Diasporus igneus, Batista, Abel, Ponce, Marcos & Hertz, Andreas, 2012

Batista, Abel, Ponce, Marcos & Hertz, Andreas, 2012, A new species of rainfrog of the genus Diasporus (Anura: Eleutherodactylidae) from Serranía de Tabasará, Panama, Zootaxa 3410, pp. 51-60 : 54-58

Diasporus igneus sp. nov.

Holotype. MVUP 2301 (original field number MHCH 1327), an adult male ( Fig. 3–5 ) collected on the southeastern slope of Cerro Santiago, Serranía de Tabasará about ca. 4.6 Km from Llano Tugrí (Buabití), capital of the Comarca Ngöbe Buglé, Distrito de Müna, Corregimiento de Peña Blanca, Panama, on March 25, 2009 at 19:35 (8.5079°N, 81.7168°W, 1710 m a.s.l.).

Paratypes. Three adult males from La Nevera, southwestern slope of Cerro Santiago, Serranía de Tabasará, Comarca Ngöbe-Buglé, Distrito de Nole Duima, Corregimiento de Jadeberi, Panama. MHCH 1388 and MHCH 2072 collected by A. Batista April 11, 2009, at 20:42 (8.4996°N, 81.7716°W, 1700 m a.s.l.) and April 12, 2009, at 02:05 (8.4998°N, 81.7719°W, 1700 m a.s.l.), respectively, and SMF 89821 collected by A. Hertz November 11, 2009 (8.4955ºN, 81.7672ºW, 1820 m a.s.l.).

Diagnosis. Diasporus igneus is characterized by the following combination of characters (see Table 1): (1) dorsal skin texture smooth with rounded scattered tubercles, edge of tibia and forearm with a series of low conical tubercles; (2) tympanic membrane not differentiated, tympanic annulus partially visible, 33.7 ± 4.6% (27.8–38.5) of eye length; (3) snout rounded in dorsal view and in profile; (4) an enlarged and conical supraocular tubercle, cranial crests absent; (5) dentigerous processes of vomers oblique, behind the choanae and posteriorly separated about half of their total length from each other; (6) vocal sac well developed, vocal slits present, no nuptial pads; (7) Finger II longer than Finger I, ungual flap mostly expanded, palmate to truncate, more evident on fingers II–IV, the III finger disk is 2.0 ± 0.2 (1.8–2.2) times wider than distal end of adjacent phalanx ( Fig. 5 ); (8) no fringes or webbing on fingers; (9) a row of rounded ulnar tubercles, most evident in life ( Fig. 3 and 5 ), palmar tubercle rounded, flattened and slightly larger than thenar tubercle; thenar tubercle low and elongate; subarticular tubercles rounded and globular; no supernumerary tubercles, palmar and plantar accessory tubercles small and rounded; (10) heel with two or three small and rounded tubercles; a row of rounded outer tarsal tubercles; (11) no fringes or webbing on toes, ungual flap mostly expanded, more evident on toes II–V, IV disc of toe is 1.8–2.3 (2.0 ± 0.2) times wider than distal end of adjacent phalanx; (12) plantar tubercle rounded, one to three non-protuberant subarticular tubercles present (one on toes I and II, two on toes III and V, three on toe IV); inner metatarsal tubercle elongated; outer metatarsal tubercles pointed and smaller than inner; tarsal ridge absent; (13) dorsal ground color in life brown with yellow to orange reticulations, groin and axilla red, vocal sac yellow; (14) SVL 26.1 ± 0.5 mm (25.5–26.6); (15) advertisement call composed of a single, amplitude-modulated short note (50.0–100.0 ms) with harmonic structure, and with most energy emitted with the first harmonic (2.2–2.5 kHz).

Similar species. Diasporus igneus can be distinguished from other species of the group as follows (see Table 1 for more details): from D. quidditus ( Lynch 2001) , D. tinker ( Lynch 2001) and D. vocator ( Taylor 1955) by its larger size and palmate to truncate ungual flap instead of lanceolate to papillate ungual flap. It differs from D. diastema ( Cope 1875) , D. tigrillo ( Savage 1997) , D. hylaeformis ( Cope 1875) , and D. ventrimaculatus (Chavez et al. 2009) by its larger body size, by having one to several enlarged supraocular tubercles, by having the outer edge of the tibia and forearm covered with a series of tubercles, and by having the groin and axilla colored in red. It is distinguished from D. anthrax ( Lynch 2001) , D. citrinobapheus ( Hertz et al. 2012) and D. gularis ( Boulenger 1898) by its larger size, dorsal skin with scattered tubercles, and its color pattern.

Description of the holotype. An adult male, with slender body; smooth dorsal skin with low widely spaced pustules, venter coarsely areolate, discoidal fold not evident; one enlarged supraocular tubercle, edge of tibia and forearm with a series of tubercles; eye slightly longer than snout; ratio SL/ED 77%; tympanum of moderate size, ratio TD/ED 38%; tympanum indistinguishable, annulus tympanicus partially visible through skin anteriorly and ventrally, positioned closely behind orbit and lower jaw; head slightly wider than long, greatest head width between angles of jaw 38% of SVL; snout rounded from above and in profile; nares situated near tip of snout and slightly dorsolaterally directed, barely visible in front view, also visible dorsally but not ventrally; canthus rostralis rounded; loreal region feebly concave; dentigerous processes of vomer 1.5 mm of length, and clearly visible, posterior to choana in an oblique outline, each with seven teeth; vocal slits present; tongue length 5.4 mm and 0.4 of width, first half attached to floor of mouth; hands moderate in size, 29% of SVL; relative lengths of adpressed fingers I<II<IV<III; finger IV slightly longer than II, finger II reaching the disk on finger IV when adpressed; finger III disk 1.8 times wider than distal end of adjacent phalanx; palmar tubercle rounded, flattened and slightly larger than thenar tubercle; thenar tubercle low and elongate; subarticular tubercles rounded and globular; no supernumerary tubercles; palmar and plantar accessory tubercles small and rounded; no nuptial pads; no fringes on fingers; hind limbs of moderate lengths, TL 44% of SVL; relative lengths of adpressed toes I<II<III<V<IV; when adpressed, tip of toe I reaches to tubercle of toe II; disc of toe IV moderately expanded, 1.8 times wider than distal end of adjacent phalanx; no fringes on toes; one to three nonprotuberant subarticular tubercles present (one each on toes I and II, two on toes III and V, three on toes IV); inner metatarsal tubercle elongated; outer metatarsal tubercles pointed and smaller than inner; tarsal ridge absent; hands and feet without webbing; finger and toe disks moderately expanded; ungual flap expanded, palmate; pads broadened and globular in profile ( Fig. 3–5 ).

Coloration of holotype in life. Holotype (MVUP 2301) ( Fig. 3 ) recorded as follows: iris Yellow Ocher (123) with a longitudinal Army Brown (219B) bar in the middle; dorsal ground color Verona Brown (223B), suffused with Clay Color (123D) and Burnt Orange (116); interorbital region with a Burnt Orange (116) line; groin and axilla immaculate Scarlet (14); posterior thigh surface Scarlet (14) suffused with Raw Umber (23), and with Buff (24) bars; venter immaculate Olive Yellow (52) suffused with Scarlet (14); vocal sac immaculate Orange Yellow (18).

Coloration in preservative (including paratypes, Fig. 4 –5). Dorsal ground color Buff (124), with reticulations Dark Brownish Olive (129), groin Warm Buff (118), vocal sac Trogon Yellow (153), ventral surface Chamois (123D) pointed with Sepia (119).

Measurements of holotype (mm). SVL 25.8; HL 8.2; HW 9.7; IOD 3.2; ED 3.3; TD 1.3; FL 11.6; TL 11.3; HAN 7.5; 3FW 0.7; 3FD 1.3; 3TW 0.6; 3TD 1.3; 4TW 0.8; 4TD 1.4; BW 13.8 (see table 2).

Vocalization. The vocalizations produced by the holotype (environmental temperature = 16.9 ºC; humidity 78%; 19:30) and two other males (MHCH 1388, environmental temperature = 16.1 ºC; humidity 86%; 20:30 and MHCH 2072, environmental temperature = 15.9 ºC; humidity 93%; 02:10) were analyzed. The calls consist of single, short, monophasic notes that are reminiscent of a “whistle” ( Fig. 6 ). Note duration is 0.07 ± 0.01 s (0.05–0.10) with an interval between calls of 13.5 ± 3.5 s (9.0–17.5) and a call rate of approximately four calls per minute. The peak frequency band ranges from 2.0 to 2.7 kHz. The fundamental frequency is also the dominant frequency, at 2.4 ± 0.08 kHz (2.2–2.5), followed by five main harmonic components at 4.6 ± 0.2 kHz (4.5–5.0), 6.8 ± 0.4 kHz (6.2–7.5), 9.3 ± 0.4 kHz (8.7–10.1), 11.8 ± 0.5 kHz (10.1–12.1), 13.6 ± 0.6 kHz (12.1–14.6)( Fig. 6 ), with most energy emitted in the first harmonic, followed by the second.

Natural history. This species is found in the lower - montane rain forest (1699–1815 m a.s.l.) in the western portion of the Serranía de Tabasará. The vegetation predominantly consists of big trees (roughly 30 m in height) covered with moss, bromeliads ( Werauhia spp . and Guzmania spp .), giant ferns ( Cyathea spp .) and orchids. The holotype was found calling inside a hole filled with dry leaves in a branch about two meters above the ground. The specimen MHCH 1388 was found calling from inside a bromeliad around five and a half meters above ground. The specimen MHCH 2072 was found calling from a moss-covered bark on a branch approximately five meters above the ground. The specimen SMF 89821 was not calling and sat exposed on a leaf about 0.7 m above the ground. Although the holotype and SMF 89821 were found at low heights, most calling individuals were sitting more than four meters above the ground. Calling individuals are well covered and hard to locate (after searching for approximately three hours at La Nevera, A. Batista could not detect a single individual, although he heard several of them calling). One paratype (MHCH 1388) was stimulated to regurgitate the contents of its stomach (technique provided by A. Amézquita), that contained a woodlouse (Isopoda: Oniscidea) of 2.9 mm length and 8.4 mm width.

Etymology. The species epithet igneus is the Latin word for fire, and is here used as a noun in apposition. It refers to the reticulated dorsum in contrast to the red coloration in the axilla and groin that is evocative of fire.

Remarks. All in all, the calls of most species of Diasporus appear to be very similar to one another to the human ear, and thus it is difficult to distinguish among them. Subjective description of the call types of the species D. anthrax , D. gularis , D. quidditus , D. tigrillo , and D. tinker have been mentioned (Chavez et al. 2009; Ibáñez et al. 1999; Lynch 2001; Savage 2002), but there are no data available for the acoustic properties of these species. Diasporus vocator from the western Pacific side of Panama (Río Chiriquí Viejo, 200 m a.s.l) calls at a highest frequency between 4.6 to 4.9 kHz (A. Batista, unpublished data), very different from that of D. igneus , which ranges from 2.0 to 2.7 kHz. The call of D. diastema from central Panama ranges between 2.8 to 4.0 kHz ( Fouquette 1960, Wilczynski & Brenowitz 1988), and appears to be most similar to that of D. hylaeformis , which also calls at highest frequency between 2.4 to 3.1 kHz (Chavez et al. 2009), rather than to that of D. igneus . The call of D. igneus is also different to that of D. citrinobapheus which call in bouts (8 to 22 calls per bout) at 2.9 kHz ( Hertz et al. 2012). The call most similar to that of D. igneus is that of D. ventrimaculatus , which range between 2.5 to 2.6 kHz, but they differ from one another in call rate, 11 calls/min in D. ventrimaculatus (Chavez et al. 2009) and 4 calls/min in D. igneus . Moreover, most species of the genus Diasporus diastema call at low elevations, between the ground and the understory ( Ibáñez et al. 1999, Lynch 2001, Savage 2002), but D. igneus call at higher elevations, from the understory to the mid-canopy.

Diasporus igneus has thus far only been encountered on the western and eastern slopes of Cerro Santiago. We suspect it to be also present on the southern and northern slopes. The estimated distribution area, the slopes of Cerro Santiago above 1500 m a.s.l., comprises an area of about 40 km 2. The whole area previously has been called Cerro Colorado by Myers and Duellman (1982). This poorly investigated area comprises, besides Cerro Santiago, another prominent peak to the west, the Cerro Sagui, and the surrounding parts of the continental divide between them. The discovery of D. igneus increases the number of endemic vertebrate species in this region of the Serranía de Tabasará to ten ( Myers & Duellman 1982; Köhler et al. 2007; Mendelson III et al. 2008; Birdlife international 2011, Hertz et al. 2012). The potential high levels of endemism in this unprotected part of the central-Panamanian mountain range is a reason important enough to create the first protected area for the mountains of the Comarca Ngöbe-Buglé, especially when considering that between 1992 and 2000 the Comarca Ngöbe-Buglé lost about 21.8% of its forest, which amounts to the highest deforestation rate in Panama (ANAM 2009).

Figures

FIGURE 3. Holotype (MVUP 2301) of Diasporus igneus from Llano Tugrí.

FIGURE 4. Ventral and dorsal view of the holotype of Diasporus igneus (MVUP 2301).

FIGURE 5. Ventral surfaces of right hand and foot of the holotype of Diasporus igneus (MVUP 2301).

FIGURE 6. Oscillogram (upper) and spectrogram (lower) of the advertisement call of the holotype of Diasporus igneus recorded at Llano Tugrí (MVUP 2301).