Hyloscirtus sethmacfarlanei, Reyes-Puig & Recalde & Recalde & Koch & Guayasamin & Cisneros-Heredia & Jost & Yánez-Muñoz, 2022

Reyes-Puig, Juan P., Recalde, Darwin, Recalde, Fausto, Koch, Claudia, Guayasamin, Juan M., Cisneros-Heredia, Diego F., Jost, Lou & Yánez-Muñoz, Mario H., 2022, A spectacular new species of Hyloscirtus (Anura: Hylidae) from the Cordillera de Los Llanganates in the eastern Andes of Ecuador, PeerJ 10, pp. 1-34 : 7-25

publication ID

https://doi.org/ 10.7717/peerj.14066

DOI

https://doi.org/10.5281/zenodo.7595860

persistent identifier

https://treatment.plazi.org/id/D8772703-152B-2A01-6EC3-FA26FD93F948

treatment provided by

Valdenar

scientific name

Hyloscirtus sethmacfarlanei
status

sp. nov.

Hyloscirtus sethmacfarlanei sp. nov.

Proposed standard Spanish name: Rana de torrente de Seth MacFarlane Proposed standard English name: Seth MacFarlane’ s torrent frog urn:lsid:zoobank.org:pub:4BF8C735-F06C-41AE-B130-EE41130535CC

Holotype ( Figs. 3 View Figure 3 , 4 View Figure 4 ). DHMECN 14416 , adult gravid female, collected in the Machay Reserve of Fundacion EcoMinga , Cerro Mayordomo (1.370204 S, 78.267943 W, 2,970 m), Rio Verde parish , Baños township , Tungurahua province, Republic of Ecuador, on 17 March 2018, by Darwin Recalde, Fausto Recalde, Santiago Recalde, and Jordy Salazar. GoogleMaps Paratypes ( Figs. 5–8 View Figure 5 View Figure 6 View Figure 7 View Figure 8 ). DHMECN 14549 , juvenile, sex undetermined, without differentiation of external and internal sexual characters, collected at the type locality on 19 October 2018, by Fausto Recalde, Santiago Recalde, Darwin Recalde and Jordy Salazar; DHMECN 17554 , juvenile sex undetermined, no differentiation of external and internal sexual characters, collected at the type locality on 30 May 2022, by Fausto Recalde, Luis Recalde, and Santiago Recalde.

Generic placement. We assign the new species to the genus Hyloscirtus Peters, 1882 , defined according to Faivovich et al. (2005) and Rojas-Runjaic et al. (2018), and to the H. larinopygion group (sensu Duellman & Hillis, 1990; Faivovich et al., 2005), according to its phylogenetic position ( Fig. 1 View Figure 1 ) and morphological traits such as wide dermal fringes on fingers and toes, hands and legs with large terminal discs and a reduced membrane, adults characterized by a snout vent length>60 mm, and dark overall skin color contrasting with bright color patterns.

Diagnosis. Hyloscirtus sethmacfarlanei sp. nov. is a member of the Hyloscirtus larinopygion group as diagnosed by Duellman & Hillis (1990), Faivovich et al. (2005) and Weiens et al. (2005), and differs from other members of the group by the following combination of characters: discs of digits narrow; fleshy calcar present cloacal ornamentation with two thick well-defined parallel paracloacal grooves; a well-defined supracloacal fold reaching the vent; skin surrounding cloaca strongly areolate and granular; anterior border of sphenethmoid not in contact with nasal; nasal not in contact with maxilla; frontoparietals rugose; vomers not in medial contact, and with 12‒13 tooth loci; 54‒56 maxillary tooth loci; 10‒11 premaxillary tooth loci; zygomatic ramus of squamosal slightly longer than otic ramus, and otic ramus not in contact with prootic.

The adult female, in its reproductive stage with internal sexual characters defined, is further characterized by black ground color covered with large bright red spots on both the dorsal and ventral surfaces, and red tips on all digits.

Description of holotype ( Figs. 3 View Figure 3 , 4 View Figure 4 ). Adult female, SVL 72.0 mm. Body slender, head rounded in dorsal view, longer than wide (head length 113% of head width); width of upper eyelid 72% of the interorbital distance; texture of the dorsal surface of the head rough, including the eyelids; snout truncate in dorsal and lateral views; eye-nostril distance slightly less than the diameter of the eye; canthus rostralis short and slightly rounded, loreal region slightly concave; internarial region flat and slightly depressed; top of head slightly concave; nostrils oval and slightly protuberant, directed laterally; eyes large and protuberant, 25% of head length; interorbital region concave; eye diameter 1.8 times larger than the diameter of the tympanic ring; supratympanic fold well-defined, directed obliquely from the posterior border of the eye, covering the dorsal edge of the tympanum, extending back to the upper shoulder; tympanum and tympanic ring evident and round, 57% of eye diameter, separated from the eye by a distance 1.6 times larger than the diameter of the tympanum.

Anterior and posterior extremities slim. Relative length of fingers I <II <IV <III; fingers with large oval disks slightly wider than finger; subarticular tubercles simple and enlarged, round and prominent; multiple round and oval supernumerary tubercles present; thenar tubercle large and flat, oval and elongated; palmar tubercle asymmetric with a slightly heart-shaped outline; prepollex absent; glandular nuptal pad covering the outer margin of Finger I; fingers long with interdigital webbing basally and with fleshy lateral fringes on all fingers.

Hind limbs long and slender, tibia length 46% of SVL; foot length 46% of SVL; heel tubercles large and round in outline; inner tarsal fold absent; large rounded to slightly oval subarticular tubercles in all fingers, supernumerary foot tubercles rounded, low; toes long, narrower than the disc, discs not expanded; relative lengths of toes I <II <V<III <IV; inner metatarsal tubercle large, oval; outer metatarsal tubercle absent; toes with interdigital membrane, toe membrane formula: I 2-3 II 3- 2 III 3-2 IV 3-2 V ( Fig. 4 View Figure 4 ).

Body skin is finely granular, especially on flanks; inguinal glands absent; ventral skin densely areolate, less so towards the throat. Supracloacal flap transversal, well-defined, with supracloacal fold present, reaching the level of the vent, with two paracloacal folds; skin around the cloaca strongly areolate and granular ( Figs. 9 View Figure 9 , 10 View Figure 10 ). Choana large and oval, notably separated from each other and perpendicular to the floor of the mouth; dentigerous processes of vomers transverse, with vomerine teeth numbering 9‒10; tongue wide and rugose, slightly rounded, partially attached to the floor of the mouth.

Coloration of holotype in life ( Figs. 5–8 View Figure 5 View Figure 6 View Figure 7 View Figure 8 , 11 View Figure 11 ). Entire dorsal and ventral surfaces of the head, body, and limbs black with large bright red round to oval spots scattered over the whole body, including the tips of the digits; spots 3‒4 mm in diameter on dorsal surface of body and 5‒10 mm long on ventral surface and throat, more elongated on the extremities and flanks. Iris light grayish with fine dark reticulations, while the nictitating membrane, revealed in defense and at rest, is well-developed, black in color, with irregular red reticulations.

Coloration of holotype in preservative (~70% ethanol) ( Fig. 3 View Figure 3 ). Mainly black background; the red spots in life fade to yellowish-white or white; ventral surfaces and throat grayish black with scattered irregular white elongated spots; palms of hands and feet grayish.

Measurements of the holotype (in mm). SVL = 72.0; HL= 22.9; HW = 20.2; EW = 6.0; IOD = 8.3; IND = 5.2; END = 5.4; ED = 5.7; TD = 3.2; HAL = 25.2; TL = 33.3; FEL = 26.1; FL = 33.4.

Note:

SVL, snout-vent length; HL, head length; HW, head width; EW, upper eyelid width; IOD, interorbital distance; IND, inter-nostril distance; END, eye-nostril distance; ED, eye diameter; TD, tympanum diameter; HAL, hand length; TL, tibia length; FEL, femur length; FL, foot length.

Measurements of the paratypes. See Table 2 View Table 2 .

Osteology of the preserved holotype ( Figs. 12–15 View Figure 12 View Figure 13 View Figure 14 View Figure 15 ). Coloma et al. (2012) provide a detailed description of the osteology of the H. larinopygion group. In order to avoid redundancy, in the following we describe only those osteological features of the holotype of H. sethmacfarlanei sp. nov. where we found differences from the other species.

Skull ( Figs. 11 View Figure 11 , 12 View Figure 12 ). The anterior border of the sphenethmoid is not in contact with the nasal; the nasal is not in contact with the maxilla; the frontoparietals are rugose; the paired vomers bear 12‒13 tooth loci and are not in contact medially; there are 54‒56 tooth loci on each maxilla and 10‒11 tooth loci on each premaxilla; the zygomatic ramus of the squamosal is slightly longer than the otic ramus, and the latter is not in contact with the prootic.

Posteromedial processes of the hyobranchium ( Fig. 15 View Figure 15 ). The posteromedial processes of the hyobranchium are paired ossified structures, longer than broad, the anterior portion with triangular “head-like” shape, and a posterior elongated stem.

Tadpole. Not known.

Advertising call. Not known.

Variation ( Figs. 5 View Figure 5 , 6 View Figure 6 , 10 View Figure 10 and 11 View Figure 11 ). Standard measurements from the three collected individuals are shown in Table 2 View Table 2 . The three known juveniles (DHMECN 14549, DHMECN 17554, and the uncollected individual) share the distinctive cloacal ornamentation and skin texture of the holotype, but differ from the female holotype as follows: sexual characters not clearly evident (based on the observation of internal anatomy); in life the dorsal surface with irregular marks mustard yellow heavily stippled with black, especially on flanks and lower back (DHMENC 14549), or a variagated yellow-orange pattern (DHMECN 17554); nictitating membrane dotted with mustard yellow on a gray background (DHMENC 14549) or orange on a black background (DHMECN 17554); extremities orange banded (DHMENC 14549) or spotted (DHMECN 17554), on a grayish black to black ground; flanks black with orange reticulations and irregular spots; throat marbled with irregular orange or yellowish patches with orange tones on a grayish black or black ground; belly and ventral surfaces of the extremities grayish black with irregular sparse diffuse light orange or whitish-yellow patches (DHMENC 14549) or solid orange (DHMENC 17554); palms of hands and feet black with diffuse light orange spots. The uncollected juvenile had a mainly yellow dorsal coloration, with diffuse blackish spots scattered on the flanks and hidden surfaces of the arms and between the fingers, whose tips were yellow. The belly is light cream with diffuse blackish spots. We noted rapid temporal chromatic changes in the juvenile individuals, from dull yellow to orange tones. As observed in other members of the Hyloscirtus larinopygion species group, changes in color pattern may be characteristic of different stages of development and related to ontogenic changes ( Coloma et al., 2012). The juveniles all shared the same distinctive cloacal ornamentation as the adult ( Fig. 10 View Figure 10 ).

Comparison with similar species ( Figs. 8 View Figure 8 , 9 View Figure 9 , Table 3 View Table 3 ). The black and red pattern of the female of the new species is most similar to the patterns of Hyloscirtus pantostictus (Duellman & Berger, 1982) , from extreme northeastern Ecuador, and H. princecharlesi Coloma et al. (2012), from the Pacific slopes of the Andes of northwestern Ecuador.

The new species differs from these in having both the dorsal and ventral surfaces spotted with red (vs ventral surface without red spots in H. pantostictus and H. princecharlesi , Fig. 8 View Figure 8 ), the cloacal ornamentation ( Fig. 9 View Figure 9 ) consisting of a well-defined supracloacal fold reaching next to the vent and the presence of a paracloacal fold (vs reduced supracloacal fold, without paracloacal fold, not contacting the side of the vent, in H. pantostictus , and supracloacal fold defined, reaching the border of the vent, with paracloacal fold thick, in H. princecharlesi ), and strongly areolate skin texture (vs smooth in H. pacha , H. staufferorum, and H. larinopygion ). The female of the new species also differs from these two species in having red discs on the tips of all digits (vs yellow discs in H. pantostictus and grayish discs in H. princecharlesi ).

The new species’ red discs are shared with H. lindae (Duellman & Altig, 1978) from the eastern Andes , but H. lindae does not have red spots on its dorsal surface and does not have a thick supracloacal fold close to the side of the vent ( Fig. 9 View Figure 9 ). Juveniles assigned to H. sethmacfarlanei sp. nov. have a pattern similar to those of H. princecharlesi and H. larinopygion (Duellman, 1973) from northwestern slopes of the Andes . They differ from juveniles of both species in having the dorsum mottled and stippled mustard-yellow and black (vs dorsum densely spotted orange-red in H. princecharlesi , and yellowish-brown with distinctive cream bars with black interspaces in H. larinopygion ). The supracloacal fold is well-defined and reaches to the vent in H. sethmacfarlanei sp. nov. (vs faintly defined and distant from the side of the vent in H. larinopygion ). Hyloscirtus sarampiona ( Ruiz-Carranza & Lynch, 1982) from the western slopes of the Colombian Andes has dorsal surfaces orange spotted with pale olive, and further differs from the new species by having hidden areas of the limbs, flanks, palmar, plantar surfaces and discs black.

The skull of H. sethmacfarlanei sp. nov. ( Figs. 12 View Figure 12 , 13 View Figure 13 ) is generally consistent with those of the other species of the H. larinopygion group ( Coloma et al., 2012). However, there were a few differences between the new species and the species of the group studied by us or by Coloma et al. (2012). In H. sethmacfarlanei sp. nov. and H. ptychodactylus , the sphenethmoid is not in contact with the nasal, whereas these two bones are in contact in H. criptico and in H. staufferorum , they are anteriorly in contact in H. lindae and H. larinopygion , they are in contact along most of their length in H. psarolaimus , they are in contact along their entire length but with still a visible suture in H. pacha , and they are completely fused without a visible suture in H. tapichalaca . In H. sethmacfarlanei sp. nov.,

H. lindae , H. pacha , and H. larinopygion the nasal is not in contact with the maxilla, whereas it is in contact with the maxilla in H. criptico , H. pantostictus , H. ptychodactylus , H. staufferorum , and H. tapichalaca . The frontoparietals of H. sethmacfarlanei sp. nov. are comparatively more rugose than in other species of the group ( Fig. 12 View Figure 12 ). In contrast to H. pantostictus and H. staufferorum , in H. sethmacfarlanei sp. nov., H. criptico , H. lindae , H. pacha , H. psarolaimus , H. ptychodactylus , H. larinopygion , and H. tapichalaca the otic ramus of the squamosal is not in contact with the prootic. In H. sethmacfarlanei sp. nov. the zygomatic ramus of the squamosal is only slightly longer than otic ramus, whereas it is moderately longer than the otic ramus in H. pacha and H. staufferorum , and distinctly longer than the otic ramus in H. criptico , H. lindae , H. pantostictus , H. ptychodactylus , H. larinopygion , and H. tapichalaca . In contrast to H. criptico , H. larinopygion , and H. tapichalaca , in H. sethmacfarlanei sp. nov., H. lindae , H. pantostictus , H. ptychodactylus , and H. staufferorum the vomers are not in medial contact. Hyloscirtus sethmacfarlanei sp. nov. has 12‒13 vomerine tooth loci, 54‒56 tooth loci on each maxilla, and 10‒11 tooth loci on each premaxilla, whereas we counted 14 vomerian tooth loci, 59‒60 maxillary tooth loci, and 11‒12 premaxillary tooth loci in H. lindae , 14 vomerine tooth loci, 52‒59 maxillary tooth loci, and 9 premaxillary tooth loci in H. pacha , 13‒14 vomerine tooth loci, 52‒53 maxillary tooth loci, and 9 premaxillary tooth loci in H. psarolaimus , 11‒12 vomerine tooth loci, 56 maxillary tooth loci, and 12 premaxillary tooth loci in H. larinopygion , and only 5‒6 vomerine tooth loci, 31‒33 maxillary tooth loci, and 5‒6 premaxillary tooth loci in H. tapichalaca .

In the new species the posteromedial processes of the hyobranchium possess a triangular shaped anterior portion, and a shorter posterior portion compared with the other species shown in Fig. 14 View Figure 14 , which have an external round border and an internal spine-like border. In H. lindae , H. psarolaimus and H. pacha , the anterior portions have rounded external and internal borders. In H. tapichalaca it is broad and “shell-like” in its anterior border.

There are no relevant differences between the forelimb bones of the new species and those of the other species in the group, with the exception of male specimens of H. tapichalaca , which have a greatly enlarged prepollex (Kizirian, Coloma & Paredes-Recalde, 2003; this study) compared to the other species of the H. larinopygion group.

Distribution ( Fig. 16 View Figure 16 ). Hyloscirtus sethmacfarlanei sp. nov. is known at the moment only from the type locality in Fundación EcoMinga’ s Machay Reserve, Cerro Mayordomo, 2,970 m altitude, in the eastern cordillera of the central Ecuadorian Andes , in the northern side of the upper Rio Pastaza watershed near the southern border of Llanganates National Park in the province of Tungurahua.

Natural history. The type locality consists of dwarf open mossy forest, covered with bryophytes and epiphytes, and saturated with humidity. All four known individuals of this species were found on a single narrow mountain ridge, in bromeliads of the genus Guzmania growing within 60–90 cm above the ground ( Fig. 17 View Figure 17 ). The holotype is an adult gravid female with a mass of eggs in early stage of development in March 2018. Adult male, tadpole and advertisement call remain unknown.

There is some evidence that the striking coloration of the adult female of H. sethmacfarlanei sp. nov. could be aposematic. The frog’ s discoverer (Darwin Recalde), after briefly handling the frog, noticed an unpleasant tingling sensation down his arm, not restricted to the area which had contacted the frog; the sensation lasted several hours.

Fausto Recalde, who had shorter contact with the frog, developed similar but

shorter-lasting symptoms; these reactions were not observed after handling the juveniles. During handling of the holotype specimen in the museum, it emitted a white exudation on dorsal surfaces with a distinctive odor similar to diluted contact cement. Additionally, when tissue was taken from the liver, dark blackish-colored blood was observed.

The bright yellow uncollected juvenile slept during the day, and when disturbed, it adopted a defensive ball-like position, as observed in other species of the H. larinopygion group (Kizirian, Coloma & Paredes-Recalde, 2003; Bejarano-Muñoz, Perez Lara & Brito Molina, 2015 ). Thus the juvenile coloration may also advertise distastefulness.

Nocturnal surveys done by our team in the habitat of Hyloscirtus sethmacfarlanei sp.

nov. revealed three sympatric anuran species: two undescribed Pristimantis species and one species of the Pristimantis buckleyi complex.

Conservation Status. All four known individuals are known only from the same few square meters of ridgeline, but the area is poorly studied and inaccessible because of steep topography. We suggest the IUCN category Data Deficient (DD) for this species.

Etymology. The specific epithet sethmacfarlanei is a patronym in honor of Seth MacFarlane, American writer, director, producer, actor, artist, musician and conservationist, with an outstanding passion for science, biodiversity and the natural world.

Table 2 Morphological measurement of the type series of Hyloscirtus sethmacfarlanei sp. nov.

Morphological Measurements Holotype adult female DHMECN 14416 Paratype juvenile DHMECN 14549 Paratype juvenile DHMECN 17554
SVL 72.0 46.5 53.9
HL 22.9 16.1 19.5
HW 20.2 15.6 18.4
EW 6.0 4.6 6.7
IOD 8.3 5.2 4.6
IND 5.2 3.7 4.8
END 5.4 3.5 3.3
ED 5.7 4.1 5.4
TD 3.2 2.0 3.1
HAL 25.2 16.7 21.6
TL 33.3 24.3 29.1
FEL 26.1 20.8 26.4
FL 33.4 22.7 28.1

Table 3 Cloacal ornamentation and presence of calcar on the heel in Ecuadorian species of the Hyoscirtus larinopygion group.

Reference and voucher specimens based for cloacal ornamentation Species Supracloacal fold Vent- supracloacal fold relation Paracloacal fold Cloacal texture Calcar on the heel
This work (DHMECN 14416) Hyloscirtus . sethmacfarlanei Defined Reaching the vent Thick, well defined Strongly, areolate and granular Present
  sp. nov.          
This work (DHMECN 12483) Hyloscirtus lindae Thick , developed, tongue like shape Reaching the border of the vent Weakly defined Densely tuberculate Absent
This work (DHMECN 12113) Hyloscirtus pacha Thick Separated from the vent Thick, well- defined Smooth Present
This work (DHMECN 3799) Hyloscirtus larinopgygion Defined Separated from the vent Absent Smooth Present
This work (DHMECN 6493) Hyloscirtus psarolaimus Weakly defined Separated from the vent Absent Little tubercles Absent
This work (DHMECN 4590) Hyloscirtus criptico Defined Separated from the vent Weakly defined Strongly granular Absent
Duellman & Coloma, 1993 (KU 217695) Hyloscirtus staufferorum Weakly defined Separated from the vent Absent Smooth Absent
Duellman & Berger, 1982 (KU190000) Hyloscitus pantostictus Well-defined Reaching the border of the vent Absent Densely tuberculate Absent
Coloma et al., 2012 (QCAZ 44893) Hyloscirtus princecharlesi Defined Reaching the border of the vent Present, thick Smooth Absent
Mueses-Cisneros & Anganoy-Criollo, 2008 (ICN 53804) Hyloscirtus tigrinus Thick Separated from the vent Present Smooth with granular tubercles Present
Duellman & Hillis, 1990 (KU 209780) Hyloscirtus ptychodactylus Defined Reaching the border of the vent Present Smooth Present
Kizirian, Coloma & Paredes-Recalde, 2003 (QCAZ 65235) Hyloscirtus tapichalaca Defined Reaching the border of the vent Present, thick Smooth Absent
Almendáriz et al., 2014 (QCAZ 68646) Hyloscirtus condor Thick Reaching the border of the vent Absent Smooth Present
Ron et al., 2018 (QCAZ 40331) Hyloscirtus hillisi Well-defined Separated from the vent Present, thin Areolate Absent

Kingdom

Animalia

Phylum

Chordata

Class

Amphibia

Order

Anura

Family

Hylidae

Genus

Hyloscirtus

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