Description
Bromeliohyla bromeliacia is a small bromeliad-inhabiting frog with a male snout to vent length is of about 24.1 - 29.5 mm in males and 32.0 - 36.0 mm in females. The flat, short head is as broad or broader than the body. The head length and width are approximately equal. In the dorsal view, the moderately long snout is acutely rounded and in the lateral view the snout is bluntly rounded. The nostrils are somewhat prominent and found closer to the snout, roughly 3/4th the distance from the eyes to snout tip. The distinct canthus rostralis is slightly angular and the loreal region is concave. The lips are barely flared and thick. The eye is as long as the snout. The tympanum is distinct and located behind the eye at a distance slightly greater than the diameter of the tympanum, which is a third the diameter of the eye. A thin supratympanic fold begins behind each eye and continues above the tympanum, slightly obscuring it at the upper edge, and ends above the insertion of the arm (Schmidt 1933, Duellman 1970).

The arms are short and thick, with a short axillary membrane and a clear row of tubercles on the ventrolateral edge of the forearm. There is also an obvious dermal fold on the wrist. The large palmar tubercle is flat and bifid. The fingers are short and thick and have large discs. The disc of the third finger is approximately the same diameter of the eye while the other discs are approximately the size of the tympanum. Webbing on the hands is indistinct and vestigial. The moderate subarticular tubercles are flattened with the distal subarticular tubercle of the fourth finger being bifid. The hands have large, subconical supernumerary tubercles that are especially dense on the proximal portion of the third finger. In breeding males, the moderate prepollex has horny nuptial excrescences and the base of the thumb has as velvety pad (Schmidt 1933, Duellman 1970).

The hind limbs are also short and thick. When the legs are held at right angles to the body, the shanks overlap by one-fifth their length and when the leg is adpressed along the body, the heel reaches the region between the eye and the tip of the snout. The heel is tubercular with a heavy transverse dermal fold. There is also a low, indistinct tarsal fold that extends along the whole tarsus. The flat, low, elliptical inner metatarsal tubercle can be seen from the dorsal view. The small outer metatarsal tubercle is subconical. The long and robust toes have discs that are smaller than the fingers. The tubercles on the feet are large with the subarticular tubercles being subconical and the supernumerary tubercles being round. The toes are approximately one to two-thirds webbed (Schmidt 1933, Duellman 1970) with a webbing formula of I 2 – 2+ II 1–2 1/2 III 1+ – 32 IV 32 – 1+ V (McCranie and Castañeda 2006).

The skin is smooth on the dorsal surfaces, ventral surface of the arms, and shanks of the hind limbs. The skin is nearly smooth on the posterior portion of the ventrum. The ventral surfaces of the hind limbs and belly are granular and the throat is slightly granular. There is a singular, median, subgular vocal sac that is moderately distensible. The anal opening is located at the midlevel of the thighs and directed posteroventrally. It has a short anal sheath and large tubercles below the anal opening (Schmidt 1933, Duellman 1970).

At hatching (developmental stage 21), tadpoles have body lengths of 2.5 – 2.7 mm and total lengths of 6.7 – 7.1 mm. Body lengths at stage 25 form two distinct size groups that together can range from 3.8 – 9.0 mm. At stage 35, the typical body length is 9.3 mm and a total length of 31.0 mm. Body length at stage 41 is 10.3 – 10.5 mm and total length is about 30.5 mm. Body length at metamorphosis (stage 46) is 11.1 – 11.5 mm. Tadpoles at stage 35 have greatly flattened bodies, almost twice as wide than deep, and are widest at the posterior portion of the body. In the dorsal view, the snout is bluntly rounded and in the lateral view the snout is acutely rounded to the point of almost being spatulated. The nostril is located closer to the tip of the snout than the eyes and directed anteriorly. The small eyes are spaced widely and directed laterally. The ventral mouth is small with a width less than half the body width. The upper lip is bare and there are no lateral folds. The lower lip has two rows of small papillae. The massive beaks have moderately long, pointed serrations. The upper beak is shaped in a broad arch with short lateral processes while the lower beak is present as a narrow arch. There are two upper rows of teeth that are long and nearly extend to the lip. The second row has a medial interruption. The number of lower teeth rows varies from four to five with fewer rows found in the smaller subgroup at stage 25. Smaller individuals may have weakly developed third and fourth rows of teeth. Larger individuals typically have five fully developed rows, but always have at least four. The lower teeth rows have progressively shorter rows, but all are complete. The sinistral spiracle opening is located at the midline approximately two-thirds from the tip of the snout. The dextral anal tube is moderately long. The tail has extensive caudal musculature and a rounded tip. The dorsal fin does not extend onto the body. The tail fins in general are shallow with the deepest portions being towards the posterior (Duellman 1970).

When first described, B. bromeliacia appeared the most similar to Exerodonta sumichrasti but could be distinguished by the former having prominent vomerine teeth, a more distinct tympanum, rounded snout, shorter digit webbing, and a tarsal fold (Schmidt 1933, Duellman 1970). Bromeliohyla bromeliacia can be distinguished from its close relative Bromeliohyla dendroscarta by B. bromeliacia having hind limbs that are proportionately shorter and thicker, a blunter snout, pigments on the ventral surfaces of the palms and feet, and a dark pigment on the throat (Duellman 1970, McCranie and Castañeda 2006). From Bromeliohyla melacaena, the focal species can be distinguished by its larger size, small nuptial excrescences on the thumb (vs. large spines), more toe webbing, lack of sexual dimorphism, and opaque ventrum. At some point, specimens of the Jamacian Osteopilus wilderi were also mixed up with B. bromeliacia but could be distinguished by O. wilderi having large thumb spikes (McCranie and Castañeda 2006).

Tadpoles of Bromeliohyla can be differentiated from those of closely related genera Duellmanohyla and Ptychohyla by their labial tooth row formula. For the former it is 2/4 or 2/5 while in Duellmanohyla it is 3/3 and the minimum known for Ptychohyla is 3/5 (Faivovich et al. 2005). For other similar species, B. bromeliacia tadpoles can be differentiated from those of E. sumichrasti by the former having a full complement of horny teeth (Schmidt 1933). From Isthmohyla zeteki, the focal species can be distinguished by its well developed tooth rows, depressed body, and long tail. The mouthparts of B. bromeliacia also distinguish it from similar Jamaican bromeliad tadpoles, Oreophyrne brunnea, Osteopilus crucialis, Osteopilus marianae, and Osteopilus wilderi (Duellman 1970).

In life, the dorsal coloration of the head and the body are pale brown to dull yellowish tan depending on the time of day (darker during the day, lighter at night). In the yellowish tan phase, fine flecks of either dark or white coloration are present on the dorsum. They otherwise possess no distinguishable markings (Schmidt 1933, Duellman 1970). The iris is generally dull bronze with flecks of black, and some irises have an indistinct white strip. The side of the body and posterior portion of the hind limbs are a pale pinkish tan. The ventral side of the thighs is a dull yellow and the venter is white. The throat is pigmented more darkly. Some specimens have a faint white anal strip. In preservative, the dorsum is dull tan to brown and may have dark minute flecks. The flanks, thighs, and dorsal surface of the first two toes are tan. The ventrum is creamy tan with a suffusion of brown on the throat. The ventral surfaces of the hands and feet are brown, especially on the supernumerary tubercles of the feet (Duellman 1970).

In life, the dorsal surface of tadpoles is dull tan to creamy brown while the ventrum is transparent, clearly showing the heart. In preservative, the dorsal surface and caudal musculature becomes a pale creamy tan with black flecks. The fins of the tail are transparent (Duellman 1970).

The species show sexual dimorphism in size, with females being larger than males (Faviovich et al. 2018). Males possess a disc shaped glandular structure in the abdomen that is not found in females (Schmidt 1933). Males also have small distinct nuptial growths on the thumbs (McCranie and Castañeda 2006).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Belize, Guatemala, Honduras

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (6 records).

The range of B. bromeliacia extends through Belize, Guatemala, Honduras and Mexico and is approximately 50,567 km². Their elevation range is 350 - 1,790 m asl. In Mexico, it is found in northwestern Chiapas State on the Atlantic versant. In Guatemala, it occurs in central and eastern regions. It can be found in northeastern Honduras and occurs in the Maya Mountains of Belize. They inhabit wet forests in premontane and montane areas (IUCN 2014).

Life History, Abundance, Activity, and Special Behaviors
Bromeliohyla bromeliacia is known for its association with bromeliads. They live in the bromeliads and use them for breeding. More specifically, bromeliads are used for ovipositing sites and are where larval stage progresses to completion (Schmidt 1933, Duellman 1970, Faviovich et al. 2018).

The species is thought to have a year-round breeding season as varying stages of eggs and tadpoles have been found. Males call softly from bromeliads or the leaves and branches of trees (Duellman 1970). Their call resembles the distinct, isolated strokes of a bell (Schmidt 1933). It consists of 5 – 6 soft notes that each last 0.14 seconds for a total duration of about 5 seconds repeated in 45 – 70 second intervals. Sometimes the last note in the call group is doubled or tripled. The calls have a pulse rate of 195 pulses per second, a dominant frequency of about 3100 Hz, and a fundamental frequency of 135 Hz. Males are difficult to locate based solely on their call because of the directional influence of the bromeliad and the softness of the call (Duellman 1970).

Eggs, with pigmented animal poles (Faivovich et al. 2005, 2018), are deposited in clusters of about a dozen under the water line at the base of and between leaves in bromeliads. The eggs are contained loosely in pairs in a watery gelatin. After hatching, the tadpoles can be found wriggling at the base of the leaves and have been observed moving over wet surfaces of leaves, out of the water, by forcefully wiggling their tails (Duellman 1970).

Trends and Threats
The primary threat faced by B. bromeliacia is deforestation for crops and livestock. They are also affected by the effects of agrochemical use and illegal logging on the periphery of the Sierra Caral protected area. Illegal logging also occurs at Parque Nacional Cusuco. Population declines at higher elevations have been attributed to chytrid fungus, which have occurred in populations in Cusuco. Droughts also pose a problem due to this species’ reliance on wet forest conditions, including high humidity (IUCN 2014).

Possible reasons for amphibian decline

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

Comments
The species authority is: Schmidt, K. P. (1933). “New reptiles and amphibians from Honduras. Field Museum of Natural History Publication.” Zoological Series 20: 15–22.

Based on morphology and life history, B. bromeliacia was thought to be closely related to B. dendroscarta (Duellman 1970). This was further supported by Faivovich et al. (2005) in their phylogenetic analysis of nuclear and mitochondrial genes of the family Hylidae that included both species. Based on this evidence, Faivovich et al. (2005) created the genus Bromeliohyla. In 2018, Faivovich et al. re-estimated the Hylidae phylogeny resulting in the addition of B. melacaena (formerly of the genus Isthmohyla) to the genus Bromeliohyla with 87% jackknife support.

The genus name Bromeliohyla is the combination of the words “Bromelia” and “Hyla”, to represent the characteristic behavior of breeding in bromeliads (Faviovich et al. 2005).

The species epithet, “bromeliacia” is also a reference to the species relationship with bromeliads. More specifically, “bromeliad” is the generic name of the group of bromeliads the frog uses, and “aceus” is Latin for “belonging to” (Schmidt 1933, Duellman 1970).

References

Duellman, W.E. (1970). The Hylid Frogs of Middle America. Monograph of the Museum of Natural History, University of Kansas.

Faivovich, J., Haddad, C. F. B., Garcia, P. C. A., Frost, D. R., Campbell, J. A., Wheeler, W. C. (2005). ''Systematic review of the frog family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision.'' Bulletin of the American Museum of Natural History, (294), 1-240. [link]

Faivovich, J., Pereyra, M.O., Luna, M.C., Hertz, A., Blotto, B.L., Vásquez-Almazán, C.R., McCranie, J.R., Sánchez, D.A., Baêta, D., Araujo-Vieira, K., Köhler, G., Kubicki, B., Campbell, J.A., Frost, D.R., Wheeler, W.C., Haddad, C.F.B. (2018). ''On the monophyly and relationships of several genera of Hylini (Anura: Hylidae: Hylinae), with comments on recent taxonomic changes in Hylids.'' South American Journal of Herpetology, 13(1), 1-32. [link]

IUCN SSC Amphibian Specialist Group (2014). ''Bromeliohyla bromeliacia''. The IUCN Red List of Threatened Species 2014: e.T55422A53953100. http://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T55422A53953100.en. Downloaded on 16 May 2019.

McCranie, J.R., Castañeda, F.E. (2006). ''A new species of hylid frog from northwestern Honduras.'' Herpetologica , 62(3), 318-323. [link]

Schmidt, K. P. (1933). ''New reptiles and amphibians from Honduras.'' Zoological Series of Field Museum of Natural History , 20, 5–22. [link]

Species Account Citation: AmphibiaWeb 2022 Bromeliohyla bromeliacia: Bromeliad Treefrog <https://amphibiaweb.org/species/745> University of California, Berkeley, CA, USA. Accessed Nov 12, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 12 Nov 2024.

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