Description
Andinobates cassidyhornae is a frog with a snout-vent-length of about 19.03 ± 0.31 mm. The head is marginally wider than it is longer, and is thinner than the body. From a dorsal perspective the snout is oval, while it seems truncated from a side view. The loreal region is leveled and upright. The elliptical nostrils are closer to the snout than the eyes and located posterolaterally. The eyes are large and have an approximate diameter of 1/10th of the total snout-vent-length with a horizontal oval shaped pupil. Located on the side and to the back of the head are the tympana and tympanic rings, both are oval in shape and wider dorsoventrally; despite being two different structures they are both about half the size of the eyes. Andinobates cassidyhornae has no supratympanic folds. The hands are large with a total size of about 1/4th of the total snout-vent-length; all digits have discs and increase in length in the following way: 4 < 2 < 1 < 3. In this way, the tip of the first digit reaches the base of the disc of the second digit, while the top of the fourth digit reaches the middle of the third digit. Hands also have paired dorsal pads on dorsal surfaces of the discs. There are flat and circular subarticular tubercles on the outside, and elliptical subarticular tubercles on the inside of the first digits; flat and circular basal subarticular tubercles are also on first and second digits. On hand digits three and four there are two circular and leveled subarticular tubercles, but the latter subarticular tubercles are not prominent. The relative length of the toes from smallest to largest are 1 < 2 < 5 < 3 < 4, all having discs, although not as big as finger discs. The basal subarticular tubercle of the second toe does not protrude; toe three and five have two subarticular tubercles, and toe four with three subarticular tubercles. There are no supernumerary plantar tubercles present and the inner metatarsal tubercles are larger than the external metatarsal tubercle. Final note, there are traces of toe webbing. In males, one vocal slit is present (Amezquita et al. 2013).

Andinobates cassidyhornae can be clearly distinguished by its distinctive color pattern and advertisement calls from other species in the Andinobates bombetes group. Physically, for example, A. cassidyhornae has a red dorsum with irregular black spots and black venter with red irregular spots (also see coloration section below), it can be easily differentiated from: (1) A. ophisthomelas that also has a black venter but possess numerous white spots, (2) A. virolinesis whose venter can be whitish or bluish with black spotting, (3) A. bombetes that has a red dorsum but yellow or orange broad and longitudinal stripes rather than black irregular spots, (4) A. tolimensis whose dorsum is brown with a yellow head, (5) A. dorisswansonae has a black dorsum with red spots but possess a black venter with a few white or yellow spots, (6) and A. daleswansoni whose the body is entirely dull gold or brown color with a red head. Clearly A. cassidyhornae possess a distinct coloration (Amezquita et al. 2013).

In life, A. cassidyhornae has a very dark brown iris that is sometimes indistinguishable from the black pupil. The nares, tympana, and the margins of the upper and lower jaws are also either very dark brown or black. The entire backside is bright red with a few random scattered black spots and markings; however, on other specimens black markings may also represent previous predator attacks and should not be considered as part of the coloration. From a side perspective, the flanks are red while ventrolaterally it is black with no color merging. The underside is black with randomly placed irregular shaped red spots. Forearms are bright red near the top, tinged brown near the middle, dark brown at the bottom, wrists and hands are brown, and the tips of the toes and fingers are beige. The species is bright red on the thighs with occasional brown spots and the shanks are brown with occasional red marks. In preservative, all the dark brown and black areas turn dull black to dark olive. Over time the discs and tubercles on hands and feet, pupil and cornea become grey or nearly white. Despite keeping its pattern clearly distinguishable, the bright red dorsal color and the underside red spots turn metallic olive (Amezquita et al. 2013).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Colombia

View distribution map in BerkeleyMapper.

Andinobates cassidyhornae can be found in the highland cloud forests of the Mesenia-Paramillo Natural Reserve. This heavily disturbed cloud forest of approximately 1.52 hectare is located on a steep montane slope with an estimated gradient of 65%. This mountainous forest section has trees up to 20 meters high with broken canopy surrounded by cattle grazing grasslands and agricultural crops. The forest is mainly made up of Lauraceae, Oak, and Cedar trees; while shrubs and small trees such as Ericaceae, Gesneriaceae, Melastomataceae, Piperaceae, and Rubiaceae make up most of the forest’s understory. At the bottom of the forest, the floor is covered with a lot of leaf litter and decomposing wood, simultaneously, pieces of inflorescences of Wettinia kalbreyerii palms usually serve as good terrestrial water reservoirs for long periods of time. Almost every morning and evening a cloud cover of fog, mist, and precipitation provides a cool and humid ambiance. In this environment the average annual rainfall is 2500 mm and lack other water sources such as streams or springs. Beginning in March through May and from October through December are the only two evident wet seasons, annually though, the average annual regional temperature is about 15.0° C. Andinobates cassidyhornae can also be found in Andes, Ciudad Bolivar, and Carmen de Atrato which are also part of the northwestern Colombian Andes and are practically similar in topography (Amezquita et al. 2013).

Life History, Abundance, Activity, and Special Behaviors
Little is known about the natural history of this newly found species. However, males were recorded articulating longer than 1-second advertisement calls that make a “buzz” type of sound, specifically one “buzz” per trunk muscle contraction. Pulses measured at 234.3 ± 20.3 (mean ± SD) seconds and last about 1.94 ± 0.26 seconds. These calls consist of a long series of pulses with amplitude and are separated by silent intervals of 10.1 ± 2.1 seconds lacking frequency modulation. Peak call frequency is approximately 4.32 ± 0.14 kHz and the frequency bandwidth at 0.81 ± 0.40 kHz. Additionally, the rise time is estimated to be 50.0 ± 13.2% of the call duration. Males tend to call regularly throughout the day from tree roots or leaf litter but are most active between midday hours and after rain. For reproductive behavior, males are known to carry 1 - 3 tadpoles on their back, but evidence of biparental care is still unknown (Amezquita et al. 2013).

Trends and Threats
Unfortunately for Andinobates cassidyhornae, its preferred range, from 1800 - 2059 m, has been severely degraded due to intensive agriculture. As a result of this severe forest degradation, Andinobates cassidyhornae is limited to a minor fraction of the available habitat. What available forest there is has been contaminated by pesticides, herbicides, and soil degradation which is also caused by agriculture and cattle grazing. The small distribution caused by disturbance of the forests it lives in is just one of the threats; massive smuggling also known as the illegal pet market poses another threat to the species. Currently there is an ongoing conservation project that involves the local community and The Hummingbird Conservancy (THC) foundation, which aim to increase the percentage of protected conservation areas (Amezquita et al. 2013).

Relation to Humans
This species is threatened by illegal pet trade (Amezquita et al. 2013).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Subtle changes to necessary specialized habitat
Habitat fragmentation
Local pesticides, fertilizers, and pollutants
Loss of genetic diversity from small population phenomena
Intentional mortality (over-harvesting, pet trade or collecting)

Comments
Pairwise genetic distances between A. cassidyhornae and other species in the A. bombetes species group ranged between 3.2 – 6.8% at the Cytb gene. The reconstructed phylogenetic tree and topology testing further offers strong evidence to support Andinobates cassidyhornae as a new species (Amezquita et al. 2013).

Named in honor of Cassidy Horn, this specific epithet cassidyhornae is a patronym for her interest and passion in poison frogs and also for her generous contributions to the conservation of cloud forests in Colombia (Amezquita et al. 2013).

References

Amezquita A, Marquez R, Medina R, Mejia-Vargas D, Kahn TR, Suarez G, Mazariegos L (2013). '' A new species of Andean poison frog, Andinobates (Anura: Dendrobatidae( from the northwestern Andes of Colombia.'' Zootaxa, 1620, 163-178.

Species Account Citation: AmphibiaWeb 2021 Andinobates cassidyhornae: Cassidy's Poison Dart Frog <https://amphibiaweb.org/species/7974> University of California, Berkeley, CA, USA. Accessed Nov 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Nov 2024.

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