Tuesday, December 14, 2021

[Herpetology • 2021] Echinosaura fischerorum • A New and very Spiny Lizard (Squamata: Gymnophthalmidae) from the Andes in northwestern Ecuador

Echinosaura fischerorum
Yánez-Muñoz, Torres-Carvajal, Reyes-Puig, Urgiles-Merchán & Koch, 2021

Photographs by J. P. Reyes-Puig & M. A. Urgiles-Merchán

We describe a new species of Neotropical spiny-lizard of the genus Echinosaura from the Imbabura and Carchi Provinces on the western slopes of the Andes in northwestern Ecuador. The new species mostly resembles E. horrida. However, it can be distinguished from all congeners by having keeled enlarged dorsal scales forming a paired vertebral row, two paravertebral series of short oblique rows of projecting scales, and a pair of spine-like scales on temporal and nuchal regions. We also provide a detailed description of the osteology of the skull and pectoral girdle of the new species and present a phylogenetic hypothesis for Echinosaura based on three mitochondrial genes (12S, 16S, ND4) and one nuclear gene (c-mos).

Squamata Oppel, 1811

Gymnophthalmidae Merrem, 1820

Echinosaura Boulenger, 1890

Live type specimens of Echinosaura fischerorum sp. nov. showing color variation in dorsal view.
 (A) DHMECN 15208, male (Holotype); (B) DHMECN 15209, male; (C) DHMECN 15211, male; (D) DHMECN 16109, female; (E) DHMECN 16110, male.
Scale bars = 10 mm. 
Photographs by Juan P. Reyes-Puig (A, B, C); Miguel A. Urgiles-Merchán (D); Andrew Better (E).

Echinosaura fischerorum sp. nov. 
Proposed standard Spanish name: Lagartijas espinosas de los Fischer
Proposed standard English name: Fischers’ Spiny Lizards

Diagnosis. The new species can be distinguished from all congeners by the combination of the following characteristics: (1) snout pointed; (2) internasal single; (3) frontonasals paired; (4) frontal single; (5) frontoparietal paired; (6) supraoculars three, large; (7) supralabials five; (8) infralabials four; (9) postmental single; (10) chin shields enlarged, in one pair; (11) dorsum with a vertebral row of paired, enlarged, keeled scales; (12) two paravertebral series of short oblique rows of projecting scales, with scales increasing in size posteriorly on each row so that the most posterior scale of each row is a greatly enlarged, projecting spine; (13) spiny scales forming oblique lines on body flanks; (14) ventral scales squared, keeled; (15) subdigital lamellae on fourth finger 14–18; (16) subdigital lamellae on fourth toe 24–27; (17) femoral pores per hind limb in males 7–9; (18) dorsal surface of tail with two longitudinal rows of enlarged keeled scales that are more conspicuous on the anterior half of tail; (19) subcaudals per caudal segment three (anterior third of tail excluded); (20) tip of snout with creamy orange marks; (21) dorsal background dark brown with creamy orange paravertebral blotches extending onto anterior end of tail; (22) intense orange nuchal spines; (23) base of tail dorsally with a pair of pale orange blotches; (24) venter gray, marmorated with black and dark brown; (25) femoral pores yellowish cream; (26) premaxillary tooth loci 11–12; (27) maxillary tooth loci 17–18; (28) dentary tooth loci 22–23; (29) nasal bones in medial contact along most of their length; (30) postfrontal expands posteriorly to form part of the anterior border of the supratemporal fenestra.

Live specimens of six species of Echinosaura.
(A)Echinosaura fischerorum sp. nov., male (no voucher), Reserva Manduriacu, Pichincha, Ecuador; (B) E. horrida, male (DHMECN 13913), Cerro Zapallo, Esmeraldas, Ecuador;
(C) E. palmeri, male (no voucher), Timbiqui, Colombia; (D) E. brachycephala, male (QCAZ 11911), Reserva Ecológica Bosque Nublado Santa Lucía, Pichincha, Ecuador;
(E) E. keyi, male (QCAZ 8074), Reserva Otokiki, Esmeraldas, Ecuador; (F) E. orcesi, male (QCAZ 15026), Reserva Tesoro Escondido, Esmeraldas, Ecuador.
 Photographs by Mario H. Yánez-Muñoz (B); Jaime Culebras (A, C); Diego Quirola (D, E); Santiago R. Ron (F).

Distribution and Natural History: Echinosaura fischerorum sp. nov. is known from the western slopes of the Andes in northwestern Ecuador, Imbabura and Carchi Provinces, between 1,495–1,750 m (Fig. 17). All known specimen records lie in the lower montane forest ecosystem of the Mira river basin within the Dracula Reserve, a 1,136 ha private protected area managed by the Ecominga Foundation. The record from Imbabura province corresponds to a photograph by Jaime Culebras from Manduriacu Reserve, also managed by the Ecominga Foundation. Most known localities of E. fischerorum sp. nov. are in close proximity to the Ecuador-Colombia border and we expect that this species might also be present in neighboring Colombia. Most specimens were observed active among tree roots during the day and collected in pitfall traps along forest ridges near streams. Gravid females were collected in April and November. One female paratype (DHMECN 15210) contained two large oval eggs in the oviduct and several snail shells in the stomach (Fig. 16).

Etymology. The specific epithet is a patronym in honor of Beat Fischer and Urs Fischer, donors who have contributed significantly to the consolidation of the Dracula Reserve in the sectors of Peñas Blancas and El Pailón, which not only protect the populations of this new endemic species, but also important populations of threatened amphibians and reptiles of the Mira river basin.

Fieldwork in the western foothills of the Andes in northwestern Ecuador led us to the discovery of a new species of Echinosaura and increased the number of known species of this genus to eight.

Our phylogenetic analyses support the monophyly of Echinosaura fischerorum sp. nov. While its sister species E. horrida is relatively widespread in the tropical lowland rainforest of western Ecuador between sea level and ∼1,500 m, the record of E. fischerorum sp nov. from Manduriacu suggests that this species is most likely widespread between Manduriacu Reserve and Río Mira at slightly higher elevations.

Mario H. Yánez-Muñoz, Omar Torres-Carvajal, Juan P. Reyes-Puig, Miguel A. Urgiles-Merchán and Claudia Koch. 2021. A New and very Spiny Lizard (Gymnophthalmidae: Echinosaura) from the Andes in northwestern Ecuador. PeerJ. 9:e12523. DOI: 10.7717/peerj.12523