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| Macropholidus montanuccii Torres-Carvajal, Venegas & Nunes, 2020 |
Abstract
We describe a new species of Macropholidus lizard from the Andean highlands of southern Ecuador and northern Peru based on recent collections. Among other characters, the new species differs from other species of Macropholidus in having a paired series of enlarged middorsal scale rows restricted to the nape, striated dorsal scales, as well as ocelli on tail, flanks, scapular region and neck. We also present a molecular phylogeny of Cercosaurinae and genetic distances as additional evidence supporting delimitation of the new species, which is sister to M. annectens from southern Ecuador. Data on Andean orogeny and age estimates of cercosaurine lizards suggest that the Huancabamba Depression, long recognized for its dual role as a biogeographic barrier and a migration corridor, has also served as a center of origin and diversification of Macropholidus lizards.
KEYWORDS: Hemipenes, Macropholidus, South America, systematics, tropical Andes
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| Figure 2. Holotype (CORBIDI 12931; SVL = 53.5 mm) of Macropholidus montanuccii sp. nov. in dorsal (top) and ventral (bottom) views. Photographs by D. Quirola. |
Macropholidus montanuccii sp. nov.
Macropholidus sp. Torres-Carvajal et al., 2016: 70.
Suggested common name in English: Montanucci's Cuilanes.
Suggested common name in Spanish: Cuilanes de Montanucci.
Diagnosis: Macropholidus montanuccii sp. nov. can be distinguished from both M. ataktolepis and M. ruthveni by having a paired series of enlarged middorsal scale rows restricted to the nape (Figs. 2, 3; series continuous to anterior half of body in M. ataktolepis, and continuous to sacral region in M. ruthveni). From M. ataktolepis, M. montanuccii sp. nov. further differs in lacking prefrontal scales and having more (33–42, 36.78 ± 1.80) transverse rows of dorsal scales from occipital scale to posterior margin of hind limbs (29–35, 32.8 ± 1.92 in M. ataktolepis). From M. huancabambae, M. montanuccii sp. nov. differs in having shorter and striated dorsal scales (elongate and strongly keeled in M. huancabambae), and more transverse rows of dorsal scales from occipital scale to posterior margin of hind limbs (32–35, 32.2 ± 0.2 in M. huancabambae). The new species is more similar in morphology to its sister species M. annectens (Fig. 4; character states in parentheses), from which it differs in having fewer transverse rows of dorsal scales from occipital scale to posteri- or margin of hind limbs (40–48, x̄ = 42.6); fewer—21–28, 23.85 ± 1.77—transverse rows of ventral scales between collar fold and preanals (25–30, x̄ = 27.3); usually a series of black speckles forming a more or less continuous line on middorsum and onto tail (dorsum usually uniform without speckles forming lines; Fig. 4); irregular dark marks on lower lips (lower lips uniform in color); conspicuous ocelli above fore limbs, on neck, and sometimes along flanks extending onto tail (ocelli absent); distinct white dorsolateral stripe from snout to scapular region (white stripe shorter, from snout to nape or to a level above tympanum); and five or more paired, enlarged middorsal scales behind occiput (1–2).
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| Figure 4. Specimens of Macropholidus montanuccii sp. nov. (A–E) and M. annectens (F) in life. A, B: holotype CORBIDI 12931, SVL = 53.5 mm; C: paratype QCAZ 10316, SVL = 52.18; D: paratype QCAZ 10326, SVL = 44.94; E: paratype QCAZ 10292, SVL = 49.33; F: QCAZ 13870, SVL = 48.86. |
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| Figure 7. Distribution of Macropholidus annectens (green) and Macropholidus montanuccii sp. nov. (blue) in South America. Areas > 2000 m are in darker color. |
Distribution and natural history:
Macropholidus montanuccii sp. nov. is known from the highlands and Pacific slopes of the Andes in southern Ecuador and northern Peru (Fig. 7). It occurs at elevations between 1,947 and 3,078 m in the province of Loja in Ecuador and the department of Piura in Peru. The type locality lies within Cordillera de Huancabamba in northwestern Peru and corresponds to the Eastern Cordillera Real Montane Forest (Olson et al., 2001); it forms part of a patch of cloud forest of approximately 1,200 ha on the western slope of Cerro Chacas. During our field surveys in the type locality and nearby areas, M. montanuccii sp. nov. was abundant between 8:00 h and 11:00 h, both under sunny conditions and partially clouded sky with sun intervals. All individuals of M. montanuccii sp. nov. were collected active by day, foraging on the leaf litter and between the herbaceous vegetation close to the edge of trails and along road cuts. When individuals of this species were disturbed, they took refuge in the herbaceous vegetation, shrubs, and under fallen trunks or rocks. Some individuals were found inactive under fallen trunks or rocks in cloudy or rainy days.
Four females collected on February 2010 in southern Ecuador laid two eggs each, which ranged between 10.59–12.41 mm in length and 6.02–6.66 mm in width. Two gravid females collected in May 2006 in Peru contained one egg on each oviduct ranging between 4.26–6.34 mm in length and 2.85–4.25 mm in width.
Other sympatric squamates collected with Macropholidus montanuccii sp. nov. were Dipsas jamespetersi, D. oreas, Erythrolamprus albiventris, Atractus carrioni, Mastigodryas heathii, Andinosaura vespertina, Stenocercus carrioni, S. humeralis, S. limitaris, and S. ornatus.
Etymology: The specific epithet is a noun in the genitive case and is a patronym for Richard R. Montanucci, who published a seminal work on the systematics of Pholidobolus lizards in the early 1970's (Montanucci, 1973) after intensive work along the Andes of Ecuador. Richard Montanucci has dedicated his life to the study of lizards. His work on Pholidobolus lizards is of great importance for anyone interested in gymnophthalmid lizards from the Tropical Andes.
Biogeography of Macropholidus:
The Huancabamba Depression or Huancabamba Deflection has long been recognized as a major biogeographic barrier for some Andean organisms (Vuilleumier, 1969; Duellman, 1979; Cadle, 1991), as well as a migration corridor for others (Quintana et al., 2017). This region lies along the Andes of southern Ecuador and northern Peru approximately between 4°S–7°S and consists of relatively low-elevation mountains that create a mixture of environments (Fig. 7). The Huancabamba Depression seems to have influenced the radiation of several Andean lizard clades, such as Stenocercus Duméril and Bibron, 1837, Riama Gray, 1858, Macropholidus and Pholidobolus (Doan, 2003; Torres-Carvajal, 2007; Torres-Carvajal and Mafla-Endara, 2013), of which Macropholidus is the only radiation restricted to this region. It is thought that the Huancabamba area was at sea level by the Eocene, when other parts of the Andes were already uplifted, and it was not until the Middle Miocene that the Andes had emerged to form the Huancabamba Depression (Quintana et al., 2017). In a recent large scale phylogenetic and biogeographic analysis of the Cercosaurinae, the age of Macropholidus was estimated at 15.60 (12.36–18.90) mya, which roughly corresponds to the Middle Miocene (Torres-Carvajal et al., 2016). Thus, it is reasonable to think that the rise of the Andes along the Huancabamba Depression had a great impact on the evolution and diversification of Macropholidus lizards. This suggests that in addition to a biogeographic barrier and a migration corridor, the Huancabamba Depression has acted as a center of origin and diversification.
Omar Torres-Carvajal, Pablo J. Venegas and Pedro M. Sales Nunes. 2020. Description and Phylogeny of A New Species of Andean Lizard (Gymnophthalmidae: Cercosaurinae) from the Huancabamba Depression. South American J. of Herpetology. 18(1); 13-23. DOI: 10.2994/SAJH-D-18-00069.1
