Panolopus chalcorhabdus ( Schwartz 1964 )

Schools, Molly & Hedges, Blair, 2024, A new forest lizard fauna from Caribbean islands (Squamata, Diploglossidae, Celestinae), Zootaxa 5554 (1), pp. 1-306 : 143-147

Panolopus chalcorhabdus ( Schwartz 1964)

Big-nosed Smooth-scaled Forest Lizard

(Fig. 54)

Diploglossus costatus chalcorhabdus Schwartz, 1964:37 . Holotype: MCZ R-77158, collected by Richard Thomas from 0.9 mi. SE El Macas , La Romana Province, Dominican Republic, on 31 August 1963 (18.4278, -68.9743; 31 m).

Celestus costatus chalcorhabdus — Schwartz & Henderson, 1988:94.

Celestus costatus chalcorhabdus — Schwartz & Henderson, 1991:368.

Celestus costatus chalcorhabdus — Hedges et al., 2019:16.

Celestus costatus chalcorhabdus — Schools & Hedges, 2021:231.

Material examined (n=8). DOMINICAN REPUBLIC. La Altagracia. KU 225001 , 0.9 mi SE El Macao , 31 August 1963 ; KU 225003 , 3.2 mi W Higuey , 28 August 1963 ; KU 225076–7 , mouth Rio Chavon , W side, 15 July 1972 ; KU 225078–9 , 3.3 mi SE El Macao , 20 July 1972 . La Romana. KU 225002 , 8 km E La Romana , 19 July 1963 ; MCZ R-77158, Richard Thomas , 0.9 mi. SE El Macas, 31 August 1963 .

Diagnosis. Panolopus chalcorhabdus has (1) a dorsal pattern of absent/irregular flecks/irregular dots, (2) head markings absent/present, (3) markings in the longitudinal paramedian area absent/present, (4) dots arranged in bars in the lateral band present, (5) an adult SVL of 71.9–95.4 mm, (6) ventral scale rows, 88–97, (7) midbody scale rows, 36–41, (8) total lamellae on one hand, 40–52, (9) total strigae on ten scales, 184–233, (10) relative length of all digits on one hindlimb, 31.3–36.0 %, (11) relative distance between the angled subocular and mouth, 0.481 –0.818 %, (12) relative eye length, 3.07–3.71 %, (13) relative forelimb length, 20.4–23.7 %, (14) relative ear width, 1.26–1.65 %, (15) relative rostral height, 1.85–2.24 %, (16) relative head length, 16.6–18.8 %, (17) relative mental width, 1.47–2.00 %, (18) relative postmental width, 2.38–3.31 %, (19) relative cloacal width, 7.74–9.08 %, (20) relative prefrontal width, 4.37–4.93 %, (21) relative largest supraocular width, 2.52–2.86 %, (22) relative longest finger length, 5.29–6.97 %, (23) relative distance between the ear and eye, 6.82–8.58 %, (24) relative head width, 65.0–76.3 %, (25) relative frontal width, 62.5–80.8 %, (26) relative nasal height, 0.854–1.55 %, (27) relative angled subocular height, 0.739 –0.854 %, (28) relative distance between the eye and naris, 4.93–5.62 %, (29) relative canthal iii length, 1.98–2.05 %, (30) relative angled subocular width, 2.36–2.71 %, and (31) relative nasal length, 1.70–2.01 %. No genetic data are available to estimate the species stem of crown time.

We distinguish Panolopus chalcorhabdus from the other species of Panolopus based on a complex of traits. From Panolopus aenetergum , we distinguish P. chalcorhabdus by the ventral scale rows (88–97 versus 80–86), the total strigae on ten scales (184–233 versus 267), the relative length of digits on one hindlimb (31.3–36.0 versus 26.8), the relative cloacal width (7.74–9.08 versus 7.60), the relative prefrontal width (4.37–4.93 versus 4.15), the relative largest supraocular width (2.52–2.86 versus 2.49), the relative longest finger length (5.29–6.97 versus 4.83), the relative head width (65.0–76.3 versus 76.4), the relative frontal width (62.5–80.8 versus 88.2), the relative angled subocular height (0.739 –0.854 versus 1.08), the relative distance between the eye and naris (4.93–5.62 versus 4.35), the relative width of canthal iii (1.98–2.05 versus 1.86), and the relative angled subocular width (2.36– 2.71 versus 2.07). From P. aporus , we distinguish P. chalcorhabdus by the relative width of canthal iii (1.98–2.05 versus 1.85–1.96). From P. costatus , we distinguish P. chalcorhabdus by the relative width of canthal iii (1.98–2.05 versus 1.82–1.90). From P. curtissi , we distinguish P. chalcorhabdus by the dots arranged in bars in the lateral areas (present versus absent), the total lamellae on one hand (40–52 versus 32–39), the relative length of digits on one hindlimb (31.3–36.0 versus 20.8–28.1), the relative longest finger length (5.29–6.97 versus 3.59–4.54), and the relative width of canthal iii (1.98–2.05 versus 1.75–1.93). From P. diastatus , we distinguish P. chalcorhabdus by the relative length of digits on one hindlimb (31.3–36.0 versus 21.5–27.4), the relative forelimb length (20.4– 23.7 versus 16.2–20.1), and the relative longest finger length (5.29–6.97 versus 3.48–4.87). From P. emys , we distinguish P. chalcorhabdus by the adult SVL (71.9–95.4 versus 99.0–113), the total strigae on ten scales (184–233 versus 238–311), the relative prefrontal width (4.37–4.93 versus 3.99–4.36), the relative angled subocular width (2.36–2.71 versus 2.12–2.20), and the relative nasal width (1.70–2.01 versus 1.23–1.58). From P. hylonomus , we distinguish P. chalcorhabdus by the dots arranged in bars in the lateral areas (present versus absent), the relative length of digits on one hindlimb (31.3–36.0 versus 22.8–28.2), and the relative longest finger length (5.29–6.97 versus 4.47–5.27). From P. lanceolatus sp. nov., we distinguish P. chalcorhabdus by the angled subocular width by the angled subocular height (2.77–3.28 versus 3.29–5.91) (see Remarks). From P. lapierrae sp. nov., we distinguish P. chalcorhabdus by the relative length of digits on one hindlimb (31.3–36.0 versus 24.3–30.9), the relative longest finger length (5.29–6.97 versus 4.49–4.55), the relative head width (65.0–76.3 versus 77.7–78.1), and the relative width of canthal iii (1.98–2.05 versus 1.54–1.86). From P. leionotus , we distinguish P. chalcorhabdus by the relative largest supraocular width (2.52–2.86 versus 1.94–2.50) and the relative width of canthal iii (1.98–2.05 versus 1.55– 1.89). From P. marcanoi , we distinguish P. chalcorhabdus by the angled subocular width by the angled subocular height (2.77–3.28 versus 3.37–5.36) (see Remarks). From P. melanchrous , we distinguish P. chalcorhabdus by the relative width of canthal iii (1.98–2.05 versus 1.67–1.94). From P. neiba , we distinguish P. chalcorhabdus by the relative width of canthal iii (1.98–2.05 versus 1.51–1.95). From P. nesobous , we distinguish P. chalcorhabdus by the relative rostral height (1.85–2.24 versus 2.26–2.38). From P. oreistes , we distinguish P. chalcorhabdus by the relative nasal width (1.70–2.01 versus 1.37–1.65). From P. psychonothes , we distinguish P. chalcorhabdus the angled subocular width by the angled subocular height (2.77–3.28 versus 2.37–2.72) (see Remarks). From P. saonae , we distinguish P. chalcorhabdus by the relative length of digits on one hindlimb (31.3–36.0 versus 26.5– 29.8), the relative forelimb length (20.4–23.7 versus 19.0–20.2), the relative prefrontal width (4.37–4.93 versus 4.14), the relative longest finger length (5.29–6.97 versus 5.01), the relative distance between the eye and naris (4.93–5.62 versus 6.43), and the relative angled subocular width (2.36–2.71 versus 2.31). From P. semitaeniatus sp. nov., we distinguish P. chalcorhabdus the relative ear width (1.26–1.65 versus 1.90–2.30), the relative rostral height (1.85–2.24 versus 2.41–2.63), the relative head width (65.0–76.3 versus 58.8–63.8), the relative angled subocular height (0.739 –0.854 versus 0.654), the relative distance between the eye and naris (4.93–5.62 versus 4.61), the relative width of canthal iii (1.98–2.05 versus 1.80), the relative nasal width (1.70–2.01 versus 1.51). From P. unicolor sp. nov., we distinguish P. chalcorhabdus by the adult SVL (71.9–95.4 versus 67.6), the total strigae on ten scales (184–233 versus 144), the relative length of digits on one hindlimb (31.3–36.0 versus 36.8), the relative cloacal width (7.74–9.08 versus 7.61), the relative largest supraocular width (2.52–2.86 versus 3.12), the relative frontal width (62.5–80.8 versus 58.2), the relative width of canthal iii (1.98–2.05 versus 1.79), and the relative angled subocular width (2.36–2.71 versus 2.90).

Description of holotype. MCZ R-77158. An adult male; SVL 95.1 mm; tail nearly cylindrical, 129 mm (136% SVL); axilla-to-groin distance 55.0 mm (57.8% SVL); forelimb length 22.6 mm (23.8% SVL); hindlimb length 30.5 mm (32.1% SVL); head length 17.5 mm (18.4% SVL); head width 13.2 mm (13.9% SVL); head width 75.4% head length; diameter of orbit 2.97 mm (3.12% SVL); horizontal diameter of ear opening 1.50 mm (1.58% SVL); vertical diameter of ear opening 1.30 mm (1.37% SVL); length of all toes on one foot 29.9 mm (31.4% SVL); shortest distance between angled subocular and lip 0.78 mm (0.820% SVL); shortest distance between the ocular and auricular openings 8.19 mm (8.61% SVL); longest finger length 5.07 mm (5.33% SVL); largest supraocular width 2.40 mm (2.52% SVL); cloacal width 8.66 mm (9.11% SVL); mental width 1.70 mm (1.79% SVL); prefrontal width 4.42 mm (4.65% SVL); frontal width 80.8% frontal length; nasal height 1.48 mm (1.56% SVL); angled subocular height 0.78 mm (0.820% SVL); shortest distance between the eye and naris 4.76 mm (5.01% SVL); canthal iii width 1.89 mm (1.99% SVL); angled subocular width 2.56 mm (2.69% SVL); nasal width 1.92 mm (2.02% SVL); rostral 2.23X 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 an almost straight posterior margin, much 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 much smaller than parietals and separating them, posteriorly touching the interoccipital, which is approximately as wide as 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 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)/(right), excluded from contact with supraocular by canthal iii (left)/(right); final loreal posteriorly bordering the upper and lower preoculars (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)/(right); 9 median oculars (left)/(right), 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)/8 (right) infralabials, 6 (left)/5 (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 1–4 scales; 88 transverse rows of dorsal scales from interoccipital to base of tail; 89 transverse rows of ventral scales from mental to vent; 40 scales around midbody; 5 digits; finger lengths 3>4>2>5>1; 11 (left)/12 (right) lamellae under longest finger; 45 total lamellae on one hand; toe lengths 4>3>5>2>1; 18 (left)/17 (right) lamellae under longest toe; dorsal body and caudal scales keelless and striate; faintly striated ventral scales; 238 total strigae counted on ten scales.

FIGURE 54. (A–F) Panolopus chalcorhabdus (MCZ R-77158, holotype), SVL 95.1 mm.

Color (in alcohol): dorsal surface of head golden tan; lateral surfaces of head grading from golden tan to cream with darker brown eye masks; dorsal surfaces of the body are red-gray with small, irregular, darker brown flecks; dorsal surface of tail red-gray with irregular, darker brown spots; lateral areas grade from dark brown to cream with darker brown and off-white dots in bars; dorsal surfaces of the limbs are golden tan with darker brown mottling; lateral and ventral areas of the limbs fade to pale cream, patternless; ventral surfaces of the head, body, and tail are pale cream color with some brown mottling under the chest and tail.

Variation. The examined material has dorsal patterns that range from completely absent to irregular flecks or dots. In KU 225002 the pattern vaguely resembles chevrons. All specimens have patternless heads except for KU 225001, which has a few dark, irregular markings on the head scales. The majority of specimens have a few flecks in the longitudinal paramedian series; however, KU 225078 has no markings and KU 225002 has small longitudinal paramedian lines. All specimens have dots arranged in bars in the lateral band. Measurements and other morphological data for the holotype and other examined material are presented in Table 1.

Distribution. Panolopus chalcorhabdus is distributed in the extreme east of the Dominican Republic at elevations of 0–110 m (Fig. 50).

Ecology and conservation. No ecological data are associated with this species. We consider the conservation status of Panolopus chalcorhabdus to be Least Concern, based on IUCN Redlist criteria ( IUCN 2023). It is likely a common species tolerant of some habitat disturbance, based on what is known of most species of Panolopus . However, it faces a primary threat of habitat destruction resulting from deforestation.A secondary threat is predation from introduced mammals, including the mongoose and black rats. Studies are needed to determine the health and extent of remaining populations and better understand the threats to the survival of the species.

Reproduction. No data on reproduction are available for this species.

Etymology. The species name is derived from the Greek chalcos (copper or bronze) and rhabdos (line or stripe) in reference to the distinctive dorsal pattern of this species.

Remarks. Originally a subspecies of Panolopus costatus , we elevate this taxon to species level. Panolopus chalcorhabdus and P. lanceolatus sp. nov. cannot be morphologically separated based on our standard suite of characters, however, they can be separated by the angled subocular width divided by the angled subocular height (2.77–3.28 [n=5] versus 3.29–5.91 [n=7]). Panolopus chalcorhabdus and P. marcanoi cannot be morphologically separated based on our standard suite of characters, however, they can be separated by the angled subocular width divided by the angled subocular height (2.77–3.28 [n=5] versus 3.37–5.36 [n=18]). Panolopus chalcorhabdus and P. psychonothes cannot be morphologically separated based on our standard suite of characters, however, they can be separated by the angled subocular width divided by the angled subocular height (2.77–3.28 [n=5] versus 2.37–2.72 [n=5]).

Additional museum specimens identified as P. costatus from the region should be examined to determine if they are members of P. chalcorhabdus . Panolopus chalcorhabdus was not included in our genetic dataset and future studies using genetic or genomic data should be made to determine the relationships of P. chalcorhabdus .