Description
Eleutherodactylus grunwaldi is a relatively large frog described from nine mature male specimens and one unsexed adult, but no known females. Adult male E. grunwaldi measure 28.4 - 32.4 mm from their snout to their vent. They have heads that are slightly less wide than they are long. When looking from the dorsal view, the snout appears truncated and angular, and when looking from the lateral view, the head tapers to a point and the lip has a slight flare to it. Males have vocal slits. Their tympanum is rounded and ranges from small to medium-sized with a width that is consistently 40 - 50% of the width of the eye, never reaching over 50%. Eleutherodactylus grunwaldi lacks compact lumbar glands. Eleutherodactylus grunwaldi has a forearm length of 8.3 mm and four digits on each hand, with relative finger lengths of 1 < 2 < 4 < 3. The discs on the third and fourth fingers are expanded and are 2.5 - 3 times the diameter of the narrowest diameter of the third and fourth fingers. The femur length is shorter than the tibia length. The foot is 13.8 mm long and there are 5 digits on each foot, with relative toe lengths being 1 < 2 < 5 < 3 < 4. The fourth toe is the longest and the third toe is close behind. The toe discs are triangular and on the third and fourth digit they are expanded significantly, consistently reaching about three times larger than the smallest part of the same digit. The texture of their skin is smooth (Reyes-Velasco et al. 2015).

DIAGNOSIS:

Eleutherodactylus grünwaldi is part of the subgenus Syrrophus in the genus Eleutherodactylus. Many morphological traits of E. grünwaldi are similar to other species within this genus, such as its broad finger discs, fairly large size, and coloring, but it can be differentiated based on other traits. Eleutherodactylus grunwaldi shares the trait of enlarged finger discs with E. longipes and E. saxatilis. However, E. grunwaldi is distinguished from E. saxatilis because E. saxatilis has a smaller ratio of pad diameter compared with digit diameter (2:1 compared with 3:1 for E. grunwaldi). Eleutherodactylus saxatilis also has compact lumbar glands and E. grunwaldi does not. Even though they share similar sizes of finger discs, E. grunwaldi can be distinguished from E. longipes because its tympanum is smaller, never reaching larger than 50% of the width of the eye, while E. longipes can have a tympanum that reaches 60 - 90% of the width of the eye. Eleutherodactylus dennisi is another species that can be distinguished from E. grunwaldi by tympanum size, as it has a tympanum that is 50 - 60% the diameter of its eye. In addition to enlarged finger pads, the size of the toe pads can distinguish E. grunwaldi from other species in its genus. In E. grunwaldi, they are over two times the size of the smallest diameter of the digit, while E. nitidus’ toe pads are only 1.5 times the size of the width of their digits. Eleutherodactylus grunwaldi can be distinguished from E. nivicolimae by difference in size with E. grunwaldi males measuring over 28 mm from snout to vent and E. nivicolimae males measuring under 23.5 mm. Coloration also sets E. grunwaldi apart. While E. grunwaldi consistently has yellow and green splotches on a dark background, E. nivicolimae lack spots and has a background color that can range in color from gray to yellow to red (Reyes-Velasco et al. 2015). For a key to distinguishing members of the Syrrhophus subgenus see Grünwald et al. 2018.

COLORATION:

In life, E. grunwaldi has a dark gray dorsum with a net-like pattern of yellow-green splotches along its back, neck, head, and limbs. The ventrum of this frog is white and it has pale gray hands and feet. The feet have no markings, while the hands have some very subtle markings. There is a gray line that runs from the nostril through the eye and disappears into other gray coloring behind the tympanum. Their irises are copper green. In preservative, E. grunwaldi maintains its dark gray background coloring, but the yellow-green reticulations become a very light brown-gray. It also maintains its white ventrum (Reyes-Velasco et al. 2015).

VARIATION:

While most individuals of E. grunwaldi have been described as largely similar, some variation in color has been noted. While they all have a dark background color with yellow-green splotches on top, there is variation in the splotches themselves, both in depth of the color as well as the pattern of the splotches, with some of them being much more of a net-like pattern than others (Reyes-Velasco et al. 2015).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Mexico

View distribution map in BerkeleyMapper.

Eleutherodactylus grunwaldi is found in Mexico, in the states of Jalisco, Colima, Tolimán, and Minatitlán, specifically in the Sierra de Manantlán Biosphere Reserve. This area contains tropical deciduous forests as well as pine-oak woodland. Eleutherodactylus grunwaldi is found in both of these habitats, as well as the area that connects them. One of the important parts of the ecosystem that E. grunwaldi lives in is limestone, where it can be found in exposed formations, caves, or depressions in the ground. Eleutherodactylus grunwaldi has been found as low as 800 meters above sea level in Jalisco and as high as 1,300 - 2,200 meters above sea level in Sierra de Manantlán Biosphere Reserve (Reyes-Velasco et al. 2015).

Life History, Abundance, Activity, and Special Behaviors
Little is known about the life history of E. grunwaldi. Males are seen calling during rainy season nights. Specimens have been found on perches such as trees, likely to increase the range of their calls. This behavior is common amongst the Syrrhophus subgenus, of which E. grunwaldi is a member, due to their small size. Calls are distributed at a dominant frequency of 2.13 kHz for approximately 70 ms. They occur at an average call rate of 6 times per minute. Currently, it is unknown if females call as well (Reyes-Velasco et al. 2015).

Specimens are more common during the summer months due to the rainy weather. During this time, breeding likely occurs, similar to other frog species within the area (Reyes-Velasco et al. 2015).

It is found in sympatry with Eleutherodactylus manantlanensis (Grünwald et al. 2018).

Trends and Threats
Currently, E. grunwaldi is considered “Endangered” but stable (IUCN 2020). This species is most threatened by legal and illegal iron mining within their habitat (Grünwald et al. 2018). Another severe threat is deforestation from logging and the production of agricultural land. These practices have significantly harmed the surrounding ecosystem, leading to a decline in several organisms including E. grunwaldi (Reyes-Velasco et al. 2015).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Mining

Comments

PHYLOGENETIC RELATIONSHIPS:

Eleutherodactylus grünwaldi is part of the subgenus Syrrophus in the genus Eleutherodactylus based on the morphological traits of broad finger discs, fairly large size, and coloring. Despite this, it does not appear to be especially closely related to the species with which it shares these characteristics (Reyes-Velasco et al. 2015).

At the time of the species description, preliminary phylogenetic analysis of 16S ribosomal RNA gene indicated that E. grünwaldi is most closely related to species in the E. modestus group (Reyes-Velasco et al. 2015). This was reiterated in Grünwald et al. (2018), which described six other species.

ETYMOLOGY:

This species is named after the first person to collect a specimen of it, Christoph I. Grünwald. This occurred on July 18th, 2005 near El Terrero, Municipality of Minatitlán, Colima (Reyes-Velasco et al. 2015).

References

Grünwald, C. I., Reyes-Velasco, J., Franz-Chávez, H., Morales-Flores, K. I., Ahumada-Carrillo, I. T., Jones, J. M., Boissinot, S. (2018). “Six new species of Eleutherodactylus (Anura: Eleutherodactylidae: subgenus Syrrhophus) from Mexico, with a discussion of their systematic relationships and the validity of related species.” Mesoamerican Herpetology, 5, 6-83. [link]

IUCN SSC Amphibian Specialist Group. (2020). "Eleutherodactylus grunwaldi". The IUCN Red List of Threatened Species 2020: e.T78496612A95517314. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T78496612A95517314.en. Accessed on 21 February 2022.

Reyes-Velasco J., Ahumada-Carrillo I., Burkhardt T. R., Devitt T. J. (2015). “Two new species of Eleutherodactylus (subgenus Syrrhophus) from western Mexico.” Zootaxa, 3914(3), 301-317. [link]

Species Account Citation: AmphibiaWeb 2022 Eleutherodactylus grunwaldi: Grünwald’s Piping Frog <https://amphibiaweb.org/species/8306> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

AmphibiaWeb's policy on data use.