Cryptic diversity across the Trans-Mexican Volcanic Belt of Mexico in the montane bunchgrass lizard Sceloporus subniger/ (Squamata: Phrynosomatidae).

Sceloporus subniger Poglaygen Smith is a montane bunchgrass lizard distributed across pine-oak forests of central Mexico. Prompted by the discovery of a new population of this lizard in far western Mexico, and by recent studies suggesting S. subniger may be a composite of several distinct species, we examined in more detail the genetic structure of S. subniger. We generated a mitochondrial DNA (mtDNA) dataset from 81 specimens and an ultraconserved elements (UCE) dataset representing thousands of genomic regions from 12 specimens to specifically evaluate the genetic distinctiveness of populations from western Michoacán and adjacent Jalisco along with the newly discovered population in the Sierra de Mascota in western Jalisco. We also recorded morphological data from 47 museum specimens to compare to our genetic data. Results from our analyses of the genetic data, augmented by specimen measurements and scale counts, support the notion that S. subniger is indeed a composite of distinct species. Montane bunchgrass lizards from western Michoacán and adjacent Jalisco, and from the Sierra de Mascota in western Jalisco, each represent distinct new species, which we describe and name here.

Combining ultraconserved elements and mtDNA data to uncover lineage diversity in a Mexican highland frog (Sarcohyla; Hylidae).

Molecular studies have uncovered significant diversity in the Mexican Highlands, leading to the description of many new endemic species. DNA approaches to this kind of species discovery have included both mitochondrial DNA (mtDNA) sequencing and multilocus genomic methods. While these marker types have often been pitted against one another, there are benefits to deploying them together, as linked mtDNA data can provide the bridge between uncovering lineages through rigorous multilocus genomic analysis and identifying lineages through comparison to existing mtDNA databases. Here, we apply one class of multilocus genomic marker, ultraconserved elements (UCEs), and linked mtDNA data to a species complex of frogs (Sarcohyla bistincta, Hylidae) found in the Mexican Highlands. We generated data from 1,891 UCEs, which contained 1,742 informative SNPs for S. bistincta and closely related species and captured mitochondrial genomes for most samples. Genetic analyses based on both whole loci and SNPs agree there are six to seven distinct lineages within what is currently described as S. bistincta. Phylogenies from UCEs and mtDNA mostly agreed in their topologies, and the few differences suggested a more complex evolutionary history of the mtDNA marker. Our study demonstrates that the Mexican Highlands still hold substantial undescribed diversity, making their conservation a particularly urgent goal. The Trans-Mexican Volcanic Range stands out as a significant geographic feature in Sarcohyla and may have acted as a dispersal corridor for S. bistincta to spread to the north. Combining multilocus genomic data with linked mtDNA data is a useful approach for identifying potential new species and associating them with already described taxa, which will be especially important in groups with undescribed subadult phenotypes and cryptic species.

Bimanual joint action: correlated timing or "bimanual" movements accomplished by two people.

A crew of two rowing together in perfect synchrony is an example of a task that requires each performer to maintain meticulous timing when coordinating their movements with the other. At the individual level, temporal coordination of the limbs has been observed in bimanual pointing movements even when made to targets of different distance. Timing of the arms is not independent; rather there is a natural temporal coupling. The aim of this experiment was to investigate whether the temporal characteristics of pointing movements can be observed under joint conditions. Sixteen pairs of participants made short and long, unimanual and bimanual pointing movements. In the unimanual and bimanual solo conditions, participants made the movements alone. In the joint condition, each participant contributed one arm to the joint "bimanual" movements. Absolute temporal coupling at movement initiation and termination was measured by the differences in reaction time and total response time. Relative temporal coupling at movement initiation and termination was measured by correlating reaction time and total response time of the left and right limbs. Pointing movements had synchronous movement termination in the bimanual solo conditions and asynchronous termination in the unimanual solo and bimanual joint conditions. The initiation and termination of the arms were not correlated in the unimanual solo condition (initiation r = 0.01, termination r = 0.03). Small-to-medium correlations (r = 0.19, r = 0.24) were observed in the bimanual joint condition, and they were larger than the unimanual solo condition (p = 0.022, p = 0.063). As expected, there were large correlations in the bimanual solo conditions (r = 0.91, r = 0.81). Our findings suggest that absolute temporal coupling does not occur between individuals, but there is evidence for relative temporal coupling in the bimanual joint condition.