Research Article |
Corresponding author: Robert C. Jadin ( rcjadin@gmail.com ) Academic editor: Alexander Haas
© 2021 Robert C. Jadin, Michael J. Jowers, Sarah A. Orlofske, William E. Duellman, Christopher Blair, John C. Murphy.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jadin RC, Jowers MJ, Orlofske SA, Duellman WE, Blair C, Murphy JC (2021) A new vine snake (Reptilia, Colubridae, Oxybelis) from Peru and redescription of O. acuminatus. Evolutionary Systematics 5(1): 1-12. https://doi.org/10.3897/evolsyst.5.60626
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The Brown Vine Snake, Oxybelis aeneus, was until recently considered a single species, distributed from southern Arizona through the Neotropics into southeastern Brazil. However, newly conducted research restructured the species with a substantial taxonomic revision, recognizing five additional taxa (i.e. O. koehleri, O. microphthalmus, O. potosiensis, O. rutherfordi, O. vittatus) in this species complex. This revision focused on populations in North America, Central America, and northern South America while neglecting the southern portion of its distribution. Here, we examine the taxonomic history of the complex and use it along with specimen data to resurrect O. acuminatus from southeastern Brazil. Finally, we describe a new species from the Peruvian Amazon based on morphological characters. This work increases the species diversity of the O. aeneus complex to eight, and we expect further increases in biodiversity discoveries with continued exploration of the New World vine snakes.
Amazon, conservation, Inkaterra, morphology, new species, Serpentes, Squamata, South America, systematics, taxonomy
Widespread Neotropical snakes with distributions extending from North America to South America, occupy a variety of habitats and often contain unrecognized species diversity. Species such as the Boa constrictor (
The Brown Vine Snake, Dryinus aeneus Wagler, 1824, was described from a specimen collected at Ega, Brazil, (now Tefé, Brazil) on the south bank of the Amazon River at its junction with the Rio Tefé (Holotype ZSM 2645/0). Wagler was unaware that the generic name was preoccupied by Dryinus
A, Illustration of Coluber acuminatus reproduced from
A, Illustration of Dryophis vittatus
Recently,
Alcohol-preserved specimens of Oxybelis aeneus sensu lato from throughout its range were examined at the Field Museum of Natural History and the University of Wisconsin – Stevens Point Museum of Natural History (Appendix
To determine the distinctiveness of our Peruvian specimens and O. acuminatus within the Oxybelis aeneus complex we conducted a principal component analysis (PCA). We lumped our examined specimens into groups representing these two groups and the distinct species identified in
Our morphological analyses suggest distinctiveness among members of the Oxybelis aeneus complex, including O. acuminatus and specimens from Peru (Table
Plot of PC-1 and PC-2 scores extracted from a Principle Components Analysis of twelve morphological characters, showing distinct clustering among geographically defined groups. Circular symbols represent Oxybelis acuminatus (red), O. aeneus (orange), O. koehleri (yellow), O. microphthalmus (light blue), O. potosiensis (green), O. rutherfordi (dark blue), O. vittatus (brown), and Peruvian specimens (gray).
A morphological comparison of the eight species in the Oxybelis aeneus complex.
Oxybelis acuminatus | O. aeneus | O. inkaterra sp. nov. | O. koehleri | O. microphthalmus | O. potosiensis | O. rutherfordi | O. vittatus | |
---|---|---|---|---|---|---|---|---|
Upper labials in orbit | 3 (4-5-6) | 3 (4-5-6) | 3 (4-5-6) | 3 (4-5-6) | 3 (4-5-6) | 2 (4-5) or (5-6) | 2 (4-5) | 3 (4-5-6) |
Stripes on venter | Indistinct | No | No | Variable | Variable | Variable | Yes | Yes |
Preocular shorter than eye diameter | Yes | Yes | Yes | Yes | no | Yes | Yes | Yes |
Posterior border of internasals extends beyond posterior edge of first upper labial | Yes | Yes | No | Yes | Yes | Yes | No | No |
Chin heavily mottled | No | No | Yes | Yes, in females | No | No | No | No |
Supraocular longer than prefrontal | Yes | No, equal in length | No, equal in length | No, equal in length | Yes | Yes | Yes | Yes |
Second upper labial contacts preocular | Yes | No | No | No | No | No | No | No |
Second pair of chin shields contacting each other | No | No | No | Yes | Yes | Yes | Yes | Yes |
Number of lower labials contacting first pair of chin shields | 5 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
Oxybelis aeneus – Keiser, 1974:7;
KU 220196 (Figs
Holotype of Oxybelis inkaterra sp. nov., KU 220196 in life from Reserva Amazonica, formerly Cusco Amazonico, Peru (W.E. Duellman).
Holotype of Oxybelis inkaterra sp. nov., KU 220196 preserved. A, Dorsal whole specimen; B, ventral whole specimen views; C, top of the head; D, profile. Scale bar: 1 cm.
Paratypes. KU 214887, Peru, Madre de Dios: Cusco Amazónico, Río Madre de Dios, c. 15 km E Puerto Maldonado, 200 m, 12°34'59.88"S, 69°4'59.879"W; collected by Erik R. Wild (Field number WED 59004), 23 December 1989; ZMH R01702, Peru, Huánuco: Pachitea, Panguana Biological Fieldstation, Rio Yuyapichis [= Rio Llullapichis], 260 m, approx. 9°41'S, 74°57'W, collected by János Regös July 1980.
FMNH 56141, from Peru, Loreto, Río Ucayali: Yarinacocha (c. 13°51'S, 71°1'W), collected by J.M. Schunke, 05 Sep 1946. FMNH 40085 (female), from the Madre de Dios area of Peru (no specific locality). ZMH R01611, Peru, Huánuco: Pachitea, Panguana Biological Fieldstation, Rio Yuyapichis [= Rio Llullapichis], 260 m, approx. 9°35'S, 74°56'W, collected by Carlos Vasquez Modena 1980.
Like other members of the Oxybelis aeneus complex O. inkaterra has an elongated head and body, 8–9 upper labials, four lower labials contacting the first pair of chin shields, 173–205 ventrals and 158–203 subcaudals; a divided anal plate, dorsal scales in 17–17–13 rows, and undivided hemipenes.
A vine snake with (1) three upper labials (4–5–6) bordering the orbit; (2) numerous bold black bars and spots present on the body; (3) ventral surface mottled with dense black spots; (4) preocular shorter than eye diameter; (5) second pair of chin shields separated by smaller scales posteriorly; (6) nine upper labials, three located behind the orbit; (7) snout from above relatively broad, tapered, and flat rostrum; (8) supraocular and prefrontal are about the same length; (9) last upper labial about same length as primary temporal; (10) much of the lower surface of the head infused with black pigment; (11) second upper labial not in contact with preocular.
Oxybelis inkaterra can be distinguished from the seven other members of the Oxybelis aeneus complex by the presence of, upper labials three and four are in contact the preocular; a head with an irregular, darkly pigmented ventral surface with pale spots; and eyespot markings on the posterior ventral surface of the body and tail; the snout of O. inkaterra is also relatively short and broad compared to other species in the Oxybelis aeneus complex (Fig.
A comparison between the snout shapes of Oxybelis aeneus (FMNH 64417) (top) and O. inkaterra (FMNH 56141) (bottom) (JCM).
A male with everted hemipenes (Fig.
Top of the head is brown with dark brown to black mottling (Figs
(Fig.
Whereas surrounding the black spots was not as pronounced in smaller individuals, KU 220196 has the first 33 ventral scales almost completely black (in preservative), but the stripes are still visible (Fig.
This species occurs in the Amazonian rainforest of Peru in the departments of Huánuco, Loreto, and Madre de Dios. It is likely the species also occurs in Ucayali between these departments and possibly adjacent Bolivia, Brazil, and Colombia.
At Reserva Amazónica, Oxybelis inkaterra is found in the dense vegetation on the bank of the Río Madre de Dios and in an adjacent clearing. The steep riverbank has vegetation unlike that of the adjacent rainforest. There are shrubby plants and no canopy; adjacent to the river are stands of the cane-like Gynerium saggitatum (Ponaceae). Oxybelis inkaterra is a diurnal arboreal snake, which, if like other members of the genus, has a fondness for small lizards. In the scrub forest adjacent to the river two species, Gonatodes humeralis (Sphaerodactylidae) and Anolis fuscoauratus (Dactyloidae), inhabit the scrub and probably are primary prey of the vine snake.
KU 220196, weight 30.5 g, caught on the ground in camp during the day. Dorsum and venter grayish tan with dark brown flecks and streaks. Top of head brown; lateral stripe on head dark brown, bordered below by white. Iris cream with horizontal dark brown stripe. Lining of mouth and throat black. KU 214887, caught in bush 1.5 m above ground by day edge of river in camp. Mass 15 g, 895 mm TL.
The specific epithet honors the ecotourism company Inkaterra (https://www.inkaterra.com/) and its non-profit NGO counterpart Inkaterra Asociación. These two institutions started in 1975 and 1978, respectively, were founded by José E. Koechlin von Stein to promote education and conservation of Peruvian culture and ecosystems. Inkaterra and Mr. Koechlin have been recognized numerous times with awards and accolades for providing sustainable ecotourism and research opportunities for scientists. The type locality, Cusco Amazónico (now Reserva Amazónica), is owned and operated by Inkaterra and is the site of one of the most thoroughly studied areas in the Neotropics, particularly for amphibian and reptile natural history (e.g. Duellman, 2005;
Anti-predator adaptations in snakes are numerous and diurnal species can be expected to use visual coloration and behaviors to deter predators (Green, 1997). Eyespots are circular markings, often with concentric rings and conspicuous colors, that occur in many animals. They have been hypothesized to work as a way to startle or intimidate predators or they may work by being highly salient stimuli that promote sensory overload, biases, or neophobic reactions (
Coluber acuminatus
– Wied, in Anonymous, 1824: 667. Holotype AMNH 3886. The type locality Rio Espirito Santo, in southeastern Brazil (~19°2'S, 40°43'W). Note that the name Coluber acuminatus was published in June of 1824, and it was long given priority over Wagler’s Dryinus aeneus 1824, which was published in March of 1824, see
Oxybelis aeneus aeneus
– Bogert & Oliver, 1945: 391.
A vine snake with (1) three upper labials (4–5–6) bordering the orbit on the left; (2) black bars or spots present on the anterior body; (3) indistinct stripe on the outer edges of ventral scales, venter finely mottled; (4) eye diameter greater than preocular length; (5) second pair of chin shields separated by smaller scales for most of their length; (6) nine upper labials, three located behind the orbit; (7) snout from above relatively broad, slightly tapered, and flat at rostrum; (8) supraocular longer than prefrontals; (9) last upper labial longer than primary temporal; (10) lower surface of head uniform in color; (11) second upper labial in contact with preocular (this character state appears to occurs only in this taxa).
Oxybelis acuminatus can be distinguished from all other members in the O. aeneus complex by having their second upper labial contacting their preocular (Fig.
This species is likely restricted to the Atlantic Forest of southeastern Brazil.
Although our PCA analysis did not distinguish O. acuminatus or O. inkaterra from all other species of the O. aeneus complex, this not surprising given the large number of species in the analysis and the depauperate morphologically distinguishing characters available due to the cryptic nature of this species complex. Furthermore, the analysis placed these two species near Middle American taxa not likely to be the most closely related species based on geography. Therefore, we consider this analysis valuable in distinguishing them from other South American taxa and utilize additional morphological features to clearly distinguish all taxa from each other (see taxonomic descriptions above and Table
Molecular techniques combined with morphological analyses are increasing the number of recognized squamate species.
Peru is a biodiversity hotspot (
The presence of an endemic Oxybelis in Peru is noteworthy and may help elucidate how diverse ecological factors may drive regional patterns of species divergence and speciation (
Approximately 12% of snakes are estimated to be threatened with extinction (
We thank T. Dowling and C. Johnson (ASU); A. Resetar (FMNH); L.J. Welton and R.M. Brown (KU); G.A. Rivas (MBLUZ); J. Rosado, T. Takahashi, and J. Hanken (MCZ); G. Bradley and P. Rienthal (UAZ); C.M. Sheehy III, D.C. Blackburn, M.A. Nickerson (UF); G. Schneider (UMMZ); C.J. Franklin, G. Pandelis, E.N. Smith, and J.A. Campbell (UTA); and M.G. Rutherford (UWIMZ) for allowing us to examine specimens under their care. We thank D.A. Kiziran and L. Vonnahme (AMNH) for photographs of the type specimen of Coluber acuminatus and S. Lotzkat for an in-life photograph of O. vittatus. We thank J. Hallermann (ZMH) for providing us data on specimens under his care. This manuscript was improved by reviews from J. Hallermann and E. Lehr. RCJ, SAO, and WED greatly appreciate the kind generosity of José E. Koechlin von Stein and the staff at Inkaterra for their friendship and support of our research over the years. MJJ was supported by the Portuguese Foundation for Science and Technology (FCT, SFRH/BPD/109148/2015).
Specimens examined
Museum acronyms follow
Oxybelis aeneus – (n = 8) Brazil: FMNH 64417 Amazonas; FMNH 19203 Pará; KU R-124605, 124606, 140173, MCZ R-2582, 2778, and 53211 Pará.
O. brevirostris – (n = 2) Ecuador: UTA R-55952-53 Canton San Lorenzo: Parroquia Santa Rita, Esmeraldas.
O. inkaterra – (n = 6) Peru: FMNH 40085, Madre de Dios; FMNH 56141, Loreto, Rio Ucayali: Yarinacocha; KU R-214887 & R-220196 Madre de Dios, Cuzco Amazonico, 15 km E Puerto Maldanado; ZMH R01702 & R01611, Huánuco, Panguana Biological Station, Rio Yuyapichis [= Rio Llullapichis], Pachitea.
O. koehleri – (n = 34) Costa Rica: FMNH 179061 Cartago, Turrialba; El Salvador: FMNH 10997 Chalatenango; San Jose del Sacare, 3600′; FMNH 10998 Morazán, Divisadero; FMNH 64955, La Libertad, Volcan San Salvador, 1917 Lava, 500 m; FMNH 64956 La Paz, Los Blancos; KU 289907 Usulutan: Isla San Sebastian; Guatemala: FMNH 20088 Izabal: Bobos Plantation, near Playitas; FMNH 20171 and 20418 Sololá: Olas de Moca; UTA R-46795 Chiguimula; UTA R-45880 Huehuetenango; UTA R-22182–83, 33,040, 33,042, 37,256, 39,236, 42,433 Izabal; UTA R-37258 Peten; UTA R-46846 Zacapa, El Arenal; Honduras: FMNH 22231 Tela; FMNH 27050 San Pedro Sula; FMNH 34565, 34571, 34574, 34576, Bay Islands: Roatan, near Coxen Hole; UTA R-55231 Bay Islands: Roatan; FMNH 34770 Yoro, Portillo Grande; FMNH 40872 Gracias; UTA R-46865 Comayagua, Playitos: Aldea “Lo de Reina,” 785 m; UTA R-53176–78 Honduras: Gracias a Dios, Mocorón, 30–50 m. Nicaragua: UTA R-44838 Jinotega, El Paraíso Km 152.5, carretera Jinotega-Matagalpa, 1490 m.
O. microphthalmus – (n = 36) USA: Arizona: UAZ 47314 2.8 mi west of Sycamore Canyon; UAZ 519,225 miles east Sycamore Canyon, Ruby Rd.; UAZ 39544 Patagonia Mts.; Santa Cruz County: ASU 33314, ASU 33364, ASU 35069, ASU 35563, UAZ 16787, UAZ 39545; no specific locality: UMMZ 75779. Mexico: Colima: UTA R-57658; Guerrero UAZ 106056, 106058, 38448, 38451, 38455, 38461, 38467, 106051, 106057, 106059, 106054; Oaxaca: UAZ 106055, 117841–43, 178707, 178708; Sonora: UAZ 26972 0.5 miles West Alamos; UAZ 28279 8.8 miles east Alamos; Alamos UAZ 16797, UAZ 26973, ASU 06735, ASU 68990, ASU 88990; 35 miles east of Cannansa junction w/ Aqua Prieta Rd. UAZ 16796.
O. potosiensis – (n = 6) Mexico: UIMNH 25069 San Luis Potosí; UTA R-6107–10, 8752, and 12,368 S of Zapotitl, Puebla; UTA R-9014 6.0 mi E San Rafael, road to Rancho Nuevo, Tamaulipas.
O. rutherfordi – (n = 20) Tobago: FMNH 251213 Bloody Bay Rd., between Roxborough and Bloody Bay; Trinidad: FMNH 49973 no specific locality; FMNH 49974–75 Brickfield; FMNH 49976 Mount Harris, FMNH 49977–85 San Rafael; FMNH 215838 circa 3 miles S Simla-Quarry Rd., on Arima-Blanchisseuse Rd., egg farm; FMNH 215839 circa 2 miles S Simla-Quarry Rd., on Arima-Blanchisseuse Rd.; UTA R-64851 Arima Valley, William Beebe Tropical Research Centre, c. 6 km N Arima, 247 m; Venezuela: FMNH 17839–40 Puerto Viejo, Península de Paria, Sucre; MBLUZ 1268 between San Francisco de Macanao and Cerro Los Cedros, Isla de Margarita, Nueva Esparta.
O. vittatus – (n = 16) Panama: FMNH 152067 Almirante; FMNH 83552, 130674, 131314 Canal Zone: Summit; FMNH 161478 Canal Zone: Barro Colorado Island; FMNH 153665 Coiba Island; FMNH 170132 San Blas Territory: Soskantupu, 8°57'N, 77°44'W, 1 m; FMNH 154043 Bocas del Toro, 11 km NW Almirante 600 ft.; FMNH 154478, 154517 no locality data; MCZ R-22274, 22231, and 25118 Canal Zone; UF 65037, 65038, and 170469 Canal Zone.