A Salamander tale: Relative abundance, morphometrics and microhabitat of the critically endangered Mexican salamander Pseudoeurycea robertsi (Taylor, 1939)

Abstract

Roberts’ False Brook Salamander (Pseudoeurycea robertsi) is a critically endangered plethodontid salamander, endemic to the Nevado de Toluca Volcano (NTV), Mexico. Little is known about the biology and ecology of this species, including its microhabitats. Thus, this study aimed to collect basic information about P. robertsi. We sampled fourteen forested sites in the NTV; to corroborate the correct identification of the species we used genetic data, we assessed the variation in head morphometric measurements and dorsal colouration patterns amongst localities and the microhabitat features associated with P. robertsi presence. Of the four potential salamander species, P. robertsi was the most abundant (89.80%) and widely distributed (approximately within 130 km2) salamander in the NTV. We did not find significant variations in morphometry; however, we found significant differences in dorsal patterns between populations (in the number and size of segments of the dorsal stripe). The average total length for 185 adults was 89.15 mm (38.7–117.9 mm); we found seven patterns of dorsal stripe. We found 98% of P. robertsi individuals under the bark of fallen logs in Abies religiosa and A. religiosa-Pinus sp. forests, with a higher number of detected salamanders in naturally-fallen logs than in cut logs (34% vs. 10%). Thus, keeping well-preserved A. religiosa forests and retaining fallen logs is essential to P. robertsi conservation.

Genetic diversity and functional connectivity of a critically endangered salamander

“…We recommend prioritizing the areas of Amanalco, Meson Viejo, Rancho Viejo, and Raices in conservation programs, since these areas have high levels of genetic diversity, connectivity, and/ or numbers of individuals (Sunny, Domínguez-Vega et al, 2021).…”

“…To preserve the connectivity between P. robertsi populations, it is necessary to preserve all core areas regardless of size, as small patches can reduce isolation distances between larger patches (Fahrig, 2017(Fahrig, , 2020. Moreover, it is extremely important to retain old-growth Abies trees (Emel & Storfer, 2015;Spear & Storfer, 2008;Trumbo et al, 2013) and fallen logs (González-Fernandez et al, 2019;Sunny, Domínguez-Vega et al, 2021) as they provide moist shelters with different types of microhabitats (Emel & Storfer, 2015;…”

“…Pseudoeurycea robertsi is a forest specialist, which inhabits Abies-Pinus forest. It can be found under the bark of fallen logs, where it finds refuge and food (González-Fernández et al, 2019;Sunny, DomÍnguez-Vega et al, 2021). Despite this species is relatively abundant at certain well-preserved localities, there is evidence of a reduction in its abundance since 2003 (Bille, 2009).…”