Panolopus aporus ( Schwartz 1964 )

Schools, Molly & Hedges, Blair, 2024, A new forest lizard fauna from Caribbean islands (Squamata, Diploglossidae, Celestinae), Zootaxa 5554 (1), pp. 1-306 : 139-143

Panolopus aporus ( Schwartz 1964)

Barahona Smooth-scaled Forest Lizard

(Fig. 52–53)

Diploglossus curtissi aporus Schwartz, 1964:45 . Holotype: MCZ R-77159, collected by David C. Leber and Richard Thomas from 13.1 mi SW Enriquillo , Pedernales Prov., Dominican Republic, on 30 July 1963 (17.7939, -71.3753; 8 m).

Diploglossus curtissi aporus — Greer, 1967:96.

Diploglossus curtissi aporus — Ober, 1970:275.

Celestus curtissi aporus — Schwartz & Henderson, 1988:98.

Celestus curtissi aporus — Schwartz & Henderson, 1991:371.

Celestus curtissi aporus — Hedges et al., 2019.

Panolopus curtissi aporus — Schools & Hedges, 2022:230.

Material examined (n=41). DOMINICAN REPUBLIC. Barahona. KU 79827 , 5 km NE Enriquillo , 7 August 1963 ; KU 226024 , 226027–8 , 0.5 mi NE Caleton , 8 December 1971 ; USNM 328742 , Richard Thomas and S. Blair Hedges, ca. 4–5 km S Barahona, 2.7 km W of, via coast road and road to Filipinas , 20 August 1984 ; USNM 328743 , S. Blair Hedges and Richard Thomas, ca. 4.5 km S, 4.0 km W of Barahona, via coast road and road to Filipinas , 20 August 1984 ; USNM 328744 , S. Blair Hedges, 15 km SSW of La Guazara , 21 June 1985 ; USNM 328793 , S. Blair Hedges and Richard Thomas, 11.3 km S of Barahona , 20 August 1984 . Pedernales. Hispaniola . AMNH 92798 , D. C. Leber, 5 mi NE Oviedo , 30 July 1963 ; ANSP 38623–7 , S. Blair Hedges, Richard Thomas, and locals, Bucan Detwi , 6 January 1998 ; ANSP 38628–9 , S. Blair Hedges, Matthew Heinicke, N. Coro, Pedernales town , in palm grove, 20 August 2005 ; KU 226021–3 , 13.1 mi SW Enriquillo , 30 July 1963 ; KU 226041–2 , 13.1 mi SW Enriquillo ; MCZ R-77159, David C. Leber and Richard Thomas, 13.1 mi SW Enriquillo , 30 July 1963 ; USNM 328766–8 , S. Blair Hedges and Richard Thomas, Juancho , 17 August 1984 ; USNM 328769–72 , Richard Thomas and S. Blair Hedges, Los Arroyos , 27 August 1984 ; USNM 328794–800 , S. Blair Hedges and Richard Thomas, 6.4 km SW, 0.7 km SE (road) of Juancho , 16 August 1984 . HAITI. Sud-Est. ANSP 38630–1 , S. Blair Hedges, Tiffany Cloud, Miguel Landestoy, Marcos Rodriguez, Southeast of Pic La Selle , 20 November 2011 ; SBH 269908 , 269910–1 , S. Blair Hedges, Tiffany Cloud, Miguel Landestoy, Marcos Rodriguez, Southeast of Pic La Selle , 20 November 2011 .

Diagnosis. Panolopus aporus has (1) a dorsal pattern of absent/irregular flecks/irregular dots/dots in chevrons, (2) head markings absent, (3) markings in the longitudinal paramedian area absent/present, (4) dots arranged in bars in the lateral band present, (5) an adult SVL of 77.8–100 mm, (6) ventral scale rows, 85–102, (7) midbody scale rows, 37–42, (8) total lamellae on one hand, 36–48, (9) total strigae on ten scales, 150–235, (10) relative length of all digits on one hindlimb, 27.7–33.7 %, (11) relative distance between the angled subocular and mouth, 0.441 – 0.669 %, (12) relative eye length, 2.91–3.76 %, (13) relative forelimb length, 19.3–26.4 %, (14) relative ear width, 1.06–1.88 %, (15) relative rostral height, 2.01–2.40 %, (16) relative head length, 10.2–18.6 %, (17) relative mental width, 1.72–2.08 %, (18) relative postmental width, 2.42–2.92 %, (19) relative cloacal width, 7.92–8.86 %, (20) relative prefrontal width, 4.18–4.53 %, (21) relative largest supraocular width, 2.74–3.62 %, (22) relative longest finger length, 4.57–5.72 %, (23) relative distance between the ear and eye, 6.73–8.49 %, (24) relative head width, 71.4–83.2 %, (25) relative frontal width, 61.7–75.1 %, (26) relative nasal height, 1.08–1.23 %, (27) relative angled subocular height, 0.638–1.02 %, (28) relative distance between the eye and naris, 4.69–5.44 %, (29) relative canthal iii length, 1.85–1.96 %, (30) relative angled subocular width, 2.32–2.73 %, and (31) relative nasal length, 1.56–1.78 %. The species stem time is 2.04 Ma and the species crown time is 0.27 Ma (Fig. 4).

We distinguish Panolopus aporus from the other species of Panolopus based on a complex of traits. From Panolopus aenetergum , we distinguish P. aporus by the midbody scale rows (37–42 versus 35–36), the total strigae on ten scales (150–235 versus 267), the relative length of digits on one hindlimb (27.7–33.7 versus 26.8), the relative distance between angled subocular and mouth (0.441 –0.669 versus 0.717), the relative mental width (1.72– 2.08 versus 1.63), the relative cloacal width (7.92–8.86 versus 7.60), the relative prefrontal width (4.18–4.53 versus 4.15), the relative largest supraocular width (2.74–3.62 versus 2.49), the relative frontal width (61.7–75.1 versus 88.2), the relative angled subocular height (0.638–1.02 versus 1.08), the relative distance between the eye and naris (4.69–5.44 versus 4.35), the relative angled subocular width (2.32–2.73 versus 2.07), and the relative nasal width (1.56–1.78 versus 1.92). From P. chalcorhabdus , we distinguish P. aporus by the relative width of canthal iii (1.85–1.96 versus 1.98–2.05). From P. costatus , we distinguish P. aporus by the total lamellae on one hand (36–48 versus 49–58). From P. curtissi , we distinguish P. aporus by the dots arranged in bars in the lateral areas (present versus absent) and the relative longest finger length (4.57–5.72 versus 3.59–4.54). From P. diastatus , we distinguish P. aporus by the relative length of digits on one hindlimb (27.7–33.7 versus 21.5–27.4) and the relative largest supraocular width (2.74–3.62 versus 1.88–2.57). From P. emys , we distinguish P. aporus by the total strigae on ten scales (150–235 versus 238–311) and the relative angled subocular width (2.32–2.73 versus 2.12–2.20). From P. hylonomus , we distinguish P. aporus by the dots arranged in bars in the lateral areas (present versus absent) and the adult SVL (77.8–100 versus 59.3–76.5). From P. lanceolatus sp. nov., we distinguish P. aporus by the relative largest supraocular width (2.74–3.62 versus 2.20–2.71) and the relative nasal height (1.08–1.23 versus 0.904–1.06). From P. lapierrae sp. nov., we distinguish P. aporus the relative prefrontal width (4.18–4.53 versus 4.73–4.75), the relative longest finger length (4.57–5.72 versus 4.49–4.55), the relative frontal width (61.7–75.1 versus 77.6–79.0), and the relative nasal width (1.56–1.78 versus 1.81). From P. leionotus , we distinguish P. aporus by the relative largest supraocular width (2.74–3.62 versus 1.94–2.50). From P. marcanoi , we distinguish P. aporus by the head markings (absent versus present). From P. melanchrous , we distinguish P. aporus by the relative longest finger length (4.57–5.72 versus 5.76–7.09) and the relative nasal height (1.08–1.23 versus 0.897 –0.952). From P. neiba , we distinguish P. aporus by the relative distance between angled subocular and mouth (0.441 –0.669 versus 0.670 –0.747). From P. nesobous , we distinguish P. aporus by the total lamellae on one hand (36–48 versus 50–59), the relative length of digits on one hindlimb (27.7–33.7 versus 35.1), the relative prefrontal width (4.18–4.53 versus 4.74–4.81), the relative longest finger length (4.57–5.72 versus 6.19–6.33), the relative distance between the eye and naris (4.69–5.44 versus 5.62–5.73), and the relative width of canthal iii (1.85–1.96 versus 2.01–2.12). From P. oreistes , we distinguish P. aporus by the relative nasal height (1.08–1.23 versus 0.878–1.06). From P. psychonothes , we distinguish P. aporus by the relative largest supraocular width (2.74–3.62 versus 1.92–2.68). From P. saonae , we distinguish P. aporus by the relative mental width (1.72–2.08 versus 1.52), the relative prefrontal width (4.18–4.53 versus 4.14), the relative nasal height (1.08–1.23 versus 1.01), the relative distance between the eye and naris (4.69– 5.44 versus 6.43), the relative width of canthal iii (1.85–1.96 versus 1.99), and the relative angled subocular width (2.32–2.73 versus 2.31). From P. semitaeniatus sp. nov., we distinguish P. aporus by the relative ear width (1.06– 1.88 versus 1.90–2.30), the relative rostral height (2.01–2.40 versus 2.41–2.63), the relative head width (71.4–83.2 versus 58.8–63.8), the relative distance between the eye and naris (4.69–5.44 versus 4.61), the relative width of canthal iii (1.85–1.96 versus 1.80), and the relative nasal width (1.56–1.78 versus 1.51). From P. unicolor sp. nov., we distinguish P. aporus by the adult SVL (77.8–100 versus 67.6), the total strigae on ten scales (150–235 versus 144), the relative length of digits on one hindlimb (27.7–33.7 versus 36.8), the relative cloacal width (7.92–8.86 versus 7.61), the relative prefrontal width (4.18–4.53 versus 4.69), the relative longest finger length (4.57–5.72 versus 6.65), the relative head width (71.4–83.2 versus 70.8), the relative frontal width (61.7–75.1 versus 58.2), the relative distance between the eye and naris (4.69–5.44 versus 5.52), the relative width of canthal iii (1.85–1.96 versus 1.79), the relative angled subocular width (2.32–2.73 versus 2.90), and the relative nasal width (1.56–1.78 versus 2.00).

FIGURE 52. (A–F) Panolopus aporus (MCZ R-77159, holotype), SVL 78.4 mm.

Description of holotype. MCZ R-77159. An adult female; SVL 78.4 mm; tail nearly cylindrical, broken, 28.7 mm (36.6% SVL); axilla-to-groin distance 46.9 mm (59.8% SVL); forelimb length 15.1 mm (19.3% SVL); hindlimb length 23.7 mm (30.2% SVL); head length 13.1 mm (16.7% SVL); head width 9.35 mm (11.9% SVL); head width 71.4% head length; diameter of orbit 2.44 mm (3.11% SVL); horizontal diameter of ear opening 0.83 mm (1.06% SVL); vertical diameter of ear opening 0.68 mm (0.867% SVL); length of all toes on one foot 21.7 mm (27.7% SVL); shortest distance between angled subocular and lip 0.48 mm (0.612% SVL); shortest distance between the ocular and auricular openings 5.85 mm (7.46% SVL); longest finger length 3.69 mm (4.71% SVL); largest supraocular width 2.15 mm (2.74% SVL); cloacal width 6.67 mm (8.51% SVL); mental width 1.63 mm (2.08% SVL); postmental width 1.90 mm (2.42% SVL); prefrontal width 3.28 mm (4.18% SVL); frontal width 61.7% frontal length; nasal height 0.92 mm (1.17% SVL); angled subocular height 0.80 mm (1.02% SVL); shortest distance between the eye and naris 3.68 mm (4.69% SVL); canthal iii width 1.54 mm (1.96% SVL); angled subocular width 1.82 mm (2.32% SVL); nasal width 1.22 mm (1.56% SVL); rostral 2.32 X 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 slightly concave posterior margin, much wider than long, bordered by posterior internasals, 1 st loreals, canthal iii, 1 st and 2 nd median oculars, and the frontal; frontal longer than wide; a pair of frontoparietals (fused with frontal on the left), 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 temporals 1–2 and frontoparietal (left)/(right); 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, 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 lower preocular (left)/(right); canthal iii wider than high (left)/(right), contacting 1 st median ocular, anterior supraciliary, the upper and lower preoculars, prefrontal/frontonasal complex, and 1 st and 2 nd loreals (left)/(right); 10 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); 5 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 (left)/10 (right) supralabials, 6 (left)/7 (right) to level below center of eye; 9 (left)/10 (right) infralabials, 6 to level below center of eye (left)/(right); 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 1–3 scales; 91 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; 11 (left)/12 (right) lamellae under longest finger; 44 total lamellae on one hand; toe lengths 4>3>5>2>1; 17 (left)/18 (right) lamellae under longest toe; dorsal body and caudal scales keelless and striate; smooth ventral scales; 189 total strigae counted on ten scales.

Color (in alcohol): dorsal surface of head gray-tan, patternless; lateral surfaces of head grading from pale tan to cream with darker brown eye masks and other darker brown areas on the supralabial scales; dorsal surfaces of the body are red-gray with faint longitudinal paramedian lines that end before the forearms; dorsal surface of tail red-gray; lateral areas grading from dark red-brown to cream with darker brown and off-white dots arranged 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 with some brown mottling under the throat.

Variation. Dorsal pattern in this species ranges from completely absent to irregular flecks or dots to dots arranged in chevrons. The dorsal color ranges from medium brown to gray-brown. In all specimens the head scales are patternless. Markings in the longitudinal paramedian series range from completely absent (ANSP 38629) to dots in series to broken or complete longitudinal paramedian lines. Dots in the lateral band are arranged in bars in all specimens. Measurements and other morphological data for the holotype and other examined material are presented in Table 1.

Distribution. Panolopus aporus is distributed primarily on the Barahona Peninsula of the Dominican Republic at coastal and near-coastal locations (0–1928 m). It also is found in the Massif de la Selle, southeast of Pic La Selle.

Ecology and conservation. Specimens of this species were commonly collected during the day from under logs, rocks, leaf litter, and rotting coconut husks and fronds.

We consider the conservation status of Panolopus aporus 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 agriculture and charcoaling. 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.

FIGURE 53. Panolopus aporus (USNM 328744, SBH 160291), SVL 97.8 mm, in life. From 15 km SSW of La Guazara, Barahona Province, Dominican Republic. Photo by SBH.

Reproduction. Litter sizes of 3–6 have been recorded in this species (SBH, field data).

Etymology. According to Schwartz (1964), the name ( aporus ) is derived from the Greek word for “puzzled,” in reference to the lack of understanding of the affinities of the taxon.

Remarks. Previously considered a subspecies of Panolopus curtissi , herein we elevate P. aporus to species level based on morphological and genetic distinction. Museum collections commonly include this species; however, additional sampling to determine the current state of present-day populations would benefit future assessments.

Panolopus aporus is included in our genetic dataset and has significant support in both Bayesian and ML likelihood analyses at the crown node that defines it as a species. The stem node placing P. aporus as the closest relative to P. curtissi had a support value of 58% in our ML analysis and was not supported in our Bayesian analysis. Schools et al. (2022) used genomic data to place P. aporus as the closest relative to P. curtissi with a significant support value in the ML analysis and a support value of 80% in the Bayesian analysis. Based on our timetree (Fig. 4), P. aporus diverged from its closest relative 2.04 Ma, consistent with typical species of vertebrates (> 0.7 Ma; Hedges et al. 2015). Panolopus aporus was recovered as conspecific with Panolopus oreistes in our ASAP analysis.