Panolopus costatus Cope, 1862b

Schools, Molly & Hedges, Blair, 2024, A new forest lizard fauna from Caribbean islands (Squamata, Diploglossidae, Celestinae), Zootaxa 5554 (1), pp. 1-306 : 147-152

Panolopus costatus Cope, 1862b

Tiburon Smooth-scaled Forest Lizard

(Fig. 55–56)

Panolopus costatus Cope 1862:494 . Holotype: MCZ R-3606, collected by Dr. 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 phoxinus — Cope, 1868:125. Holotype: R-12457, collected by Dr. David Friedrich Weinland from “near Jeremie,”

Grand’Anse department, Haiti. Date of collection inferred to be 1857–1858 ( Weinland 1858). (18.64, -74.11). Diploglossus phoxinus — Boulenger, 1885:289. Panolopus costatus — Boulenger, 1885:295. Diploglossus ohlendorffi —Fischer, 1886:3. Holotype: HZM, destroyed in WWII. Diploglossus nuchalis —Boulenger, 1898:920. Holotype: BMNH 1897.3.16.1, from Dr. F. Werner of unknown origin. Celestus costatus — Barbour, 1930:99. Celestus costatus — Barbour, 1935:123. Celestus costatus — Barbour, 1937:139. Celestus costatus —Mertens, 1939:70. Celestus costatus — Cochran, 1941:243. Diploglossus costatus costatus — Schwartz, 1964:21.

Celestus costatus — Schwartz & Henderson, 1991:368.

Celestus costatus — Powell et al., 1999:104.

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

Panolopus costatus — Schools & Hedges, 2021:230.

Panolopus costatus — Landestoy et al., 2022: 205.

Material examined (n=24). HAITI. Grand’Anse. ANSP 38558 , S. Blair Hedges, Richard Thomas, Manuel Leal, and Nicholas Plummer, Abricots (outskirts), 31 May 1991 ; ANSP 38559 , S. Blair Hedges, 17.0 km S of Beaumont , 1 June 1991 ; KU 225088 , 7 mi W Jeremie , 19 June 1971 ; KU 225089 , 225091 , btw La Foret and Jeremie , 16 March 1966 ; KU 225116–7 , ca 3 km (airline) SW Corail , 20 March 1966 ; KU 225171 , 225173 , Castillon to ca 2 km S Castillon, 26 June 1971 ; MCZ R-3606, David Friedrich Weinland, Jeremie , 1857–1858 ; SBH 269064 , 6.2 km E Anse d’Hainault at source cacao ; USNM 328773 , locals, vic. of Castillon (8.0 km S, 0.3 km E Marche Leon [airline]), 2 November 1984 ; USNM 328775–9 , locals, Castillion , 2 November 1984 ; USNM 328780 , S. Blair Hedges and Richard Thomas, 3 km SW of Castillion , 31 October 1984 . Nippes. MCZ R-134262–4, George Whiteman, 7–8 mi NE Paillant , 1–31 July 1972 . Sud. ANSP 38560 , S. Blair Hedges, 11.6 km NW Les Anglais, on Morne Grand Bois , 26 July 2011 ; ANSP 38561 , S. Blair Hedges and Richard Thomas, ca. 1 km NE of Tiburon , 21 July 2010 ; SBH 268974 , S. Blair Hedges and Richard Thomas, ca. 1 km NE Tiburon.

Diagnosis. Panolopus costatus has (1) a dorsal pattern of absent/irregular dots/dots in series/dots in chevrons, (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 83.6–107 mm, (6) ventral scale rows, 89–106, (7) midbody scale rows, 39–43, (8) total lamellae on one hand, 49–58, (9) total strigae on ten scales, 158–217, (10) relative length of all digits on one hindlimb, 31.5–37.8 %, (11) relative distance between the angled subocular and mouth, 0.582 –0.916 %, (12) relative eye length, 2.52–3.73 %, (13) relative forelimb length, 19.9–24.2 %, (14) relative ear width, 0.590–2.07 %, (15) relative rostral height, 1.78–2.26 %, (16) relative head length, 16.3–20.0 %, (17) relative mental width, 1.66–2.00 %, (18) relative postmental width, 2.29–2.92 %, (19) relative cloacal width, 7.27–8.51 %, (20) relative prefrontal width, 3.97–4.67 %, (21) relative largest supraocular width, 1.93–3.01 %, (22) relative longest finger length, 5.53–6.66 %, (23) relative distance between the ear and eye, 7.32–8.89 %, (24) relative head width, 68.3–76.8 %, (25) relative frontal width, 56.2–67.4 %, (26) relative nasal height, 1.02–1.28 %, (27) relative angled subocular height, 0.562 –0.886 %, (28) relative distance between the eye and naris, 5.08–5.50 %, (29) relative canthal iii length, 1.82–1.90 %, (30) relative angled subocular width, 2.36–2.81 %, and (31) relative nasal length, 1.58–1.74 %. The species stem time is 2.43 Ma and the species crown time is 0.73 Ma (Fig. 4) .

We distinguish Panolopus costatus from the other species of Panolopus based on a complex of traits. From Panolopus aenetergum , we distinguish P. costatus by the ventral scale rows (89–106 versus 80–86), the midbody scale rows (39–43 versus 35–36), the total lamellae on one hand (49–58 versus 40), the total strigae on ten scales (158–217 versus 267), the relative length of digits on one hindlimb (31.5–37.8 versus 26.8), the relative mental width (1.66–2.00 versus 1.63), the relative longest finger length (5.53–6.66 versus 4.83), the relative frontal width (56.2– 67.4 versus 88.2), the relative angled subocular height (0.562 –0.886 versus 1.08), the relative distance between the eye and naris (5.08–5.50 versus 4.35), the relative angled subocular width (2.36–2.81 versus 2.07), and the relative nasal width (1.58–1.74 versus 1.92). From P. aporus , we distinguish P. costatus by the total lamellae on one hand (49–58 versus 36–48). From P. chalcorhabdus , we distinguish P. costatus by the relative width of canthal iii (1.82– 1.90 versus 1.98–2.05). From P. curtissi , we distinguish P. costatus by the dots arranged in bars in the lateral areas (present versus absent), the midbody scale rows (39–43 versus 32–38), the total lamellae on one hand (49–58 versus 32–39), the relative length of digits on one hindlimb (31.5–37.8 versus 20.8–28.1), the relative longest finger length (5.53–6.66 versus 3.59–4.54), and the relative distance between the eye and naris (5.08–5.50 versus 4.02–5.03). From P. diastatus , we distinguish P. costatus by the total lamellae on one hand (49–58 versus 35–41), the relative length of digits on one hindlimb (31.5–37.8 versus 21.5–27.4), the relative longest finger length (5.53–6.66 versus 3.48–4.87), and the relative distance between the eye and naris (5.08–5.50 versus 4.06–4.94). From P. emys , we distinguish P. costatus by the total strigae on ten scales (158–217 versus 238–311), the relative frontal width (56.2– 67.4 versus 67.7–74.5), and the relative angled subocular width (2.36–2.81 versus 2.12–2.20). From P. hylonomus , we distinguish P. costatus by the dots arranged in bars in the lateral areas (present versus absent), the adult SVL (83.6–107 versus 59.3–76.5), the total lamellae on one hand (49–58 versus 34–47), the relative length of digits on one hindlimb (31.5–37.8 versus 22.8–28.2), the relative longest finger length (5.53–6.66 versus 4.47–5.27), the relative distance between the eye and naris (5.08–5.50 versus 4.03–4.98), and the relative width of canthal iii (1.82– 1.90 versus 1.95–2.03). From P. lanceolatus sp. nov., we distinguish P. costatus by the relative distance between the eye and naris (5.08–5.50 versus 4.58–5.05). From P. lapierrae sp. nov., we distinguish P. costatus by the midbody scale rows (39–43 versus 33–38), the total lamellae on one hand (49–58 versus 38–47), the total strigae on ten scales (158–217 versus 228–231), the relative length of digits on one hindlimb (31.5–37.8 versus 24.3–30.9), the relative cloacal width (7.27–8.51 versus 8.55–8.81), the relative prefrontal width (3.97–4.67 versus 4.73–4.75), the relative longest finger length (5.53–6.66 versus 4.49–4.55), the relative head width (68.3–76.8 versus 77.7–78.1), the relative frontal width (56.2–67.4 versus 77.6–79.0), and the relative nasal width (1.58–1.74 versus 1.81). From P. leionotus , we distinguish P. costatus by the total lamellae on one hand (49–58 versus 43–48) and the relative frontal width (56.2–67.4 versus 68.7–81.2). From P. marcanoi , we distinguish P. costatus by the total lamellae on one hand (49–58 versus 36–44). From P. melanchrous , we distinguish P. costatus by the relative nasal height (1.02– 1.28 versus 0.897 –0.952). From P. neiba , we distinguish P. costatus by the relative distance between the eye and naris (5.08–5.50 versus 4.51–5.01). From P. nesobous , we distinguish P. costatus by the relative prefrontal width (3.97–4.67 versus 4.74–4.81), the relative distance between the eye and naris (5.08–5.50 versus 5.62–5.73), and the relative width of canthal iii (1.82–1.90 versus 2.01–2.12). From P. oreistes , we distinguish P. costatus by the area of the nasal scale by the SVL (1.59–2.03 versus 1.06–1.57) (see Remarks). From P. psychonothes , we distinguish P. costatus by the total lamellae on one hand (49–58 versus 37–44). From P. saonae , we distinguish P. costatus by the total lamellae on one hand (49–58 versus 40–42), the relative length of digits on one hindlimb (31.5–37.8 versus 26.5–29.8), the relative mental width (1.66–2.00 versus 1.52), the relative longest finger length (5.53–6.66 versus 5.01), the relative frontal width (56.2–67.4 versus 72.5), the relative nasal height (1.02–1.28 versus 1.01), the relative distance between the eye and naris (5.08–5.50 versus 6.43), the relative width of canthal iii (1.82–1.90 versus 1.99), and the relative angled subocular width (2.36–2.81 versus 2.31). From P. semitaeniatus sp. nov., we distinguish P. costatus by the total lamellae on one hand (49–58 versus 34–46), the relative rostral height (1.78–2.26 versus 2.41–2.63), the relative head width (68.3–76.8 versus 58.8–63.8), the relative distance between the eye and naris (5.08–5.50 versus 4.61), the relative width of canthal iii (1.82–1.90 versus 1.80), and the relative nasal width (1.58–1.74 versus 1.51). From P. unicolor sp. nov., we distinguish P. costatus by the adult SVL (83.6–107 versus 67.6), the total lamellae on one hand (49–58 versus 48), the total strigae on ten scales (158–217 versus 144), the relative distance between angled subocular and mouth (0.582 –0.916 versus 0.533), the relative prefrontal width (3.97–4.67 versus 4.69), the relative largest supraocular width (1.93–3.01 versus 3.12), the relative distance between the eye and naris (5.08–5.50 versus 5.52), the relative width of canthal iii (1.82–1.90 versus 1.79), the relative angled subocular width (2.36–2.81 versus 2.90), and the relative nasal width (1.58–1.74 versus 2.00).

Description of holotype. MCZ R-3606. An adult male; SVL 94.4 mm; tail slightly laterally compressed, broken, 16.3 mm (17.3% SVL); axilla-to-groin distance 51.3 mm (54.3% SVL); head length 18.9 mm (20.0% SVL); head width 12.9 mm (13.7% SVL); head width 68.3% head length; diameter of orbit 3.23 mm (3.42% SVL); horizontal diameter of ear opening 1.02 mm (1.08% SVL); vertical diameter of ear opening 0.88 mm (0.932% SVL); shortest distance between angled subocular and lip 0.70 mm (0.742% SVL); shortest distance between the ocular and auricular openings 8.34 mm (8.83% SVL); largest supraocular width 1.88 mm (1.99% SVL); cloacal width 7.56 mm (8.01% SVL); prefrontal width 4.41 mm (4.67% SVL); postmental width 2.62 mm (2.78% SVL); frontal width 67.4% frontal length; angled subocular height 0.65 mm (0.689% SVL); shortest distance between the eye and naris 4.98 mm (5.28% SVL); canthal iii width 1.73 mm (1.83% SVL); angled subocular width 2.53 mm (2.68% SVL); frontonasals and prefrontal fused into a single large plate with an irregular posterior margin, much wider than long, bordered by rostral complex plate, 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 much wider than long; parietal separated from supraoculars by 1 st and 2 nd temporals and frontoparietal (left)/(right); 2 loreals (left)/(right); 1 st loreal wider than high (left)/higher than wide (right), in contact with postnasal, rostral complex, prefrontal/frontonasal complex, 1 st median ocular, canthal iii, 2 nd loreal, additional 2 scales preventing contact from 3 rd supralabial, and supralabial 2 (left)/postnasal, rostral complex, prefrontal/frontonasal complex, 1 st median ocular, canthal iii, 2 nd loreal, and supralabial 2 (right); 2 nd loreal shorter than 1 st, wider than high (left)/ shorter than 1 st, approximately as high as wide (right), excluded from contact with supraocular by canthal iii (left)/ (right); final loreal posteriorly bordering the upper and lower preoculars and 1 additional scale (left)/upper and lower preoculars (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 (left)/10 (right) median oculars, 1 st contacting the prefrontal (left)/(right); 1 upper preocular (left)/(right); an irregular anterior supraciliary (left)/(right); 5 (left)/6 (right) lateral oculars; 5 temporals (left)/(right); 2 suboculars (left)/(right); posterior subocular large and elongate (left)/(right); anterior subocular small (left)/(right); mental fused with postmental; 4 pairs of enlarged chin shields, followed by 1 pair of reduced chin shields; 1 st pair in contact with one another; 2 nd (damaged) to 5 th pair separated by 1–5 scales; 94 transverse rows of dorsal scales from interoccipital to base of tail; 89 transverse rows of ventral scales from mental to vent; 43 scales around midbody; keelless and striate dorsal body and caudal scales; striate ventral scales; 201 total strigae counted on ten scales.

Color (in alcohol): faded, dorsal surface of head tan, patternless; lateral surfaces of head grading from tan to yellow-cream with darker brown eye masks; dorsal surfaces of the body are medium brown with irregular, small, darker brown flecks; dorsal surface of tail the same as the body; lateral areas medium brown grading to yellow-cream with darker brown and off-white spots arranged in bars; dorsal surfaces of the limbs are golden tan with darker brown mottling; lateral and ventral areas of the limbs fade to yellow-cream, patternless; ventral surfaces of the head, body, and tail are yellow-cream, patternless.

Variation. The majority of the examined material has a dorsal pattern of irregular flecks or dots with only ANSP 38559 showing no pattern and MCZ R-134264 having the dots on its dorsum arranged in vague chevrons. MCZ R-134264 also has irregular, darker areas on its head scales, whereas the other specimens have patternless heads. All specimens other than the holotype have either dots in the longitudinal paramedian series or complete or broken longitudinal paramedian lines. Dots in the lateral band are arranged into bars on all specimens. Measurements and other morphological data for the holotype and other examined material are presented in Table 1 .

Distribution. Panolopus costatus is distributed in the western Tiburon Peninsula of Haiti at elevations of 0– 1210 m (Fig. 49). It has an extent of occurrence of ~ 3,900 km 2.

Ecology and conservation. Past literature accounts of ecological data for this species conflate multiple species and therefore cannot be used. Most individuals were found under objects on the ground, but one juvenile individual ( ANSP 38559 ) was found in a bromeliad in a tree ( SBH, field notes) .

We consider the conservation status of Panolopus costatus 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. Past literature accounts of ecological data for this species conflate multiple species and therefore cannot be used. A litter size of 2–6 has been recorded in Panolopus costatus sensu stricto (SBH, field data).

Etymology. The species name is derived from the Latin adjective meaning “ribbed,” in apparent allusion to the series of “numerous blackish brown vertical bars” on the sides of the body as described by Cope for the type specimen.

Remarks. Schwartz (1964) discussed the 19 th Century synonyms: Celestus phoxinus , Diploglossus ohlendorffi , and Diploglossus nuchalis . The first was collected by Weinland at the same place and about the same time as the type of C. costatus . Schwartz examined the type of C. phoxinus and concurred with Garman (1887) that it is C. costatus (here, Panolopus costatus sensu stricto). Descriptions of the other two were clear enough to assign them as synonyms of C. costatus (sensu lato) as well, but they lacked specific localities and sufficient details to assign them to the subspecies of Schwartz (1964) or to our species. Schwartz (1964) concluded (and we agree) that these three names should be direct synonyms of “ Celestus c. costatus ” (here, P. costatus sensu stricto) “until additional information becomes available.”

Prior to this work, Panolopus costatus was reported to have 11 subspecies: P. c. aenetergum , P. c. chalcorhabdus , P. c. costatus , P. c. emys , P. c. leionotus , P. c. melanchrous , P. c. neiba , P. c. nesobous , P. c. oreistes , P. c. psychonothes , and P. c. saonae . All of these subspecies are elevated to the species level herein. Further analyses of museum specimens that have been recorded as P. costatus should be undertaken to assign all individuals to the correct species.

Panolopus costatus and P. oreistes cannot be morphologically separated based on our standard suite of characters, however, they can be separated by the area of the nasal scale by the SVL (1.59–2.03 [n=4] versus 1.06–1.57 [n=14]).

FIGURE 55. (A–F) Panolopus costatus (MCZ R-3606, holotype), SVL 94.4 mm.

Panolopus costatus was 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 P. oreistes . Based on our timetree (Fig. 4), P. costatus diverged from its closest relative 2.43 Ma, consistent with typical species of vertebrates (> 0.7 Ma; Hedges et al. 2015). Panolopus costatus was recognized as a distinct species by our ASAP analysis.

FIGURE 56. Panolopus costatus (ANSP 38561, SBH 268996), in life. From ca. 1 km NE Tiburon, Sud Department, Haiti. Photo by SBH.