Noblella worleyae, Reyes-Puig & Maynard & Trageser & Vieira & Hamilton & Lynch & Culebras & Kohn & Brito & Guayasamin, 2020

Reyes-Puig, Carolina, Maynard, Ross J., Trageser, Scott J., Vieira, José, Hamilton, Paul S., Lynch, Ryan, Culebras, Jaime, Kohn, Sebastián, Brito, Jorge & Guayasamin, Juan M., 2020, A new species of Noblella (Amphibia: Strabomantidae) from the Río Manduriacu Reserve on the Pacific slopes of the Ecuadorian Andes, Neotropical Biodiversity 6 (1), pp. 162-171 : 164-168

Noblella worleyae new species Figure 2–6

Publication LSID: urn:lsid:zoobank.org:pub:04BB1FF5-A8BD-43E4-BE10-F2BE767ACFE3

Taxonomic act LSID: urn:lsid:zoobank.org:act:A9FF401F-BF55-4837-AAB2-4BA38B00000A

Proposed standard English name. Worley´s Leaf Frog Proposed standard Spanish name. Cutín Noble de Worley

Holotype

ZSFQ 551 ( Figures 3–4 ), adult female, collected at Río Manduriacu Reserve (0.312057°N, 78.854330°W; 1184 m, Figure 2 ), Cantón Cotacachi, Imbabura Province, by Ross Maynard, Paul S. Hamilton, Scott J. Trageser and José Vieira on 8 February 2018.

Paratypes (4 males, 2 females). ZSFQ 552 , adult female, collected at Río Manduriacu Reserve (0.314256°N, 78.865672°W; 1597 m), Cantón Cotacachi, Imbabura province, Ecuador, by Ross Maynard and Paul S. Hamilton on January 29 th, 2018 ; ZSFQ 550 , adult male, collected at Río Manduriacu Reserve (0.317069°N, 78.870297°W; 1701 m), Cantón Cotacachi, Imbabura province, Ecuador, by Ross Maynard, Paul S. Hamilton, and José Vieira on 11 February 2018 ; ZSFQ 345 , adult male, collected in the Río Manduriacu Reserve , Cantón Cotacachi, Imbabura province, Ecuador (0.310502°N, 78.856872°W; 1203 m), by Ross Maynard and Paul S. Hamilton on October 19 th, 2016 ; ZSFQ 2502 , 2504 adult males, collected at Río Manduriacu Reserve (0.309800°N, 78.857298°W; 1206 m), Cantón Cotacachi, Imbabura province, Ecuador, by Jorge Brito M., Jaime Culebras, and Sebastián Kohn on 9 April 2017 ; ZSFQ 2503 adult female, collected at Río Manduriacu Reserve (0.310643°N, 78.856117°W; 1222 m), Cantón Cotacachi, Imbabura province, Ecuador, by Jorge Brito M., Jaime Culebras, and Sebastián Kohn on 10 April 2017 .

Generic placement

The new species is placed in the genus Noblella based on morphological and molecular features. The taxon is recovered as a close relative of other Noblella species ( Figure 1 ) and also matches the diagnosis of Noblella by Hedges [ 5], as follows: head no wider than body; cranial crests absent; tympanic membrane differentiated (except in N. duellmani ); dentigerous processes of vomers absent; terminal discs on digits not or slightly expanded; discs and circumferential grooves present (except in N. naturetrekii and N. worleyae sp. nov.); distal phalanges narrowly T-shaped; Finger I shorter than, or equal in length to, Finger II; most species with phalangeal reduction in Finger IV (two phalanges in N. carrascoicola , N. lochites , N. myrmecoides , N. personina , N. peruviana , N. madreselva , N. naturetrek , and N. ritarasquinae ); Toe III shorter than Toe V (except in N. naturetrekii and N. worleyae sp. nov.); tips of at least Toes III–IV acuminate; subarticular tubercles not protruding; dorsum pustulate or shagreen; venter smooth; SVL less than 22 mm.

Diagnosis

The new species ( Figures 3–6 ) presents the following characteristics: (1) skin of dorsum finely shagreen; (2) tympanic annulus and membrane visible externally, supratympanic slightly visible; (3) snout rounded in dorsal and lateral view (eye-nostril distance 55% of eye diameter, Figure 3 ); (4) dentigerous processes of vomers absent; (5) fingers not expanded distally, tips of Fingers I and IV slightly acuminate, Fingers II and III acuminate, without papillae ( Figure 3 ); Finger I shorter than Finger II ( Figure 3 ); nuptial pads not visible; circumferential grooves absent; (6) distal phalanges slightly T-shaped; phalangeal formula of hands: 2, 2, 3, 3 ( Figure 6 ); (7) supernumerary palmar tubercles present, mostly at the base of the digits; subarticular tubercles rounded, proximal tubercles prominent; diminutive rounded ulnar tubercles present; (8) one elongated and subconical tarsal tubercle, two tarsal tubercles (inner tubercle 2–2.5x the size of the outer), small pigmented supernumerary tarsal tubercles, toes slightly expanded and slightly acuminate on Toes I and V, and cuspidate tips on Toes II–IV, papillae absent ( Figure 3 ); (9) Toe V shorter than Toe III, distal portions of circumferential grooves present on Toes II–V, phalangeal formula of feet: 2, 2, 3, 4, 3 ( Figure 6 ); (11) in life, dorsum brown to dark brown and densely splashed with light brown, brownish-gray, or turquoise, presence of a middorsal line continuing along the posterior lengths of hind legs cream to light brown; flanks light brown to dark brown with scattered irregular white to turquoise marks; venter yellowish-cream with minute speckling; throat with irregular brown to homogeneously brown marks ( Figure 5 ); (12) female SVL 18.1–19.1 mm (n = 3, mean = 18.7); male SVL 15.5–17.9 mm (n = 4, mean = 16.6).

Comparisons

Noblella worleyae is closely related and morphologically similar to N. coloma . Nevertheless, distal phalanges of the feet and hands of the new species are only slightly expanded laterally, as opposed to a distinct T-shape in N. Coloma [ 9], Figure 6 ). Moreover, the new species has a yellowish-cream venter with minute speckling (venter orange with minute brown and white spots in N. coloma ), throat with irregular brown marks to homogeneously brown, and lacks suprainguinal marks (present in N. coloma ).

Other species of Noblella that have three phalanges on Finger IV are N. duellmani [ 30], N. heyeri [ 10], N. lynchi [ 31], N. pygmaea [ 32], and N. thiuni [ 33]. All of them, except N. heyeri , are restricted to the Amazonian slopes of the Andes. Moreover, N. worleyae has a tympanic annulus and membrane visible externally (absent in N. duellmani , tympanic membrane not differentiated in N. thiuni ), dorsum finely shagreen (smooth in N. heyeri , pustular in N. lynchi , and tubercular in N. pygmaea ).

Noblella worleyae can be distinguished from N. carrascoicola [ 34], N. lochites [ 35], N. losamigos [ 36], N. myrmecoides [ 35], N. personina [ 37], N. peruviana [ 38], N. madreselva [ 39], N. naturetrekii [ 4], and N. ritarasquinae [ 40] by having three phalanges on Finger IV instead of two. Additionally, as mentioned before, N. worleyae , N. coloma , and N. heyeri are the only species in the genus found on the Pacific slope of the Andes.

Description of the Holotype

Adult female (ZSFQ 551); head longer than wide; snout round in dorsal and lateral views; canthus rostralis straight; loreal region slightly concave; upper eyelid 47% of interorbital distance; eye-nostril distance 66% of eye diameter; tympanum visible externally, tympanic membrane differentiated from surrounding skin; supratympanic fold slightly visible. Dentigerous processes of vomers absent. Skin of dorsum finely shagreen; venter smooth; few diminutives rounded ulnar tubercles; palmar tubercle oval, about 0.5x the size of thenar tubercle; supernumerary palmar tubercles present, mainly at base of digits; proximal subarticular tubercles prominent, rounded; fingers not expanded distally, tips of Fingers I and IV slightly acuminate, Fingers II and III acuminate, without papillae, circumferential grooves absent; relative lengths of fingers I <II <IV <III.

One elongated and subconical tarsal tubercle,two tarsal tubercles (inner tubercle 2 x the size of external); proximal subarticular tubercles well defined;small pigmented supernumerary tubercles. Toes slightly expanded and slightly acuminate on Toes I and V, cuspidate tips on Toes II–IV, distal portions of circumferential grooves visible; relative lengths of toes I <II <V <III <IV. For measurements of type series (mm) see Table 1.

Color of holotype in life

Dorsum brown,densely splashed with light brown; cream middorsal line continued along posterior lengths of hind legs; flanks light brown with scattered irregular white marks; venter yellowish-cream with minute speckling; throat with big irregular brown marks. Iris reddishbrown with some dark brown reticulations.

Color of holotype in ethanol ( Figure 4 )

Dorsum brown (flecked with white by preservation effects and manipulation);cream middorsal stripe, extending from scapular level to cloaca and then along the posterior surface of hind limb. Sides of head homogeneously dark brown, labial bars absent, with a faded post-tympanic fringe; flanks flecked with cream. Venter and ventral surfaces of legs white with scattered diminutive brown dots; throat brown with some irregular white marks. Forelimbs ventrally brown with a longitudinal white stripe along ulna, dorsally brown. Hind limbs like dorsum.

Variation of color patterns ( Figure 4–5 )

Dorsal surfaces are predominately brown (ZSFQ 550) to dark brown (ZSFQ 2502), densely splashed with light brown (ZSFQ 550, 552), brownish-gray (ZSFQ 2502), or turquoise (ZSFQ 2504), with or without a cream to light brown middorsal line continuing along the posterior edge of hindlimbs. Flanks light brown (ZSFQ 550) to dark brown (ZSFQ 2502–2504) with scattered irregular marks white (ZSFQ 550–552) to light turquoise (ZSFQ 2502–2504). Venter yellowish-cream with minute speckling; throat with irregular brown marks (ZSFQ 550) to homogeneously brown (ZSFQ 345, 551, 552, 2502–2504).

In preservative, dorsum dark brown, with a cream middorsal line continuing along the posterior edge of hindlimbs; middorsal line weakly defined in ZSFQ 550. Venter cream (ZSFQ 550–551, 2502) to brownish cream (ZSFQ 552, 2504); throat brown or cream with brown marks (ZSFQ 550).

Osteology of hands and feet

The hand and foot phalangeal formula are standard: 2-2-3-3 and 2-2-3-4-3, respectively ( Figure 6 ). The relative length of fingers is: I <II <IV <III, and that of toes is: I <II <V <III <IV. The carpus is composed of a radiale, ulnare, Carpal 1, and a large postaxial element assumed to represent a fusion of Carpals 2, 3, and 4 ( Figure 6 ). The prepollex is composed of one proximal bone and an elongated distal cartilage.The terminal phalanges are slightly T-shaped. The prehallux is represented by a small, rounded, proximal bone, and a distal irregular element ( Figure 6 ).

Call description ( Figure 7 )

Advertisement calls were recorded 22:00 h on 9 April 2017 (air temperature not recorded). Adult male ZSFQ 2502 (recording code: LBE-C-049). The call sounds like a short chirp. Each call is composed by a single short, pulsed note, with a duration of 0.032 –0.044 s (mean = 0.039 ± 0.005; n = 4). Each note has about 10 to 15 pulses, which are difficult to differentiate. Time between calls is 22.5– 31.7 s (mean = 26.6 ± 4.681; n = 3). The dominant frequency is located at a relatively wide range at 3,363 –4,172 Hz. One harmonics is present at 7,399 –7,695 Hz (n = 4).

Distribution and Natural History

Noblella worleyae is a leaf litter specialist and has only been found in either primary forest or moderately disturbed old growth secondary forest. It has been recorded from six nearby localities within the Río Manduriacu Reserve, Cantón Cotacachi, Imbabura province, Ecuador, at elevations between 1,184 m and 1,701 m ( Figure 2 ). Surveys conducted on the east side of the Río Mandiracu (opposite from the reserve) as well as those in and around the community of Santa Rosa de Manduriacu (ca. 3 km south of Río Manduriacu Reserve boundary) have yielded no records, although survey effort outside of the reserve is less extensive than that within the reserve. We have made eight field trips between 2012 and 2019, with 59 effective field days, with an average of five people actively searching for amphibians and we have been able to find a total of seven individuals. The new species seems to be endemic to this region, which is an area with high diversity and endemism of anurans [ 14, 41]. The habitat ecosystem corresponds to Low Montane Evergreen Forest of western slopes of the Andes [ 42]. The total restricted area that covers these localities is 389,248 m 2.

Noblella worleyae is one of the few diurnal anurans at the Río Manduriacu Reserve. Calls were frequently heard from dawn (6:00 h) to dusk (19:00 h), but frogs stop vocalizing when approached.Individuals were found in areas with dense leaf litter and other decaying material, and at the base of large trees. The species is evasive and individuals quickly immersed between leaves and roots as an escape method. The new species is one of the more abundant amphibians at Río Manduriacu Reserve, as groups of individuals were frequently heard calling by day throughout much of the sloped reserve during expeditions. In fact, during a morning survey (6h20 am) a total of 13 males were heard calling along a 100-m transect (JBM, field notes). The new species did not call with heavy rain. During sampling days in April 2017, air temperature inside the forest was 12–26°C (thermometer placed 120 cm above ground level at the base of a tree). Individuals have also been observed after sunset while conducting night transects, as sampling in October 2016, and January– February, 2018, yielded eight records between 20:00 and 23:05 h. However, these individuals were presumably flushed from their resting place within the leaf litter as surveyors passed by.

Etymology

The specific name is a noun in the genitive case and is a patronym for Dr. Elisabeth K. Worley (1904–2004), Professor of Marine Biology at Brooklyn College, naturalist, science communicator, educator, and mentor.

Discussion

Our phylogeny shows similar relationships within the genus Noblella as those inferred in previous studies [ 4, 6 – 8]. Noblella is a non-monophyletic taxon, as the genera Noblella and Psychrophrynella are nested and because the northern Noblella do not share the most recent common ancestor with the southern clade of Noblella and Psychroprynella. Further studies are necessary to solve the polyphyly of the genus, especially with the inclusion of genetic topotypical material of Noblella peruviana and Psychrophrynella bagrecito . The description of this new species adds to our understanding of the phylogenetic relationships within Noblella and the changes needed to render Noblella monophyletic.

The description of this new frog species from the Río Manduriacu Reserve is yet another study demonstrating the importance of the reserve as a critical conservation area for amphibian diversity [ 14]. However, the expansion of large-scale mining concessions in northwestern Ecuador is a major threat to the future of this region [ 14, 43]; illegal mining activities have been conducted within Río Manduriacu Reserve, as well as nearby areas [ 14, 44]. The western Andean slopes of Ecuador is comprised of important microregions of small vertebrate endemism, which are restricted to areas with good-quality forest and with little to no anthropogenic activity (e.g [ 14, 45, 46, 47]). Thus, projects that threaten these Andean forests must be regulated and authorized within the framework of the Ecuadorian Constitution. Moreover, a program for conservation actions aiming to protect the unique biodiversity is also needed for the Ecuadorian Andes. Such an approach is already being advanced, mostly with the participation of non-profit institutions that aim to protect priority and vulnerable forests for biodiversity conservation, such as the EcoMinga Foundation [ 4, 14,15]. Nonetheless, ongoing research, long-term conservation funding, and assurance that protected areas will not be undermined by extractive companies are necessary to ensure the survival of species with high endemism such as N. worleyae and its fragile habitats.

Figures

Figure 1. Phylogeny of Noblella (gray box) showing the relationships of Noblella worleyae sp. nov. The phylogeny was based on mitochondrial (16S) DNA sequences. For each individual, the corresponding museum catalog number (when available) and GenBank accession number are shown.

Figure 2. Map of Ecuador showing the location of Río Manduriacu Reserve, the type locality (red triangle) of Noblella worleyae sp. nov.

Figure 3. Noblella worleyae sp. nov., holotype, ZSFQ 551, adult female, SVL = 18.1 mm. (A) palmar surface; (B) plantar surface; (C) dorsal view of the head; (D) lateral view of the head. Illustrations by Carolina Reyes-Puig.

Figure 4. Color variation of preserved Noblella worleyae sp. nov. (A, F) ZSFQ 551, holotype, adult female, SVL = 18.1 mm; (B, G) ZSFQ 552, paratype, adult female, SVL = 19.1 mm; (C, H) ZSFQ 550, paratype, adult male, SVL = 17.3 mm; (D, I) ZSFQ 2502, paratype, adult male, SVL = 15.9 mm; (e, j) ZSFQ 2504, paratype, adult male, SVL = 15.5 mm.

Figure 5. Dorsal and ventral color patterns of Noblella worleyae sp. nov. in life. (A, D) Dorsal pattern and ventral pattern of ZSFQ 2504, paratype, adult male, SVL = 15.5 mm; (B, E) dorsal pattern and ventral pattern of ZSFQ 2502, paratype, adult male, SVL = 15.9 mm; (C, F) dorsal pattern and ventral pattern of ZSFQ 550, paratype, adult male, SVL = 17.3 mm; (G, J) dorsal pattern and ventral pattern of ZSFQ 552, paratype,adult female, SVL = 19.1 mm; (H, K–L) dorsal pattern and ventral pattern of ZSFQ 550, paratype, adult male, SVL = 17.3 mm; (I) dorsal pattern of an uncollected specimen. Photographs by Jaime Culebras (a, b, d, e), José Vieira (c, f), Ross Maynard (g–k) and Scott Trageser (l).

Figure 6. Right hand (A) and foot (B) in dorsal view of Noblella worleyae sp. nov. ZSFQ 345, paratype, adult male, SVL = 17.9 mm.

Figure 7. Call of the paratype (ZSFQ 2502) of Noblella worleyae sp. nov. The recording was made at 22:00 on April 9th, 2017 (air temperature not recorded). (A) Amplitude; (B) Frequency.