Comptus stenurus ( Cope 1862a )

Schools, Molly & Hedges, Blair, 2024, A new forest lizard fauna from Caribbean islands (Squamata, Diploglossidae, Celestinae), Zootaxa 5554 (1), pp. 1-306 : 122-125

Comptus stenurus ( Cope 1862a)

Macaya Keeled Forest Lizard

(Fig. 43–44)

Diploglossus stenurus Cope, 1862:188 . Holotype: MCZ R-3612, collected by David Friedrich Weinland from “near Jeremie,” Grand’Anse department, Haiti. Date of collection inferred to be 1857–1858 ( Weinland 1858). (18.64, -74.11).

Celestus stenurus — Cope, 1879:272.

Diploglossus stenurus stenurus — Schwartz, 1964:8.

Celestus stenurus — Schwartz & Henderson, 1988:100.

Celestus stenurus — Schwartz & Henderson, 1991:378.

Comptus stenurus — Schools & Hedges, 2021:226.

Comptus stenurus — Landestoy et al. 2022 2022:205.

Material examined (n=14). HAITI. Sud. ANSP 38544–5 , Richard Thomas and Manuel Leal, 8.6 km SW of Carretour Joute on the Presquille de Port Salut, near Riviere la Source , 6 June 1991 ; ANSP 38546 , S. Blair Hedges, Caye Madeline , 3 October 2010 ; ANSP 38550 , S. Blair Hedges and Richard Thomas, Port Salut, Gumbwa, near Ça Vilason , 24 July 2010 ; BMNH 1964.309 – 10 , Camp Perrin ; KU 227167 , 4.5 mi N Camp Perrin , 27 June 1979 ; MCZ R-133108–9, George Whiteman, St Croix, 7–8 mi NE Paillant , 1–31 July 1972 ; SBH 269020 , S. Blair Hedges and Richard Thomas, Port Salut, Gumbwa, near Ça Vilason , 24 July 2010 ; SBH 267494 , Eladio Fernandez, Île-à-Vache .

Grand’Anse. MCZ R-3612, David Friedrich Weinland, Jeremie, 1857–8 ; MCZ R-119419–20, Thomas Preston Webster III, Alan Ross Kiester, and Haitians , Castillon , 31 August 1969 .

Diagnosis. Comptus stenurus has (1) a dorsal pattern of dots in series/dots in chevrons, (2) head markings absent/present, (3) markings in the longitudinal paramedian area present, (4) dots arranged in bars in the lateral band absent/present, (5) an adult SVL of 121–146 mm, (6) ventral scale rows, 87–110, (7) midbody scale rows, 38–45, (8) total lamellae on one hand, 47–57, (9) total strigae on ten scales, 176–234, (10) relative length of all digits on one hindlimb, 29.2–37.1 %, (11) relative distance between the angled subocular and mouth, 0.676–1.12 %, (12) relative eye length, 2.99–3.92 %, (13) relative forelimb length, 22.3–27.5 %, (14) relative ear width, 0.451–1.87 %, (15) relative rostral height, 1.68–2.03 %, (16) relative head length, 15.8–18.9 %, (17) relative mental width, 1.52–1.78 %, (18) relative postmental width, 2.61–3.05 %, (19) relative cloacal width, 8.73–10.3 %, (20) relative prefrontal width, 4.32–4.71 %, (21) relative largest supraocular width, 2.53–3.11 %, (22) relative longest finger length, 5.89– 7.19 %, (23) relative distance between the ear and eye, 6.18–7.42 %, (24) relative head width, 70.2–74.2 %, (25) relative frontal width, 68.0–79.2 %, (26) relative nasal height, 0.992–1.17 %, (27) relative angled subocular height, 0.697 –0.893 %, (28) relative distance between the eye and naris, 4.38–5.53 %, (29) relative canthal iii length, 1.37–1.97 %, (30) relative angled subocular width, 2.31–2.85 %, and (31) relative nasal length, 1.39–1.82 %. The species stem time is 2.38 Ma and the species crown time is 0.08 Ma (Fig. 4).

We distinguish Comptus stenurus from the other species of Comptus based on a complex of traits. From Comptus alloeides , we distinguish C. stenurus by the total strigae on ten scales (176–234 versus 237–323). From C. arboreus sp. nov., we distinguish C. stenurus by the relative length of digits on one hindlimb (29.2–37.1 versus 37.4–39.7) and the relative angled subocular height (0.697 –0.893 versus 0.929 –0.992). From C. badius , we distinguish C. stenurus by the dorsal pattern (dots in series/dots in chevrons versus irregular dots/mottled), the adult SVL (121– 146 versus 78.2–99.1), the total lamellae on one hand (47–57 versus 40–45), the relative mental width (1.52–1.78 versus 1.38), the relative postmental width (2.61–3.05 versus 2.39), the relative longest finger length (5.89–7.19 versus 4.38–5.04), and the relative head width (70.2–74.2 versus 62.8–69.3). From C. maculatus , we distinguish C. stenurus by the dorsal pattern (dots in series/dots in chevrons versus absent/chevrons), the adult SVL (121–146 versus 60.1–81.3), the total lamellae on one hand (47–57 versus 32–37), the relative length of digits on one hindlimb (29.2–37.1 versus 24.8–27.0), the relative forelimb length (22.3–27.5 versus 19.3–21.6), and the relative longest finger length (5.89–7.19 versus 4.14–5.01). From C. weinlandi , we cannot distinguish C. stenurus based on our standard suite of characters (see Remarks).

Description of holotype. MCZ R-3612. An adult male; SVL 146 mm; tail nearly cylindrical, broken at tip, regenerated, 241 mm (165% SVL); axilla-to-groin distance 79.6 mm (54.5% SVL); forelimb length 40.2 mm (27.5% SVL); hindlimb length 52.0 mm (35.6% SVL); head length 25.9 mm (17.7% SVL); head width 18.3 mm (12.5% SVL); head width 70.7% head length; diameter of orbit 5.55 mm (3.80% SVL); horizontal diameter of ear opening 2.04 mm (1.40% SVL); vertical diameter of ear opening 1.76 mm (1.21% SVL); length of all toes on one foot 56.4 mm (38.6% SVL); shortest distance between angled subocular and lip 1.42 mm (0.973% SVL); shortest distance between the ocular and auricular openings 10.8 mm (7.40% SVL); longest finger length 10.5 mm (7.19% SVL); largest supraocular width 3.70 mm (2.53% SVL); cloacal width 15.0 mm (10.3% SVL); mental width 2.60 mm (1.78% SVL); postmental width 4.46 mm (3.05% SVL); prefrontal width 6.48 mm (4.44% SVL); frontal width 79.2% frontal length; nasal height 1.59 mm (1.09% SVL); angled subocular height 1.19 mm (0.815% SVL); shortest distance between the eye and naris 7.29 mm (4.99% SVL); canthal iii width 2.00 mm (1.37% SVL); angled subocular width 4.16 mm (2.85% SVL); nasal width 2.66 mm (1.82% SVL); rostral 2.03X as wide as high, visible from above, not in contact with nasals, in contact with 1 st supralabial and anterior internasal (left)/(right); anterior internasals are narrower than posterior ones; frontonasals and prefrontal fused into a single large plate with a concave posterior margin, wider than long, bordered by posterior internasals, 1 st loreals, 1 st and 2 nd median oculars, and the frontal; frontal longer than wide; a pair of frontoparietals, separated by the posterior prolongation of the frontal and the interparietal plate; interparietal plate slightly smaller than parietals and separating them, posteriorly touching the interoccipital, which is wider than long; parietal separated from supraoculars by 1 st and 2 nd temporals and frontoparietal (left)/(right); nasal single; nostril above suture between 1 st and 2 nd supralabials (left)/(right); 1 postnasal (left)/(right); 2 (left)/3 (right) loreals; 1 st loreal higher than wide (left)/(right), in contact with postnasal, posterior internasal, prefrontal/frontonasal complex, 1 st median ocular, canthal iii, 2 nd loreal, and 3 rd –4 th supralabials (left)/(right); 2 nd loreal shorter than 1 st, approximately as high as wide (left)/shorter than 1 st, irregular (right), excluded from contact with supraocular by canthal iii (left)/(right); 3 rd loreal shorter than 1 st, approximately as high as wide, excluded from contact with supraocular by canthal iii (right); final loreal posteriorly bordering the lower and upper preocular (left)/(right); canthal iii wider than high (left)/(right), contacting 1 st median ocular, anterior supraciliary, upper preocular, and 1 st and 2 nd loreals (left)/1 st median ocular, anterior supraciliary, upper preocular, and 1 st –3 rd loreals (right); 10 (left)/(right) median oculars, 1 st and 2 nd contacting the prefrontal (left)/(right); 1 upper preocular (left)/(right); an irregular anterior supraciliary (left)/(right); 6 lateral oculars (left)/(right); 5 temporals (left)/(right); 2 suboculars (left)/(right); posterior subocular large and elongate (left)/(right); anterior subocular small (left)/(right); 9 supralabials (left)/(right), 6 to level below center of eye (left)/(right); 9 (left)/10 (right) infralabials, 5 (left)/6 (right) to level below center of eye; mental small, followed by a single, larger postmental; 4 pairs of enlarged chin shields; 1 st pair in contact with one another anteriorly, posteriorly separated by one scale; 2 nd –4 th pairs separated by 1–5 scales; 97 transverse rows of dorsal scales from interoccipital to base of tail; 98 transverse rows of ventral scales from mental to vent; 42 scales around midbody; 5 digits; finger lengths 3>4>2>5>1; 13 lamellae under longest finger (left)/(right); 52 total lamellae on one hand; toe lengths 4>3>5>2>1; 19 (left)/20 (right) lamellae under longest toe; dorsal body and caudal scales striate with a median keel; ventral scales lightly striated; 210 total strigae counted on ten scales.

Color (in alcohol): dorsal surface of head golden tan, patternless; lateral surfaces of head grading from golden tan to cream; dorsal surfaces of the body are golden tan with some darker brown scales, most scales are missing; dorsal surfaces of tail are golden tan with some darker brown scales, most scales are missing; almost all scales missing on the lateral areas; dorsal surfaces of the limbs are golden tan with darker spots; lateral and ventral areas of the limbs fade to cream, patternless; ventral surfaces of the head, body, and tail are pale cream, patternless.

Variation. The other specimens examined have more scales intact than the holotype. All specimens show large dots that are continuations of the longitudinal paramedian series whereas the large dots in ANSP 38550 appear in multiple series and the large dots in KU 227167 appear as almost stripes across the back. The longitudinal paramedian lines appear as either complete lines or large dots in series. Dots arranged in bars in the lateral band are split almost evenly as being present and absent. Measurements and other morphological data for the holotype and other examined material are presented in Table 1.

Distribution. Comptus stenurus is distributed in the western portion of the Tiburon peninsula of Haiti, including Île-à-Vache and the Macaya mountains, but not at the tip of the peninsula (region of Tiburon), at elevations of 0–1070 m (Fig. 35).

Ecology and conservation. Past literature accounts of ecological data for this species conflate multiple species and therefore cannot be used. SBH found individuals under rocks and logs in areas recently cleared of forest. Six males 110–123 mm SVL weighed 18.5–31 g, whereas two females, 140 and 143 mm SVL, weighed 44 and 58 g ( SBH field data from Grand’Anse, Haiti, between Marche Leon and Castillon). This species appears to be tolerant of some habitat disturbance and can be abundant in places .

FIGURE 43. (A–F) Comptus stenurus (MCZ R-3612, holotype), SVL 146 mm.

FIGURE 44. Comptus stenurus (SBH 269019), in life. From Gumbwa, Port Salut, Sud Department, Haiti. Photo by SBH.

We consider the conservation status of Comptus stenurus sp. nov. to be Least Concern, primarily because it has been encountered frequently in the past, based on IUCN Redlist criteria ( IUCN 2023). However, clearing of forests for agriculture in Haiti is a severe environmental pressure on biodiversity ( Hedges et al. 2018). Also, introduced predators, including the mongoose and black rats, likely prey upon this species. Therefore, studies are needed to determine the health and extent of the populations, and threats to the survival of the species.

Reproduction. Past literature accounts of ecological data for this species conflate multiple species and therefore cannot be used.

Etymology. The species name stenurus is derived from the Greek words stenos meaning “narrow” and oura meaning “tail,” referring to the tail of the species.

Remarks. Cochran (1941) synonymized Comptus stenurus with Panolopus costatus , along with numerous other species; however, this taxonomic action was not retained in later works ( Schwartz 1970). When Caribicus warreni was described, Schwartz (1970) speculated that its closest relative was Comptus stenurus because of the presence of median keels on the dorsal and caudal scales, a suggestion not supported by our molecular phylogeny, which places them in different generic clades. Previously, both Comptus stenurus rugosus and C. weinlandi were regarded as subspecies of C. stenurus . However, we synonymize C. stenurus rugosus with C. weinlandi (see accounts below).

Comptus stenurus and C. weinlandi cannot be distinguished based on our suite of morphological characters; however, both of these species are morphologically distinct from their closest relatives ( C. arboreus and C. alloeides , respectively). Additionally, C. stenurus and C. weinlandi are genetically distinct (Fig. 3) and diverged 4.22 Ma (Fig. 4). Future studies should examine additional characters to morphologically distinguish C. stenurus from C. weinlandi .

Comptus stenurus is included in our genetic dataset and has significant support in both Bayesian and ML likelihood analyses at the crown node of the species and the stem node that places it as the closest relative to C. arboreus sp. nov. Based on our timetree (Fig. 4), C. stenurus diverged from its closest relative 2.38 Ma, consistent with typical species of vertebrates (> 0.7 Ma; Hedges et al. 2015). Comptus stenurus was recognized as a distinct species by our ASAP analysis.