La Loma Robber Frog

Pristimantis caryophyllaceus has a snout-vent length of 12.0 – 21.2 mm in males and 16.7 – 26.2 mm in females. The head is longer than it is wide, and its snout appears rounded when viewed from the back and the sides. The snout tip is minutely pointed, and protrudes past the nostrils. The nostril openings are oval and directed upwards. It has a somewhat rounded and sharp canthus rostralis. The upper eyelid is smooth, though it has a prominent tapered tubercle. The tympanum is faint in appearance and the tympanic ring is slightly discernible. The backside of the body is smooth. The sides are also smooth, though additionally punctuated with small tubercles. The underside is slightly coarse in texture, though smooth at the chin. There are oval subarticular tubercles under the fingers. The tubercle at the base of the thumb is lengthened, and the palmar tubercle is round and cleft in two. There are many minute, circular, protuberant tubercles that run down the underside of the forearm. The relative finger lengths are IV = III > I > II. The fingertips are widened and circular. There are many minute, circular tubercles that run down the underside of the legs. The toe tips are widened and circular. The subarticular tubercles on the toes are ovoid and flat. The toes have a faint lateral fringe. There are no tarsal folds or webbing on the feet. The inner metatarsal tubercle is small, extended, and faint. The outer metatarsal tubercle is small, circular, and faint. The heel has a large tapered tubercle. The relative toe lengths are IV > V > III > II > I (Ryan et al. 2010).It is part of the P. ridens species group, which can be distinguished by the following combination of characters: relatively small size (snout-vent length is 16.0 – 45.2 mm); discernible tympanic membrane and ring; smooth, grainy, or tuberculate back; coarse underside; lack of webbing on feet; Toe V longer than Toe III; presence of inner tarsal fold. It is most similar in appearance to P. educatoris, but can be distinguished by the following combination of characters: smaller average size; non-protuberant subarticular tubercles; widened and circular fingertips and toe tips; small, extended, faint inner metatarsal tubercle; small, circular, faint outer metatarsal tubercle; tip of Toe V extends past distal subarticular tubercle of Toe IV; Toe I extends past distal subarticular tubercle of Toe II; absence of warty white spots on back, arms, and sides (Ryan et al. 2010).In life, the backside is light to medium brown, and has 4 – 5 dark brown V-shaped patterns. The underside is white. Some individuals have a wide brown band running down the midline of the back. The iris color varies, and may be bicolored. The upper half of the iris may vary from bright red to yellow-orange, and the bottom half of the iris may vary from dark purple to dark grey. The eyes of other specimens may be completely red, yellow, or grey. There may be a white ring around the eye. In preservative, the back is medium to dark brown, and has 4 – 5 dark brown V-shaped patterns. The limbs are light brown and have darker brown bars on the sides as well as spotting. The underside is an uneven white. The back and underside have fine black spotting (Ryan et al. 2010).Males are significantly smaller than females. Additionally, males have a very faint tympanum, whereas it is indistinct but still noticeable in females. Eastern Panamanian populations tend to be larger in size and have larger fingertips and toe tips than western Panamanian populations. There is much variation in color as described in the preceding paragraph (Ryan et al. 2010).The species authority is: Barbour, T. (1928). "New Central American frogs." Proceedings of the New England Zoological Club, 10, 25-31.It was initially described as Syrrhophus caryophyllaceus in 1928. It was subsequently ascribed to the genus Eleutherodactylus in 1937, before being placed in its current genus Pristimantis in 2007 (Barbour 1928, Dunn 1937, Heinicke et al. 2007).It is part of the P. ridens species group, comprising P. altae, bicolor, caryophyllaceus, colomai, cremnobates, cruentus, jorgevelosai, laticlavius, latidiscus, moro, museosus, pardalis, pirrensis, ridens, rosadoi, and sanguineus (Hedges et al. 2008).Pristimantis caryophyllaceus shows high genetic diversity as well as noticeable morphological variation between three distinct populations throughout its Panamanian range. In 2010, a study showed that several specimens previously considered P. caryophyllaceus were actually P. educatoris, a morphologically similar yet genetically distinct species. A later study suggested that due to the high genetic diversity between P. caryophyllaceus populations, there is insufficient evidence to support the validity of P. educatoris as its own species (Ryan et al. 2010, Batista et al. 2014).The high genetic diversity in Panamanian populations may be due to the geologically active history and relatively recent formation of the Isthmus of Panama, resulting in multiple vicariance events (Batista et al. 2014).

This species occurs at lower elevation areas in the slopes of northeastern Costa Rica to central Panama west of Panama City. It resides in leaf litter and low-hanging vegetation in primary rainforests. There is a disjunct population that runs north of Panama City and extends southeast to the border with Colombia. A single isolated population occurs in Colombia, in Parque Nacional Natural Las Orquideas in the Chocó Department. It has an altitudinal range of up to 1900 m asl in Panama, and at least 1500 m asl in Colombia (Batista et al. 2014, Pounds et al. 2008).

Females lay their eggs on leaves and brood them. The young develop directly and hatch as froglets (Pounds et al. 2008).

It is protected in several areas in Costa Rica and Panama. A 2004 study in In El Copé, Panama, where this species is found, showed that several amphibian populations were severely devastated by the chytrid fungus Batrachochytrium dendrobatidis. However, as insufficient studies have been conducted on its population trends, it is uncertain how impacted P. caryophyllaceus was by the fungus (Lips et al. 2005, Pounds et al. 2008, Ryan et al. 2010).

Pristimantis caryophyllaceus is a species of frog in the family Strabomantidae. It is found in Costa Rica and Panama; records from Colombia prior to 2010 refer to Pristimantis educatoris. However, taxonomy of Pristimantis caryophyllaceus and P. educatoris remain unsettled, and many sources continue to report Pristimantis caryophyllaceus from Colombia.

Pristimantis caryophyllaceus is sometimes known as the La Loma robber frog, after La Loma, its type locality on the trail between Chiriquicito and Boquete, in the Bocas del Toro Province of Panama.