2023-04-24, Grünwald, Christoph I., Montaño-Ruvalcaba, Carlos, Jones, Jason M., Ahumada-Carrillo, Iván, Grünwald, André J., Zheng, Jiacheng, Strickland, Jason L., Reyes Velasco, Jacobo

We describe a new species of Eleutherodactylus (subgenus Syrrhophus) from Guerrero, Mexico, based on morphological and molecular data, as well as advertisement call analysis. Eleutherodactylus franzi sp. nov. has unique features including widely expanded fingertips, indistinct, but visible lumbo-inguinal glands, an immaculate white venter and dark reticulations on a cream dorsal background colouration. The new species belongs to the Eleutherodactylus nitidus species group. Eleutherodactylus franzi sp. nov. is micro-endemic, restricted to a small range in karstic hillsides on the southern extreme of the Mexican Transverse Ranges. We discuss conservation needs of this species, which we provisionally classify as Critically Endangered.

2022-02-02, Reyes Velasco, Jacobo, Cox, Christian L., Jones, Jason Michael, Borja, Miguel, Campbell, Jonathan A.

Members of the Crotalus durissus species group are amongst the largest species of rattlesnakes and are of strong medical importance. The taxonomy of the group is convoluted, and the line of what is considered a species, subspecies or populations is hard to define. A recent study split one of the members of the group (C. culminatus) into three species, the nominal species, as well as C. ehecatl and C. mictlantecuhtli, based on genetic and morphological data. Here we reanalyze previously published mitochondrial and nuclear data, as well as additional sequences for two mitochondrial genes from members of the Crotalus durissus group, to test if isolation by distance (and not speciation) could be responsible for the genetic variation observed in previous studies. Our results show that the genetic differences between some of the species in the group (Crotalus simus – C. durissus and C. culminatus – C. ehecatl) are lower than intra-specific genetic distances. The only nuclear gene at hand for the C. durissus group (oocyte maturation factor Mos, c-mos) is not phylogenetically informative and cannot distinguish between many of the species in the genus, thus it is of little support when it comes to taxonomic decisions. We find low divergence at the mitochondrial level between these two species pairs, and at least in one of the species pairs we find a pattern of isolation-by-distance (IBD). Additionally, we performed a newly developed species delimitation analysis, DELINEATE, which supports the validity of C. mictlantecuhtli, but not C. ehecatl. These results suggest that the molecular differences at the mitochondrial level in members of the Crotalus durissus species group could be the result of IBD and not necessarily due to speciation events. We believe that additional sampling as well as additional molecular data is necessary to clarify species limits in the Crotalus durissus species group.

2022-11-08, Goutte, Sandra, Reyes Velasco, Jacobo, Kassie, Abeje, Boissinot, Stéphane

Frogs of the genus Leptopelis have diversified in the Ethiopian Highlands to occupy forests and montane grasslands both east and west of the Great Rift Valley. Genetic studies revealed that the endemic species Leptopelis gramineus (Boulenger, 1898) comprises multiple unnamed taxa. A careful examination of historical type specimens is, however, needed to fully resolve the taxonomy of the group. Here we use mitochondrial DNA and morphological analyses on a large sample of recently-collected Ethiopian Leptopelis , as well as century-old type specimens to demonstrate that the recently resurrected L. montanus Tiutenko & Zinenko, 2021 (previously Pseudocassina ocellata Ahl, 1924) is a junior synonym of L. rugosus (Ahl, 1924) and corresponds to the taxon found west of the Great Rift Valley, not east as previously thought. Our results show that populations inhabiting the mountains and plateaus east of the Rift constitute a distinct and undescribed species. We provide a re-description of L. rugosus and describe two new species inhabiting the Highlands east of the Great Rift Valley. We provide an identification key, as well as a description of the calls of the members of the Leptopelis gramineus species complex.

2022-01-01, Ahumada-Carrillo, Iván Trinidad, Grünwald, Christoph Imre, Reyes Velasco, Jacobo, Jones, Jason M.

2022-05-11, Torres-Dowdall, Julián, Rometsch, Sina J., Reyes Velasco, Jacobo, Aguilera, Gastón, Kautt, Andreas F., Goyenola, Guillermo, Petry, Ana C., Deprá, Gabriel C., da Graça, Weferson J., Meyer, Axel

Phylogenetic comparative studies suggest that the direction of deviation from bilateral symmetry (sidedness) might evolve through genetic assimilation; however, the changes in sidedness inheritance remain largely unknown. We investigated the evolution of genital asymmetry in fish of the family Anablepidae, in which males' intromittent organ (the gonopodium, a modified anal fin) bends asymmetrically to the left or the right. In most species, males show a 1 : 1 ratio of left-to-right-sided gonopodia. However, we found that in three species left-sided males are significantly more abundant than right-sided ones. We mapped sidedness onto a new molecular phylogeny, finding that this left-sided bias likely evolved independently three times. Our breeding experiment in a species with an excess of left-sided males showed that sires produced more left-sided offspring independently of their own sidedness. We propose that sidedness might be inherited as a threshold trait, with different thresholds across species. This resolves the apparent paradox that, while there is evidence for the evolution of sidedness, commonly there is a lack of support for its heritability and no response to artificial selection. Focusing on the heritability of the left : right ratio of offspring, rather than on individual sidedness, is key for understanding how the direction of asymmetry becomes genetically assimilated.

2021-02-11, Goutte, Sandra, Reyes Velasco, Jacobo, Freilich, Xenia, Kassie, Abeje, Boissinot, Stephane

Frogs of the genus Ptychadena that inhabit the Ethiopian highlands serve as a model system to understand biogeography, diversification, and adaptations to high elevations. Despite recent studies focusing on the systematics of this group, the taxonomy of the Ptychadena neumanni species complex remains only partially resolved, owing largely to the morphological resemblance of its members. Here, the taxonomy of this historically problematic group of frogs is revised by integrating morphological and molecular analyses on both century-old type specimens and more recently collected material. Based on these multiple lines of evidence, the P. neumanni species complex is shown to be more speciose than previously thought and four new species are described. With the aim of clarifying and stabilizing the taxonomy of the group, six species are also re-described and morphological and acoustic identification keys are provided. This study also establishes species distribution maps and reveals important differences in range size between the members of the P. neumanni complex, calling for adapted conservation measures across the Ethiopian highlands.