Description
Pseudoeurycea granitum is a slender, moderately-sized Plethodontid salamander that has a snout-vent length of approximately 34.3 – 43.5 mm in males and 37.3 – 50.2 mm in females. The head of P. granitum is barely wider than its body, and it’s about 1.5 longer than it is wide. None of the features of P. granitum’s head are exceptionally discernible; the eyes do not extend past the jaw when viewed from above, as they are hardly protuberant. The mouth is rounded and blunt when viewed from the side, and the snout protrudes slightly over the mandible. In the submandibular region, males have oval-shaped mental glands that are visible but not protuberant. The nares are oval-shaped and inconspicuous due to their small size. The nasolabial grooves are weakly developed on females, but are blunt and well-developed for male specimens. The interorbital distance is approximately one-third of the width of the head. The neck is clearly defined from both the head and the body. Both forelimbs and hindlimbs are relatively short. The combined lengths of the forelimbs and hindlimbs are about half as long as the snout-vent length. When the limbs are adpressed along the trunk of the body, the limbs are separated by two intercostal spaces. This species has four long, slender digits on the forelimbs, and their relative lengths are as follows: III > II > IV > I. There are five similarly slender digits on the hindlimbs, with relative lengths of III > IV > II > V > I. All digits have blunt tips with visible subterminal pads. There is some limited webbing on the foot, which only extends to the base of the third toe. The tail is notably longer than the body, twice as long as the axilla-groin length and four times as long as the head length. The tail is rectangular around its base, but it becomes more rounded and tapers in size as you move toward the end (García-Bañuelos et al. 2020).

According to analysis of mtDNA, the groups most closely related to P. granitum include P. firscheini, P. leprosa, P. lynchi, and P. nigromaculata. However, these species have detectable differences in their color patterns and morphology, specifically regarding the interorbital bar. Pseudoeurycea firscheini, the species most closely related to P. granitum, is gray-brown in color and has a shorter tail and narrower head. Pseudoeurycea firscheini also lacks the black spots and yellowish coloring that is seen in P. granitum. Pseudoeurycea leprosa is a dark grayish-brown, is notably larger than P. granitum, and has no yellow coloring anywhere on its body. Pseudoeurycea lynchi is greenish-yellow with black spots over its entire body and tail, while P. granitum only has this yellow coloring on its tail and posterior dorsum with paler blotches or specks. Similarly, P. nigromaculata has a reddish-brown tail, making its coloring distinct from both of the previously mentioned species. Pseudoeurycea granitum specimens are smaller than both P. nigromaculata and P. lynchi, regardless of sex. Lastly, Pseudoeurycea granitum has a white or brown interorbital bar that extends between its eyelids; this feature is absent in any of the other aforementioned Pseudoeurycea species (García-Bañuelos et al. 2020).

In life, Pseudoeurycea granitum is brown with small black and white speckles from its head to its forelimbs. There is a brown or white interorbital bar that extends between the two eyelids. The dorsal surface between the shoulders and the base of the tail is yellowish-green with yellow speckles and black blotches. The dorsal surface of the tail, as well as the dorsal surface of all limbs, is also yellowish-green and has black spots. The sides of P. granitum are black with lichen-like light green blotches. On the gular surface, it is light gray, and the ventral surface of this species is black with light green and white speckles. The underside of hands and feet are light gray and the eyes are golden. In preservation, P. granitum is various shades of gray. The dorsal surface is medium gray with light spots, and the tail has dark gray splotches. The interorbital bar is a medium gray. The flanks and the ventral surface are dark gray with a variety of lighter spotting or mottling. The ventral side of the tail is medium gray, but it becomes more yellow toward the end (García-Bañuelos et al. 2020).

The variation between male and female Pseudoeurycea granitum individuals is most visible in certain physical characteristics. Males have well-developed, blunt nasolabial grooves and visible mental glands; females have poorly-developed nasolabial grooves and no mental glands, as mental glands are a secondary sex characteristic exclusive to males. The amount of spotting on the ventral surface and chin varies between each P. granitum individual. Additionally, the size and color of the interorbital bar varies by individual. The colors of the interorbital bar can range from white to yellowish-green, and it can be as wide as the eyelid or so thin that it cannot be easily seen (García-Bañuelos et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

View distribution map in BerkeleyMapper.

Pseudoeurycea granitum is found exclusively in central Veracruz, Mexico, specifically in Tepexilotla, Cerro Petlalcala, and Mundo Nuevo. These localities are less than 30 kilometers apart, and extensive surveys indicate that P. granitum has a very limited distribution. However, more surveys are needed in Puebla and Oaxaca -- two areas with similar environmental conditions -- to confirm this. They are found in cloud forests and pine-oak forests at elevations between 1,550 and 2,550 meters above sea level (García-Bañuelos et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
All collected Pseudoeurycea granitum specimens are found in trees or plants between 1 and 5 meters above the ground. The specimens were typically inactive and were found at various times throughout the year. Often, the specimens were found near agricultural sites, such as plantations or cattle fields. While some specimens were found under rocks or in the shade, most of the specimens were collected from bromeliads, or large flowering plants native to Mexico. In general, P. granitum prefers shady, wooded areas with plenty of flora (García-Bañuelos et al. 2020).

Pseudoeurycea granitum females likely lay eggs during the first months of the year -- much like their close relatives -- but this has not been shown for certain. Further surveys must be conducted to verify their reproductive patterns (García-Bañuelos et al. 2020).

Pseudoeurycea granitum is sympatric with P. firscheini in Cerro Petlalcala. More surveys must be conducted to determine if it overlaps in range with other Pseudoeurycea species (García-Bañuelos et al. 2020).

Despite extensive searches around the state of Veracruz, there have been very few Pseudoeurycea granitum individuals found. Because of their limited sightings and observations, this species is likely rare. To confirm this, more surveys are needed at different points during the year (García-Bañuelos et al. 2020).

While there is no explicit mention of what Pseudoeurycea granitum salamanders eat, they are prey animals to snakes. This is evidenced by one of the collected specimens that was regurgitated by a Thamnophis sumichrasti (García-Bañuelos et al. 2020).

Trends and Threats
Pseudoeurycea granitum is primarily found in the Mexican state of Veracruz, which has one of the highest rates of deforestation in the world. Thus the largest threat to P. granitum is habitat destruction. Some of the forests where the original P. granitum specimens were collected have since been cut down. One potential hope for this species’ conservation is the fact that they thrive on and around coffee plantations; these are less likely to be removed than forests and could provide a stable habitat for P. granitum. Additionally, while P. granitum can be found in reserves throughout Veracruz, these reserves are not always reliably and consistently managed, and this land is already limited. Improved resource management, both in forests and on plantations, is necessary for the survival of P. granitum (García-Bañuelos et al. 2020).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Urbanization

Comments
The species authority is: García-Bañuelos, P., Aguilar-López, J.L., Kelly-Hernández, A., Vásquez-Cruz, V., Pineda, E., and Rovito, S.M. (2020). “A New Species of Pseudoeurycea (Amphibia: Caudata) from the Mountains of Central Veracruz, Mexico.” Journal of Herpetology, 54(2) : 258-267

Pseudoeurycea granitum is a member of the Pseudoeurycea leprosa subclade. To determine the genetic relationship between P. granitum and other Pseudoeurycea species, researchers analyzed 16S mtDNA with a fragment of cytochrome b using Maximum Likelihood Method and a Bayesian phylogenetic analysis. From this, they found that P. granitum is sister to the clade containing P. firscheini and P. nigromaculata. The clade form by these three species are sister to P. lynchi and the next most closely related species is P. leprosa (García-Bañuelos et al. 2020).

The species name, “granitum”, is the Latin word for “granite.” Pseudoeurycea granitum resembles granite because of its multicolored speckles and splotches (García-Bañuelos et al. 2020).

When conducting field surveys, one salamander specimen was found when its body was regurgitated by a snake (Thamnophis sumichrasti) (García-Bañuelos et al. 2020).

References

García-Bañuelos, P., Aguilar-López, J.L., Kelly-Hernández, A., Vásquez-Cruz, V., Pineda, E., and Rovito, S.M. (2020). ''A New Species of Pseudoeurycea (Amphibia: Caudata) from the Mountains of Central Veracruz, Mexico.'' Journal of Herpetology, 54(2), 258-267. [link]

Species Account Citation: AmphibiaWeb 2020 Pseudoeurycea granitum: English name: Granite-colored salamander; Spanish name: Salamandra de color granito <https://amphibiaweb.org/species/9236> University of California, Berkeley, CA, USA. Accessed Apr 19, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Apr 2024.

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