Comptus maculatus ( Garman 1888 )

Schools, Molly & Hedges, Blair, 2024, A new forest lizard fauna from Caribbean islands (Squamata, Diploglossidae, Celestinae), Zootaxa 5554 (1), pp. 1-306 : 118-121

Comptus maculatus ( Garman 1888)

Lesser Cayman Forest Lizard

(Fig. 41–42)

Diploglossus maculatus Garman, 1888:105 . Holotype: MCZ R-6231, collected by Charles J. Maynard on Cayman Brac, on 16 May 1845 (19.7, -79.8).

Celestus maculatus — Barbour, 1930:100.

Celestus maculatus — Barbour, 1935:123.

Celestus maculatus — Barbour, 1937:139.

Celestus maculatus —Grant, 1941:41.

Celestus crusculus maculatus — Cousens, 1956:2.

Celestus crusculus maculatus — Schwartz & Henderson, 1991:370.

Celestus maculatus — Hedges et al., 2019.

Comptus maculatus — Schools & Hedges, 2021:226.

Comptus maculatus — Landestoy et al., 2022: 205.

Material examined (n=9). CAYMAN BRAC. ANSP 38507 , S. Blair Hedges and Carla Hass, 0.7 km E Hawkesbill Bay on A7 (~ 10km E West End), 1.7 km E Ashton Reid Drive, 14 April 2003 ; ANSP 38508–11 , S. Blair Hedges and Carla Hass, West End, Tiara Beach Hotel and surrounding area, 15 April 2003 ; ANSP 38512 , S. Blair Hedges and Carla Hass , 1.2 km E of West End, 15 April 2003 ; MCZ R-6231, Charles J. Maynard , 16 May 1845 ; SBH 266554 , S. Blair Hedges and Carla Hass, West End, Tiara Beach Hotel and surrounding area, 15 April 2003 , USNM 107973 , 31 March–25 April 1938 .

Diagnosis. Comptus maculatus has (1) a dorsal pattern of absent/chevrons, (2) head markings absent/present, (3) markings in the longitudinal paramedian area absent/present, (4) dots arranged in bars in the lateral band absent/ present, (5) an adult SVL of 60.1–81.3 mm, (6) ventral scale rows, 94–108, (7) midbody scale rows, 37–41, (8) total lamellae on one hand, 32–37, (9) total strigae on ten scales, 149–201, (10) relative length of all digits on one hindlimb, 24.8–27.0 %, (11) relative distance between the angled subocular and mouth, 0.556 –0.849 %, (12) relative eye length, 3.51–3.91 %, (13) relative forelimb length, 19.3–21.6 %, (14) relative ear width, 0.993–1.70 %, (15) relative rostral height, 1.67–1.88 %, (16) relative head length, 16.6–18.3 %, (17) relative mental width, 1.69–1.85 %, (18) relative postmental width, 2.32–2.86 %, (19) relative cloacal width, 8.29–9.23 %, (20) relative prefrontal width, 3.95–4.73 %, (21) relative largest supraocular width, 2.23–2.74 %, (22) relative longest finger length, 4.14–5.01 %, (23) relative distance between the ear and eye, 6.93–7.60 %, (24) relative head width, 69.6– 80.0 %, (25) relative frontal width, 66.6–81.9 %, (26) relative nasal height, 0.873–1.11 %, (27) relative angled subocular height, 0.815–1.05 %, (28) relative distance between the eye and naris, 4.81–5.20 %, (29) relative canthal iii length, 1.73–1.85 %, (30) relative angled subocular width, 2.25–2.52 %, and (31) relative nasal length, 1.50–1.77 %. The species stem time is 2.43 Ma and the species crown time is 0.01 Ma (Fig. 4).

Comptus maculatus differs in having a dorsal pattern of absent/chevrons from all other species of the genus and in having a smaller total lamellae count on one hand (32–37) than all other species of the genus.

From Comptus alloeides , we distinguish C. maculatus by the dorsal pattern (absent/chevrons versus irregular dots/dots in series/dots in chevrons), the adult SVL (60.1–81.3 versus 124–161), the total lamellae on one hand (32– 37 versus 43–58), the total strigae on ten scales (149–201 versus 237–323), and the relative longest finger length (4.14–5.01 versus 5.32–5.95). From C. arboreus sp. nov., we distinguish C. maculatus by the dorsal pattern (absent/ chevrons versus dots in series/dots in chevrons), the adult SVL (60.1–81.3 versus 93.2–123), the total lamellae on one hand (32–37 versus 48–54), the relative length of digits on one hindlimb (24.8–27.0 versus 37.4–39.7), the relative forelimb length (19.3–21.6 versus 24.1–25.3), the relative postmental width (2.32–2.86 versus 2.95–3.01), the relative longest finger length (4.14–5.01 versus 6.01–6.37), the relative width of canthal iii (1.73–1.85 versus 1.86–1.94), and the relative angled subocular width (2.25–2.52 versus 2.82–3.28). From C. badius , we distinguish C. maculatus by the dorsal pattern (absent/chevrons versus irregular dots/mottled), the total lamellae on one hand (32–37 versus 40–45), the total strigae on ten scales (149–201 versus 203–241), the relative mental width (1.69–1.85 versus 1.38), and the relative head width (69.6–80.0 versus 62.8–69.3). From C. stenurus , we distinguish C. maculatus by the dorsal pattern (absent/chevrons versus dots in series/dots in chevrons), the adult SVL (60.1–81.3 versus 121– 146), the total lamellae on one hand (32–37 versus 47–57), the relative length of digits on one hindlimb (24.8–27.0 versus 29.2–37.1), the relative forelimb length (19.3–21.6 versus 22.3–27.5), and the relative longest finger length (4.14–5.01 versus 5.89–7.19). From C. weinlandi , we distinguish C. maculatus by the dorsal pattern (absent/chevrons versus irregular dots/dots in series/dots in chevrons), the adult SVL (60.1–81.3 versus 101–133), the total lamellae on one hand (32–37 versus 43–55), and the relative longest finger length (4.14–5.01 versus 5.08–6.31).

Description of holotype. MCZ R-6231. An adult; SVL 54.0 mm; tail nearly cylindrical, broken in life near tip, regenerated, 62.7 mm (116% SVL); axilla-to-groin distance 34.1 mm (63.1% SVL); forelimb length 10.7 mm (19.8% SVL); hindlimb length 16.1 mm (29.8% SVL); head length 8.74 mm (16.2% SVL); head width 6.64 mm (12.3% SVL); head width 76.0% head length; diameter of orbit 2.11 mm (3.91% SVL); horizontal diameter of ear opening 0.41 mm (0.759% SVL); vertical diameter of ear opening 0.47 mm (0.870% SVL); length of all toes on one foot 13.9 mm (25.7% SVL); shortest distance between angled subocular and lip 0.30 mm (0.556% SVL); shortest distance between the ocular and auricular openings 3.80 mm (7.04% SVL); longest finger length 2.83 mm (5.24% SVL); largest supraocular width 1.31 mm (2.43% SVL); cloacal width 4.35 mm (8.06% SVL); prefrontal width 2.47 mm (4.57% SVL); frontal width 81.7% frontal length; nasal height 0.68 mm (1.26% SVL); angled subocular height 0.67 mm (1.24% SVL); shortest distance between the eye and naris 2.39 mm (4.43% SVL); canthal iii width 0.91 mm (1.69% SVL); angled subocular width 1.77 mm (3.28% SVL); nasal width 0.92 mm (1.70% SVL); rostral 1.91X as wide as high, barely 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 slightly concave posterior margin, much wider than long, bordered by posterior internasals, 1 st loreals, 1 st 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 smaller than parietals and separating them, posteriorly touching the interoccipital, which is wider than long; nasal single; nostril just posterior to suture between 1 st and 2 nd supralabials (left)/(right); 1 postnasal (left)/(right); 2 loreals (left)/(right); 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, wider than high (right), excluded from contact with supraocular by canthal iii (left)/(right); final loreal posteriorly bordering the lower preocular (left)/upper and lower preoculars (right); canthal iii wider than high (left)/(right), contacting 1 st median ocular, anterior supraciliary, upper and lower preocular, and 1 st and 2 nd loreals (left)/(right); 9 median oculars (left)/(right), 1 st contacting the prefrontal (left)/(right); 1 upper preocular (left)/(right); an irregular anterior supraciliary (left)/(right); 6 lateral oculars (left)/(right); 4 (left)/5 (right) temporals; 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); 8 infralabials (left)/(right), 5 to level below center of eye (left)/(right); mental small, followed by a single, small postmental; 4 pairs of enlarged chin shields; 1 st pair in contact with one another; 2 nd –4 th pairs separated by 1–3 scales; 99 transverse rows of dorsal scales from interoccipital to base of tail; 97 transverse rows of ventral scales from mental to vent; 38 scales around midbody; 5 digits; finger lengths 3>4>2>5>1; 9 lamellae under longest finger (left)/(right); 35 total lamellae on one hand; toe lengths 4>3>5>2>1; 13 (14 th divided) (left)/14 (15 th divided) (right) lamellae under longest toe; dorsal body and caudal scales striate with a faint median keel; smooth to faintly striated ventral scales; 122 total strigae counted on ten scales.

Color (in alcohol): dorsal surface of head pale tan, patternless; lateral surfaces of head grading from pale tan to pale cream with some medium brown mottling on the supralabials and darker brown eye masks; dorsal surfaces of the body are pale tan, patternless; dorsal surface of tail same as body; lateral areas fade from pale medium brown to yellow-cream; dorsal surfaces of the limbs are medium brown; lateral and ventral areas of the limbs fade to yellow-cream; ventral surfaces of the head, body, and tail are yellow-cream, patternless.

Variation. All of the material examined display a dorsal pattern of faded chevrons that is more prominent than that of the holotype. ANSP 38510 is the only specimen that displays any markings in the longitudinal paramedian area. Most specimens examined are patternless, however, ANSP 38511 and ANSP 38508 both show darker outlines on the head scale borders. Dots are arranged in bars in the lateral band most clearly in ANSP 38512, whereas SBH 266554 and ANSP 38507 display this pattern anteriorly. Measurements and other morphological data for the holotype and other examined material are presented in Table 1.

FIGURE 41. (A–E) Comptus maculatus (MCZ R-6231, holotype), SVL 54.0 mm.

Distribution. Comptus maculatus is distributed on Cayman Brac and Little Cayman Island, where it has been collected at elevations of 0–20 m (Fig. 35).

Ecology and conservation. Little is known of the ecology of this species other than that the holotype was taken from under a pile of coconut husks ( Garman 1888). On March 15–16, 2003, SBH found this species at three locations on Cayman Brac, among coconut husks under palm trees, after searching a much larger number of similarly ideal locations. Considerable search effort for this species was made throughout the length of Little Cayman without success .

The IUCN Redlist ( IUCN 2023) considers the conservation status of Comptus maculatus to be Endangered B1ab(iii)+2ab(iii) “due to its limited distribution (with an extent of occurrence of 163 km 2), known occurrence in at most five locations that are subject to ongoing threats from development (current and planned). However, because this species is secretive, research is needed to better clarify the current distribution, population status, and life history.” Studies are needed to determine the health of remaining populations and threats to the survival of the species. Captive-breeding programs should be undertaken, if possible.

Reproduction. On Cayman Brac, one female (58 mm SVL) was captured with two large yolked follicles in January ( Seidel & Franz 1994); litter size three (SBH, field data).

Etymology. The species name is a Latin singular masculine adjective meaning spotted, in reference to the lizard’s spotted pattern.

Remarks. The type description speculated that this species was closely related to Celestus crusculus and Celestus occiduus . Cousens (1956) felt that the morphological differences between Comptus maculatus and Celestus crusculus were insufficient, so she designated Comptus maculatus as a subspecies of Celestus crusculus ( Celestus crusculus maculatus ), keeping it as a subspecies because of a different colored tail. Comptus maculatus was referred to as a full species in later works (Hedges 2008; Henderson & Powell 2009; Hedges et al. 2019; Hedges 2024).

Interestingly, Comptus maculatus was likely treated as a subspecies of Celestus crusculus because of the smaller distance between Jamaica and the Cayman Islands, in comparison to that between Hispaniola and the Cayman Islands. Initial genetic data showing that it was closer to Comptus stenurus , reported later by Dennison (2010), an honors student working in the laboratory of SBH, led SBH to raise it to full species status in Caribherp (Hedges 2008). The phylogeny built by Schools & Hedges (2021) with expanded genetic data had a topology that placed C. maculatus within the genus Comptus , the remainder of which is found on Hispaniola. Schools et al. (2022) confirmed this placement with genomic data and indicated that an overwater dispersal event between Hispaniola and the Cayman Islands led to the current distribution of Comptus maculatus .

Comptus maculatus 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. alloeides and C. weinlandi . Based on our timetree (Fig. 4), C. maculatus diverged from its closest relative 2.43 Ma, consistent with typical species of vertebrates (> 0.7 Ma; Hedges et al. 2015). Comptus maculatus was recognized as a distinct species by our ASAP analysis.

FIGURE 42. Comptus maculatus (ANSP 38511), in life. From West End, Cayman Brac, Cayman Islands. Photo by SBH.