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Previous studies demonstrated that nasolacrimal ducts were present in the ancestral plethodontid lineage. Two lineages within Plethodontidae contain individuals that do not possess nasolacrimal ducts: Desmognathus and Eurycea. Earlier works examined only two species of Desmognathus, D. fuscus and D. monticola. We obtained every Desmognathini (Phaeognathus + Desmognathus) species possible from novel collections and museum collections and assessed presence or absence of nasolacrimal ducts using contrast-enhanced computed tomography and routine histological procedures. The goal was to test the hypothesis that nasolacrimal ducts were lost on the evolutionary branch leading to Desmognathus. We rejected our hypothesis by finding that nasolacrimal ducts were absent in all Desmognathus that we examined and Phaeognathus hubrichti; thus, we recovered the absence of nasolacrimal ducts on the evolutionary branch leading to Desmognathini.

The taxonomy of the diminutive bolitoglossine salamanders of the subgenus Nanotriton has previously been a source of confusion among specialists. At various times, at least three different species of Nanotriton have been reported to occur in Honduras: Bolitoglossa nympha, B. occidentalis and B. rufescens. Phylogenetic analysis of 16S and cyt b from samples from three localities in Honduras (departments of Yoro, Copan and Cortes) confirms that most populations are assignable to B. nympha. Nine samples collected from a single locality on the northern slope of the Sierra de Omoa, between 120 and 190 m in elevation, were found to represent two distinct taxa: B. nympha and B. rufescens. Field examination of these nine specimens found them to be morphologically indistinguishable, including a lack of maxillary teeth in all specimens. As such, in situ identification of the two species in north-western Honduras is problematic given the occurrence of the two taxa in microsympatry in at least one locality. The discovery of yet another divergent lineage of B. rufescens highlights the need for a taxonomic reassessment within this species complex.

We have examined the morphology of the skeletal elements involved in constricted-based tail autotomy in Neotropical plethodontid salamanders of the genus Bolitoglossa. Observed variation in the transverse processes of the first caudal vertebra ranges from a relatively generalized condition, similar to that seen in North American species, to morphologically specialized structures found only in tropical species. Here we present evidence that most species of Bolitoglossa have evolved hypertrophied, reversed transverse processes whose shape and size go beyond what is necessary for structural support in constricted-based tail autotomy and allow the autotomized tail to be used as an anti-predator weapon. We discuss the evolutionary implications of this mechanism.

The diversity of the tropical climbing salamander genus Bolitoglossa (Magnadigita) in Honduras has been underestimated historically, with 11 new species having been described in the past quarter-century. Bolitoglossa celaque is known to occur in three disjunct mountain ranges across the Lenca Highlands region of southwestern Honduras, and previous studies have independently demonstrated differences in mitochondrial genealogy and genome size between populations to the east and west of the Mejocote–San Juan Depression. Sampling from all three mountain ranges represented two genetically distinct clades: one associated with the vicinity of the type locality, Montana de Celaque, and the second consisting of several eastern populations from the departments of Intibuca and La Paz. Distinctiveness of these two clades was further investigated and supported by analyses of morphological variation, geometric morphometrics of foot morphology, and comparative osteology. Based on congruent signals from each line of evidence, we restrict the taxon B. celaque to Montana de Celaque and describe the eastern populations as a new species of Bolitoglossa.

Genome sizes (expressed as C-values, or haploid genome sizes) of six species of Honduran plethodontid salamanders (one species of Nototriton and five of Bolitoglossa) vary greatly. Nototriton has a moderate-sized genome (29.2 pg) relative to other species of salamanders. Genome sizes in the species of Bolitoglossa span a range of 24 pg (∼23.4 gigabases) of DNA and include the largest genomes (83.7 pg) reported for the genus and for the family Plethodontidae. A phylogenetic analysis indicates that genome evolution in this group of salamanders featured mainly large increases in the mass of nuclear DNA. We propose that these evolutionary changes in genome size reflect random drift in small, isolated populations in the highlands of Central America.