Anolis osa Köhler, Dehling & Köhler, 2010, sp. nov.
Creators: name: Köhler, Gunther
name: Dehling, Matthias
name: Köhler, Johannes
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Dactyloidae
Anolis
Anolis osa

description: Anolis osa sp. nov.
Figs. 9–11
Anolis polylepis: Poe (2004, in part.).
Holotype. SMF 80645, an adult male from about 6.3 km WSW Rincón de Osa, 8°40’36.7’’N, 83°32’7.9’’W, about 150 m elevation, Puntarenas Province, Costa Rica, collected 22 February 2008 by Gunther Köhler and Johannes Köhler. Field tag number GK 2092.
Paratypes. SMF 89227–32, same collecting data as holotype. SMF 89215–21, UCR 20733–35, 2 km W Rincón de Osa, about 10 m elevation, Puntarenas Province, Costa Rica, collected 22 February 2008 by Gunther Köhler and Johannes Köhler. SMF 89260–61, 89427–29, Parque Nacional Corcovado, Estación Sirena, 8.48°N, 83.58°W, Puntarenas Province, Costa Rica, collected 10–11 August 2005 by Matthias Dehling. SMF 89227–29, SMF 89260–61, 89427–29, UCR 20733–35 are adult males with everted hemipenes. SMF 89230–32 are adult females.
Referred Specimen: See Appendix I.
Diagnosis. A medium-sized species (SVL in largest specimen 57 mm) of the genus Anolis (sensu Poe 2004) that differs from all other Lower Central American beta anoles (sensu Etheridge 1967) except Anolis apletophallus, A. cryptolimifrons, and A. limifrons in that it is long-legged (longest toe of adpressed hind leg reaches to at least center of eye), has smooth ventral scales, and a slender habitus, often delicate. Anolis osa differs from the species in the cluster listed above, except A. polylepis, by having two elongate, overlapping superciliaries (one such scale in A. apletophallus, A. cryptolimifrons, and A. limifrons), usually two anterior prenasal scales (versus one elongate prenasal scale) and dewlap coloration (usually orange with a darker orange basal portion in A. osa versus dirty white with a basal orange-yellow blotch in A. cryptolimifrons and A. limifrons, almost uniformly orange-yellow in A. apletophallus). Anolis osa differs from A. polylepis by having a unilobed hemipenis (bilobed in A. polylepis). Other anole species from Lower Central America that are somewhat similar in appearance to both A. osa and A. polylepis are A. tropidogaster and A. cupreus, the latter of which occurs syntopically at some localities with A. polylepis. However, both A. tropidogaster and A. cupreus have strongly keeled ventral scales (smooth in A. osa and A. polylepis). Also, the majority of males in A. tropidogaster have a pair of greatly enlarged postcloacal scales (these scales usually not enlarged in A. osa and A. polylepis). In the field, most individuals of A. osa and A. polylepis have a pale longitudinal lateral stripe (absent in Costa Rican populations of A. cupreus). For variation in selected morphometric and scalation characters of A. osa see Table 3.
Description of the holotype. Adult male as indicated by everted hemipenes and presence of large dewlap; SVL 50.5 mm; tail length 106 mm, tail complete; tail compressed in cross section, tail height 2.0 mm, tail width 1.4 mm; axilla to groin distance 20.8 mm; head length 13.3 mm, head length/SVL ratio 0.26; snout length 6.6 mm; head width 8.2 mm; longest toe of adpressed hind limb reaching to a point between eye and snout; shank length 14.6 mm, shank length/head length ratio 1.1; longest finger of extended forelimb reaching tip of snout; longest finger of adpressed forelimb reaches to anterior insertion of hind limbs. Scales on snout keeled (Fig. 10); 9 postrostrals; 10 scales between nasals; scales in distinct prefrontal depression slightly wrinkled; supraorbital semicircles well developed, separated by a minimum of 2 scales; supraorbital disc composed of 6 distinctly enlarged keeled scales; two elongated, strongly overlapping superciliaries, the anterior one much larger than the posterior scale; about 3–4 rows of small keeled scales extending between enlarged supraorbitals and superciliaries; interparietal scale well developed, 1.8 x 1.0 mm (length x width), surrounded by scales of moderate size; 2 scales present between interparietal and supraorbital semicircles; canthal ridge distinct, composed of 3 large (posterior two largest) and 6 small anterior canthal scales; 11 scales present between second canthals; 12 scales present between posterior canthals; 70 (right)–63 (left) mostly keeled loreal scales in a maximum of 8 (right)–9 (left) horizontal rows, with the scales of lower rows mostly keeled, and those of upper rows mostly tuberculated; subocular scales keeled, narrowly in contact with supralabials; 8 supralabials to level below center of eye; ear opening 0.7 x 1.4 mm (length x height); mental distinctly wider than long, almost completely divided medially, bordered posteriorly by 8 postmentals (outer larger than inner); 7 infralabials to level below center of eye; sublabials undifferentiated; slightly keeled granular scales present on chin and throat; dewlap extending well onto chest, anterior insertion at level of posterior canthals, posterior insertion about 6.0 mm beyond level of axilla; dorsum of body with keeled granular scales, 2 medial rows of slightly enlarged scales, largest dorsal scales about 0.28 x 0.22 mm (length x width); about 54 medial dorsal scales in one head length; about 85 medial dorsal scales between axilla and groin; lateral scales keeled, granular and homogeneous, average size 0.15 mm in diameter; ventrals at midbody smooth, bulging, subimbricate, about 0.23 x 0.23 mm (length x width); about 54 ventral scales in one head length; about 94 ventral scales between axilla and groin; about 176 scales around midbody; caudal scales strongly keeled; caudal middorsal scales slightly enlarged, without whorls of enlarged scales; precloacal scales pointed and granular; postcloacal scales not enlarged; no tube-like axillary pocket present; scales on dorsal surface of forelimb slightly keeled, imbricate, about 0.25 x 0.27 mm (length x width); digital pads dilated, dilated pad about 2 times width of non-dilated scales on distal phalanx; distal phalanx narrower than and raised from dilated pad; 25 (right)–25 (left) lamellae under phalanges II–IV of fourth toe; 9 scales under distal phalanx of fourth toe.
The completely everted hemipenis is a small unilobed organ; sulcus spermaticus bordered by well developed sulcal lips and opens at base of apex into a concave field without ornamentation; a small asulcate processus present; asulcal side of apex covered with fine calyces, truncus with transverse folds.
The extended dewlap in life has 6–7 horizontal gorgetal-sternal rows with 26–42 scales per row, rows somewhat irregular, some of them with pairs or triplets of scales, apical portion of dewlap between marginal pairs and last gorgetal-sternal row free of scales; modal number of anterior marginal pairs 4–5.
Coloration in life was recorded as follows: Dorsal ground color Dark Drab (119B) with a Pale Horn Color (92) broken longitudinal lateral stripe, edged diffusely by Mars Brown (223A) pigment; a Sepie (119) shoulder spot, edged posteriorly by a Yellow Ocher (123C) blotch; dorsum of head Dark Drab (119B) with a Hair Brown (119A) interorbital bar; dorsal surfaces of limbs Army Brown (219B) with indistinct Tawny Olive (223D) markings; tail Brick Red (132A) with indistinct Tawny Olive (223D) banding; tip of tail Tawny Olive (223D); ventral surfaces Glaucus (79); dewlap Orange Yellow (18), basal portion suffused with Raw Umber (23), gorgetals dirty white; iris Mars Brown (219A). Coloration after one year preservation in 70% ethanol agrees well with this description.
Variation. The paratypes agree well with the holotype in general appearance, morphometrics and scalation (see Table 1). We documented variation in relative hind leg length in this species. Of 66 specimens examined, the longest toe of the adpressed hind leg reached to mid-eye in 5 individuals (7.6%), to anterior margin of eye in 33 individuals (50.0%), and to a point between eye and snout in 28 individuals (42.4%). For variation in nasal region see Table 2 and Figure 1. For variation in dorsal pattern see Table 2 and Figure 2.
Etymology. The name osa is used as a noun in apposition and in reference to the Peninsula de Osa where the type series of the species was collected and where it is probably restricted.
A. polylepis A. osa
3 47 3 22
Ƥ 24 Ƥ 19
SVL 3 42.2–59.4 (51.3 ± 3.76) 49.9–55.4 (50.2 ± 2.28) Ƥ 39.6–53.5 (47.3 ± 3.52) 41.9–50.7 (46.4 ± 2.60) Tail length 3 80.1–117.0 (102.1 ± 10.28) 84.9–107.2 (97.3 ± 6.88) Ƥ 70.0–101.5 (86.3 ± 8.29) 73.1–93.0 (82.0 ± 4.59) HL 3 10.8–14.4 (12.8 ± 0.88) 11.3–13.9 (12.4 ± 0.62) Ƥ 10.1–13.7 (11.9 ± 0.78) 10.4–12.8 (11.5 ± 0.60) HW 3 6.7–8.5 (7.7 ± 0.48) 7.0–8.2 (7.5 ± 0.35) Ƥ 6.3–8.5 (7.3 ± 0.56) 6.7–7.9 (7.1 ± 0.36) Shank length 3 11.6–16.0 (13.9 ± 1.12) 12.2–15.0 (13.6 ± 0.66) Ƥ 10.5–14.0 (12.4 ± 0.98) 11.0–13.2 (12.3 ± 0.65) Axilla–groin distance 3 16.3–26.1 (21.2 ± 2.16) 18.5–24.4 (21.3 ± 1.32) Ƥ 15.5–24.1 (19.87 ± 2.14) 17.8–29.4 (20.7 ± 2.60) Natural history notes. Anolis osa is an extremely common anole that reaches high population densities. At most sites on the Peninsula de Osa it was the most abundant species of anole. During daytime, most individuals were observed perching head down on the lower parts (30–120 cm above the ground) of trunks of small trees and other plants such as heliconias (Heliconiaceae) and banana plants (Musaceae). Males of A. osa are very territorial and will show aggressive display behavior whenever another adult male is placed in reaching distance (less than about 150 cm). The species was studied in detail by Andrews (1971, 1983), and Savage (2002) summarized much of the information provided by her.
Geographic distribution. As currently known, Anolis osa is restricted to the Peninsula de Osa, Costa Rica. It occurs both in protected areas (Corcovado National Park) and in disturbed areas such as at the type locality. The documented vertical range of the species is from sea level to about 550 m elevation.
description: Published as part of Köhler, Gunther, Dehling, Matthias & Köhler, Johannes, 2010, Cryptic species and hybridization in the Anolis polylepis complex, with the description of a new species from the Osa Peninsula, Costa Rica (Squamata: Polychrotidae), pp. 23-38 in Zootaxa 2718 on pages 28-33, DOI: 10.5281/zenodo.199772