Panolopus marcanoi ( Schwartz & Incháustegui 1976 )

Schools, Molly & Hedges, Blair, 2024, A new forest lizard fauna from Caribbean islands (Squamata, Diploglossidae, Celestinae), Zootaxa 5554 (1), pp. 1-306 : 183-187

Panolopus marcanoi ( Schwartz & Incháustegui 1976)

Pico Duarte Forest Lizard

(Fig. 67–68)

FIGURE 67. (A–F) Panolopus marcanoi (USNM 197299, holotype), SVL 73.0 mm.

Diploglossus marcanoi Schwartz & Incháustegui, 1976:242 . Holotype: USNM 197299 , collected by Sixto J. Incháustegui from Valle de Bao , Santiago Province, Dominican Republic, on 29 December 1972 (19.0833, -71.0333; 1800 m).

Celestus marcanoi — Schwartz & Henderson, 1988:99.

Celestus marcanoi — Schwartz & Henderson, 1991:376.

Celestus marcanoi — Powell et al., 1999:105.

Panolopus marcanoi — Schools & Hedges, 2021:230,

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

Material examined (n=23). DOMINICAN REPUBLIC. Santiago. ANSP 38648 , Richard Thomas, Herman Dominicia, and S. Blair Hedges, La Lagus, 3 August 1993 ; ANSP 38649 , Richard Thomas, Herman Dominicia, and S. Blair Hedges, Loma los Baderos , east slope, 2 August 1993 ; ANSP 38650–62 , Richard Thomas, Herman Dominicia, and S. Blair Hedges, Valle de Bao , 31 July 1993 ; KU 226551–4 , Valle de Bao, Cordillera Central (road to Pico Duarte), 29 December 1971 ; SBH 193288–9 , S. Blair Hedges, Richard Thomas, and Herman Dominicia, Valle de Bao , 31 July 1993 ; SBH 193293 , S. Blair Hedges, Richard Thomas, and Herman Dominicia, Valle de Bao , 31 July 1993 ; USNM 197299 , Sixto J. Incháustegui, Valle de Bao, Cordillera Central , 29 December 1972 .

Diagnosis. Panolopus marcanoi has (1) a dorsal pattern of irregular dots/dots in chevrons, (2) head markings present, (3) markings in the longitudinal paramedian area present, (4) dots arranged in bars in the lateral band present, (5) an adult SVL of 64.6–85.8 mm, (6) ventral scale rows, 89–102, (7) midbody scale rows, 38–45, (8) total lamellae on one hand, 36–44, (9) total strigae on ten scales, 141–254, (10) relative length of all digits on one hindlimb, 26.3– 31.9 %, (11) relative distance between the angled subocular and mouth, 0.451 –0.755 %, (12) relative eye length, 3.03–3.93 %, (13) relative forelimb length, 19.9–23.6 %, (14) relative ear width, 0.936–2.25 %, (15) relative rostral height, 1.96–2.38 %, (16) relative head length, 15.7–19.9 %, (17) relative mental width, 1.75–2.33 %, (18) relative postmental width, 2.46–3.24 %, (19) relative cloacal width, 7.18–9.56 %, (20) relative prefrontal width, 4.19–5.19 %, (21) relative largest supraocular width, 2.47–3.33 %, (22) relative longest finger length, 4.75–6.68 %, (23) relative distance between the ear and eye, 7.02–8.81 %, (24) relative head width, 68.4–77.9 %, (25) relative frontal width, 59.0–73.0 %, (26) relative nasal height, 1.07–1.28 %, (27) relative angled subocular height, 0.505 –0.793 %, (28) relative distance between the eye and naris, 4.68–5.82 %, (29) relative canthal iii length, 1.60–2.23 %, (30) relative angled subocular width, 2.19–3.14 %, and (31) relative nasal length, 1.64–1.96 %. The species stem time is 1.87 Ma and the species crown time is 0.07 Ma (Fig. 4).

We distinguish Panolopus marcanoi from the other species of Panolopus based on a complex of traits. From Panolopus aenetergum , we distinguish P. marcanoi by the head markings (present versus absent), the longitudinal paramedian lines (present versus absent), the ventral scale rows (89–102 versus 80–86), the midbody scale rows (38–45 versus 35–36), the total strigae on ten scales (141–254 versus 267), the relative mental width (1.75–2.33 versus 1.63), the relative prefrontal width (4.19–5.19 versus 4.15), the relative frontal width (59.0–73.0 versus 88.2), the relative angled subocular height (0.505 –0.793 versus 1.08), the relative distance between the eye and naris (4.68–5.82 versus 4.35), and the relative angled subocular width (2.19–3.14 versus 2.07). From P. aporus , we distinguish P. marcanoi by the head markings (present versus absent). From P. chalcorhabdus , we distinguish P. marcanoi by the angled subocular width by the angled subocular height (3.37–5.36 versus 2.77–3.28) (see Remarks). From P. costatus , we distinguish P. marcanoi by the total lamellae on one hand (36–44 versus 49–58). From P. curtissi , we distinguish P. marcanoi by the dorsal pattern (irregular dots/dots in chevrons versus absent/irregular flecks), the head markings (present versus absent), the dots arranged in bars in the lateral areas (present versus absent), and the relative longest finger length (4.75–6.68 versus 3.59–4.54). From P. diastatus , we distinguish P. marcanoi by the dorsal pattern (irregular dots/dots in chevrons versus absent/irregular flecks), the head markings (present versus absent), and the longitudinal paramedian lines (present versus absent). From P. emys , we distinguish P. marcanoi by the dorsal pattern (irregular dots/dots in chevrons versus absent/irregular flecks), the head markings (present versus absent), the adult SVL (64.6–85.8 versus 99.0–113), and the relative nasal width (1.64–1.96 versus 1.23–1.58). From P. hylonomus , we distinguish P. marcanoi by the dorsal pattern (irregular dots/dots in chevrons versus absent/irregular flecks), the head markings (present versus absent), and the dots arranged in bars in the lateral areas (present versus absent). From P. lanceolatus sp. nov., we distinguish P. marcanoi by the relative nasal height (1.07–1.28 versus 0.904–1.06). From P. lapierrae sp. nov., we distinguish P. marcanoi by the relative longest finger length (4.75–6.68 versus 4.49–4.55), the relative frontal width (59.0–73.0 versus 77.6–79.0), and the relative angled subocular height (0.505 –0.793 versus 0.838 –0.978). From P. leionotus , we distinguish P. marcanoi by the head markings (present versus absent), and the adult SVL (64.6–85.8 versus 86.3–105). From P. melanchrous , we distinguish P. marcanoi by the adult SVL (64.6–85.8 versus 93.2–124), the total lamellae on one hand (36–44 versus 47–58), and the relative nasal height (1.07–1.28 versus 0.897 –0.952). From P. neiba , we distinguish P. marcanoi by the head markings (present versus absent) and the total lamellae on one hand (36–44 versus 45–49). From P. nesobous , we distinguish P. marcanoi by the head markings (present versus absent), the total lamellae on one hand (36–44 versus 50–59), and the relative length of digits on one hindlimb (26.3–31.9 versus 35.1). From P. oreistes , we distinguish P. marcanoi by the relative nasal height (1.07–1.28 versus 0.878–1.06). From P. psychonothes , we distinguish P. marcanoi by the relative angled subocular height (0.505 –0.793 versus 0.803 –0.952). From P. saonae , we distinguish P. marcanoi by the dorsal pattern (irregular dots/dots in chevrons versus absent), the head markings (present versus absent), the longitudinal paramedian lines (present versus absent), the adult SVL (64.6–85.8 versus 90.9–98.3), the relative mental width (1.75–2.33 versus 1.52), the relative postmental width (2.46–3.24 versus 2.43), the relative prefrontal width (4.19–5.19 versus 4.14), the relative nasal height (1.07–1.28 versus 1.01), the relative angled subocular height (0.505 –0.793 versus 0.847), and the relative distance between the eye and naris (4.68–5.82 versus 6.43). From P. semitaeniatus sp. nov., we distinguish P. marcanoi by the relative rostral height (1.96–2.38 versus 2.41–2.63), the relative head width (68.4–77.9 versus 58.8–63.8), the relative distance between the eye and naris (4.68–5.82 versus 4.61), and the relative nasal width (1.64–1.96 versus 1.51). From P. unicolor sp. nov., we distinguish P. marcanoi by the dorsal pattern (irregular dots/dots in chevrons versus absent), the head markings (present versus absent), the total lamellae on one hand (36–44 versus 48), the relative length of digits on one hindlimb (26.3–31.9 versus 36.8), the relative mental width (1.75–2.33 versus 1.73), the relative frontal width (59.0–73.0 versus 58.2), the relative angled subocular height (0.505 –0.793 versus 0.814), and the relative nasal width (1.64–1.96 versus 2.00).

Description of holotype. USNM 197299. An adult male; SVL 73.0 mm; tail nearly cylindrical, broken in life midway, regenerated, 77.8 mm (107% SVL); axilla-to-groin distance 42.2 mm (57.8% SVL); forelimb length 16.9 mm (23.2% SVL); hindlimb length 24.7 mm (33.8% SVL); head length 13.9 mm (19.0% SVL); head width 10.4 mm (14.2% SVL); head width 74.8% head length; diameter of orbit 2.87 mm (3.93% SVL); horizontal diameter of ear opening 1.64 mm (2.25% SVL); vertical diameter of ear opening 1.52 mm (2.08% SVL); length of all toes on one foot 23.3 mm (31.9% SVL); shortest distance between angled subocular and lip 0.48 mm (0.658% SVL); shortest distance between the ocular and auricular openings 6.43 mm (8.81% SVL); longest finger length 4.88 mm (6.68% SVL); largest supraocular width 2.32 mm (3.18% SVL); cloacal width 6.98 mm (9.56% SVL); postmental width 2.05 mm (2.81% SVL); prefrontal width 3.79 mm (5.19% SVL); frontal width 72.5% frontal length; nasal height 0.84 mm (1.15% SVL); angled subocular height 0.56 mm (0.767% SVL); shortest distance between the eye and naris 3.79 mm (5.19% SVL); canthal iii width 1.54 mm (2.11% SVL); angled subocular width 2.29 mm (3.14% SVL); nasal width 1.23 mm (1.68% SVL); rostral 2.30X 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 irregular 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 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 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); 2 nd loreal posteriorly bordering the lower preocular (left)/(right); canthal iii wider than high (left)/(right), contacting 1 st median ocular, anterior supraciliary, lower preocular, and 1 st and 2 nd loreals (left)/(right); 10 median oculars (left)/(right), 1 st and 2 nd contacting the prefrontal (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); 10 (left)/9 (right) supralabials, 6 to level below center of eye (left)/(right); 9 infralabials (left)/(right), 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; 96 transverse rows of dorsal scales from interoccipital to base of tail; 96 transverse rows of ventral scales from mental to vent; 40 scales around midbody; 5 digits; finger lengths 3>4>2>5>1; 11 lamellae under longest finger (left)/(right); 44 total lamellae on one hand; toe lengths 4>3>5>2>1; 16 (right) lamellae under longest toe; keelless and striate dorsal body and caudal scales; smooth ventral scales; 173 total strigae counted on ten scales.

Color (in alcohol): dorsal surface of head brown-gray with irregular dark brown spots; lateral surfaces of head grading from brown-gray to muted brown-gray with darker brown eye masks and other darker brown areas on the labial scales and sides of neck; dorsal surfaces of the body are brown-gray with many markings vaguely in longitudinal paramedian series that become more random posteriorly; dorsal surface of tail brown-gray with many markings vaguely continuing the longitudinal paramedian series; lateral areas grade from brown-gray to muted brown-gray with dots in vertical lines; dorsal surfaces of the limbs are dark brown with paler gray mottling; lateral and ventral areas of the limbs fade to muted gray-brown; ventral surfaces of the head, body, and tail are muted gray-brown with a few darker flecks under the chest and tail.

Variation. The material examined resembled the holotype in dorsal pattern. All specimens examined have a heavy pattern of either irregular dots or dots arranged into broken chevrons. All specimens examined have large, irregular dark markings on their head whereas several specimens also possess darker outlines on their head scale borders. All examined material possess markings in the longitudinal paramedian area in the form of complete or broken longitudinal paramedian lines. Of the specimens examined, all 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.

FIGURE 68. Panolopus marcanoi (ANSP 38662, SBH 193346), SVL 73.5 mm, in life. From Valle de Bao, Santiago Province, Dominican Republic. Photograph by SBH.

Distribution. Panolopus marcanoi is distributed in the Cordillera Central of the Dominican Republic where it is found at 1500–1800 m (Fig. 50).

Ecology and conservation. The type series of this species was collected in a high-elevation river valley where two creeks were present and the soil was relatively dry. They were collected from under rocks in the early morning, when they were close to immobile, presumably because of the cool temperatures (frost present on the ground). Schwartz & Incháustegui (1976) noted that Valle de Bao (the type locality of Panolopus marcanoi ) is less favorable for diurnal activity than other areas of the Cordillera Central. These lizards were relatively common (approximately one lizard collected every ten rocks).

The IUCN Redlist ( IUCN 2023) considers the conservation status of Panolopus marcanoi to be of Least Concern, because “although the distribution is limited (with an extent of occurrence of 120 km 2), there are no current major threats, and its distribution occurs in one protected area.” Studies are needed to determine the health of remaining populations and threats to the survival of the species.

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

Etymology. The species name refers to Dr. Eugenio de Jesús Marcano F., the organizer of the two expeditions that led to the discovery of the species.

Remarks. Panolopus marcanoi and P. chalcorhabdus 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 (3.37–5.36 [n=18] versus 2.77–3.28 [n=5]).

Panolopus marcanoi was included in our genetic dataset and has significant support in our ML and Bayesian analyses at the crown node. However, the stem node placing P. marcanoi within Panolopus has support values of 76% and 57% in our ML and Bayesian analyses, respectively. Schools et al. (2022) used genomic data to place P. marcanoi outside of P. unicolor sp. nov., P. diastatus , P. leionotus , P. marcanoi , P. neiba , and P. semitaeniatus sp. nov. with support values of 94% and 92% in their ML and Bayesian analyses, respectively, at the stem node. Based on our timetree (Fig. 4), P. marcanoi diverged from its closest relative 1.87 Ma, consistent with typical species of vertebrates (> 0.7 Ma; Hedges et al. 2015). Panolopus marcanoi was recognized as a distinct species by our ASAP analysis.