Dendrobates daleswansoni, Rueda-Almonacid & Rada & Sánchez- Pacheco & Velásquez-Álvarez & Quevedo, 2006

Rueda-Almonacid, José Vicente, Rada, Marco, Sánchez- Pacheco, Santiago J., Velásquez-Álvarez, Álvaro Andrés & Quevedo, Alonso, 2006, Two new and exceptional poison dart frogs of the genus Dendrobates (Anura: Dendrobatidae) from the Northeastern Flank of the cordillera Central of Colombia, Zootaxa 1259, pp. 39-54 : 41-48

Dendrobates daleswansoni new species

Holotype: An adult female deposited in the amphibian collection of the Instituto de Ciencias Naturales­Museo de Historia Natural of the Universidad Nacional de Colombia, Bogotá, ICN 42308 (field number VR 4774 ) is one of a series collected on 12 November 1992 by José Vicente Rueda, César Eduardo Barbosa, José Nicolas Rueda, Fabio Quevedo Aldana (r.i.p.), Humberto Piñeros and Alirio Fajardo Patiño.

Type locality: Colombia, Departamento de Caldas, Municipio de Samaná, Corregimiento de Florencia, Parque Nacional Natural Selva de Florencia , sitio ¨ El Estadero ¨, 1950 m, on the eastern flank of the cordillera Central, ca 5° 30' North . 75° 5' West .

Paratopotypes: Adult males: ICN 53278, ICN 53277, taken by José Vicente Rueda et al, 14 July 1992 and 10 June 1994; adult females MUJ 5154 , IND­AN 5445 ; adult male: MUJ 5155 ; ICN 42308­37 , 10 August 1993; juvenile: MUJ 5153 . Locality data are the same as the holotype .

Etymology: This species is named in honor of the late Dale Swanson (1927–2003) of Spokane, Washington, in the United States of America. Dale had been a life­long conservationist who traveled to more than 100 countries and was a committed supporter of Conservation International and other NGOs. His generous contributions to biodiversity conservation, particularly in top priority biodiversity hotspots like the Tropical Andes, made studies like the one presented here possible.

Definition and Diagnosis: A small dendrobatid frog having an adult snout vent length of about 18.8 mm (maximum 19.7 mm) and a red cephalic “hood” and anterior with the color extending onto the front arms and ending just past the occipitomaculata region where it merges with the ground color/brown, immediately distinguishable from the other frogs of the family because this frog has the first toe reduced and fused with the second toe, which allows just four toes to be seen externally. Phalanges toe formula: 1­2­3­4­3.

This frog can be assigned to the minutus group. It can be recognized for possessing only four externally visible toes on the hind limbs, for its brilliant red cephalic "hood," and the lack of vomerine and maxillary odontophores. It has a concealed tympanum; the first finger shorter than the second; fingers and toes lack webbing; outer tarsal tubercle well developed and the digits end in paired dermal pads ( Figures 1 and 4).

Description of the type specimens: Based on 3 adult males and 3 adult females. The head slightly longer than wider and much narrower than the body. Snout rounded in dorsal view and truncated in lateral view. Prominent nares, situated much closer to the end of the snout than to the eye, only visible in front and ventral view (not dorsal), of an ovoid form and directed posterolaterally. Canthus rostralis rounded, loreal region flat and vertical. Interorbital distance flat and wider than the width of the superior eyelid. Eye large and prominent with a maximum diameter of 13.1% (average) of the snout vent length, rounded pupil and horizontally elliptical. Tympanum and tympanic ring hidden in the posterodorsal region, ovoid and directed anteroventrally, the maximum diameter taken diagonally is 22.5–34.1% of the diameter of the eye ( Tables 1 and 2). Supratympanic fold absent.

Postrictal tubercle absent; rounded choanae, not visible in ventral view, as they are completely covered by the maxillary arch. Vomerine, maxillary and premaxillary teeth absent. Tongue elongated, almost two times longer than wider, the posterior margin not indented and posterior third not adhered to floor of mouth. Median lingual process absent (sensu Grant et al. 1997).

Hand relatively large, with a length equal to 24.2–26.8% of the snout vent length. The relative length of the fingers in increasing order of size is I<II<IV<III; the tip of the IV digit reaches the middle of the second to last phalange of the III digit and the distal extreme of the first digit reaches the base of the disc of the second digit. Discs moderately expanded on digits of the hand, except the pollex, on which the width of the disc does not exceed that of the digit. Paired dorsal pads on dorsal surfaces of the discs present. Outer metacarpal tubercle somewhat flat and rounded, internal metacarpal tubercle elliptical and located at the base of the first finger, basal subarticular tubercle rounded and flat over the fingers I and II, and two subarticular tubercles rounded and flattened over the III and IV digits ( Figure 4).

Hind limbs relatively short, when these are extended forward along the body, the heel reaches the posterior edge of the eye; when the thigh is flexed perpendicular to the sagittal line and the legs are extended backwards, the heels barely overlap. The relative length of the toes in order of decreasing size is IV>III>V>II.

Discs of toes smaller than disks on fingers, however, wider than digits below the respective discs. Toe II with the basal subarticular tubercle not protuberant. Toes III and V with two subarticular tubercles and toe IV with three subarticular tubercles. Supernumerary plantar tubercles absent. Absent or very vestigial toe webbing. External metatarsal tubercle protuberant, elongated and barely greater that the size of the inner metatarsal tubercle ( Figure 4). A small and slight tarsal fold over the inner edge of the third distal of the tarsus.

Skin on the back generally smooth with few small flat warts barely discernable in the sacro­coccigea region and the hind limbs; flank and belly skin granular.

Color in life: Black iris. Cephalic hood Prats Ruby ( Smithe 1975), which extends to the axille and completely covers the supraescapular region and the back of the arms; remaining body surfaces are Antique Brown or Robin Rufous ( Smithe 1975). Ventral surfaces sepia colored with cinnamon infusions, especially concentrated over the chin and the throat. On the flanks, the sepia color of the abdomen gradually attenuates towards the dorsal side. Occasionally, individuals display one or several yellow­orange dots over the posterior surface of the trunk and thighs.

Color in preservative (ethanol 70%): Back and belly uniformly sepia or dark brown, somewhat lighter towards the anterior region of the body. The yellow­orange spots turn grey in preservative. Males have cream­colored testes with fine brown reticulation. Eggs brown.

Dimension of the Holotype (mm): The holotype corresponds to an adult female with a snout vent length of 19.01; tibia length of 7.95; maximum body width of 7.83; head width of 6.15; interorbital distance of 2.55; cephalic distance of 4.89; distance between the snout and nares of 0.79; distance between the nares and the eye of 1.43; distance between the nares of 3.04; eye diameter of 2.16; tympanum diameter of 0.9; distance from the posterior corner of the jaw to the inferior edge of the tympanic ring of 0.59; hand length of 5.24; disc width in the third finger of 0.76; width of the third finger of 0.51; disc width in the third toe of 0.50; disc width in the fourth toe of 0.57; width of the fourth toe of 0.55.

The dimensions and percentage relationships of the type specimens are shown in Tables Nos. 1 and 2.

*The abbreviations used are: SVL (snout­vent length), TL (tibia length), MBW (maximum body width), HW (head width), IOD (interorbital distance), CL (cephalic length), ST­CN (Snout tip – center of nare), CN­E (center of nare – edge eye), IND (internare distance), ED (eye diameter), DT (diameter of tympanum), MC­T (mouth corner­lower edge of tympanic ring), HL (hand length), DcW­IIIf (disc width on third finger), W­IIIf (width third finger), DcW­IIIt (disc width on third toe), DcW­IVt (disc width on fourth toe), W­IVt (width of fourth toe).

Distribution: Species known in the cloud forests in the northern cordillera Central of Colombia, between 1800–2000 m, in the departamento de Caldas (Municipio Samaná).

Sexual Dimorphism: Among the most significant morphological differences that allow differentiation between adult males and females are the following characteristics and are exclusive to the former: the presence of vocal slits and a single, subgular vocal sac, smaller body size, greater hand length and the third finger disc has a transversal extension equal to 1.6 times the width of the digit at the second to last phalange. Generally the cephalic width in males does not exceed the abdominal width. Males tend to have thinner bodies and more granulated skin on ventral surfaces and thighs than females.

Natural History: A relatively common diurnal dendrobatid found in forested habitats. This species is especially active on sunny mornings when it can be seen jumping among the fallen leaves during all year. If they are disturbed, they seek refuge under leaves or in fissures or holes in rocks. Several individuals were captured in the bark of a fallen rotting tree. This species appears to inhabit the wettest areas of the understory in both primary and secondary forests. The vocalizations and sightings of this species suggest a concentrated distribution restricted to those forested areas with moderate leaf litter, high humidity and the presence of abundant refuges or holes in the ground, such as those present in flatter areas.

This species and Dendrobates opisthomelas are sympatric at altitudes around 1800 m; above this altitude D. daleswansoni replaces the D. opisthomelas species. The male vocalization is similar to a cricket chirp. Males transport one or two tadpoles on their backs to arboreal bromeliads, where they are left to finish their metamorphosis. Up to six larvae in different states of maturity were found inside the same bromeliad, along with juvenile Gastrotheca nicefori , Bolitoglossa ramosi and Eleutherodactylus uranobates .

The Bosques de Florencia are located in the transitional zone between the warm and cold thermal floors on the eastern flank of the cordillera Central in the departamento de Caldas, at altitudes ranging between 800m and 2,200m, covering approximately 13,000 hectares.

The climatic characteristics of the region provide an average temperature of 15–20 ºC and more than 4000 mm of precipitation annually. The rainfall pattern follows the bimodal model characteristic of the Andean region, in which there are two rainy seasons and two dry seasons annually. The hardest rains occur between August and December with monthly rainfall values that oscillate between 513 and 542 mm and the driest months occur during the first trimester of the year and receive about 296 mm.