimorphism in the shape of the pelvic fin, in which the branched rays of males decrease in size, resulting in a pointed posterior fin margin (branched pelvic-fin rays in females have approximately the same size, producing a round posterior fin margin). In addition, the new species can be further distinguished from other species of Parotocinclus by lacking a rostral plate covering the tip of the mesethmoid anteriorly, by lacking abdominal plates between the pectoral girdle and the anus, by having numerous premaxillary teeth (45–61), and by having a short and mesially expanded ventral portion of the cheek canal plate. Recent phylogenetic analysis indicates that Parotocinclus adamanteus, new species, is closely related to P. jequi, P. prata, and P. robustus.
Invasive species represent a major threat for biodiversity. The numbers of independent introductions, introduced propagules, and introduction episodes are critical aspects for invasion success. Here, we traced the source(s) of introduction and determined the historical route of invasion in order to understand the main stages of the invasion process. However, we often must rely on indirect information when studying invasive species (i.e., not knowing where the invasive population originated), hence requiring robust analytical methods to solve those questions. The invasive population of the snake Boa constrictor in the Mexican Caribbean (Cozumel Island) has been studied ecologically and genetically, but, despite several lines of evidence suggesting its invasive nature, a full account of its invasive history is lacking. Here, we aimed to reconstruct the boa's invasion history by deciphering the original source(s) of the Cozumel population, routes of invasion, likely number of propagules, and estimation of historical genetic and demographic parameters, based on a comprehensive set of analytical tools including tree topology-based methods and Approximate Bayesian Computational algorithms. The phylogenetic relationship of the Cozumel boa within the Boa constrictor complex was unknown; hence, to identify the source populations, we first needed to clarify its genealogical relationships. We used mitochondrial and nuclear sequences and nuclear microsatellites, together with the widest geographic sampling along the species' entire continental distribution. With our genetic approach, we demonstrate that the Cozumel population was derived from an admixture of individuals from different geographic localities. Moreover, our demography results allowed us to successfully confirm both anecdotal and previous genetic information, concordant with a scenario in which a likely small number of propagules were released on the island about 50 years ago. Notably, national law hinders the possibility of performing any control protocols for the boa, hence our results highlight a rather unique conservation paradox, where the Cozumel boa has a novel endangered protected species status as B. imperator, but it is also an invasive exotic predator threatening the critically endangered endemic and native biota of Cozumel. Therefore, any conservation decisions should consider that boas in Cozumel are invasive, opening the possibility to legally allow implementing control or eradication programs.
Amphibian life history strategies can vary across broad geographic patterns, which have been explained, at least in part, by how development, growth, maintenance, and reproduction respond to temperature. However, there is a dearth of information regarding life history traits and their variation among populations for many amphibian species, which prevents assessment of these broad patterns among species. Therefore, we used museum specimens to assess the variation in reproductive condition of Plethodon montanus across its range and used skeletochronology at five populations along an elevational gradient to determine the elevational variation in age, growth rate, and asymptotic size. We found that body size and temperature seasonality best explained the variation in the presence of eggs and a mental gland, whereas body size alone best explained the presence of enlarged pigmented testes. We also found that longevity in P. montanus is at least 12 years with higher elevations having a higher proportion of older individuals compared to lower elevations and that size was a better explanation of reproductive condition than age across the elevation. Our results further demonstrate the importance of body size for amphibian life history traits and the utility of museum specimens to estimate these traits. Variation in reproductive condition across the range of P. montanus is likely the result of variation in growing season length. Lastly, we found evidence suggesting asymptotic size and growth rates may have changed over the last half century, which would ultimately affect fertility and other life history traits and warrants future studies.
Lamniformes (Chondrichthyes: Elasmobranchii) is a group of sharks that consists of 15 extant species with a wide range of morphological diversity. The most rarely captured lamniform is Odontaspis noronhai, and many aspects of its biology remain unknown to date. In this study, the skeletal anatomy of a previously described specimen of O. noronhai was examined using computed tomography. The new skeletal data were then added to a previously published morphology-based character matrix to conduct a new phylogenetic analysis of the Lamniformes. Our phylogenetic study strongly suggests non-monophyly of Odontaspididae, that traditionally consisted of Carcharias taurus, O. ferox, and O. noronhai. Thus, the family Carchariidae is formally resurrected for the genus Carcharias to separate it from the family Odontaspididae sensu stricto for Odontaspis. The overall topology of our phylogenetic trees is similar to that of previously published morphology-based trees and drastically different from the tree topology generally attained by molecular data that cluster Alopias, Megachasma, Odontaspis, and Pseudocarcharias together as a separate clade. The major topological discrepancy between molecular and morphological trees may be attributed to unconventionally asynchronous rates between morphological and molecular evolution, at least in certain species within the Lamniformes, along with likely manifestation of mosaic evolution. The recognition of the family Carchariidae is important to conservation biology, because the extinction of C. taurus would not only mean the elimination of the genus Carcharias, but also the entire family Carchariidae. Our study demonstrates the importance of the integration of both morphological and molecular information to understand organismal evolution.