Polychrus marmoratus (Linnaeus)

Figures 1c, d.

Lacerta marmorata Linnaeus 1758: 208 . Type locality “Hispania.” Restricted to the vicinity of Paramaribo, Suriname by Hoogmoed (1973).

Polychrus marmoratus – Cuvier 1817: 41.

Psilocercus marmoratus – Wagler 1821: 341.

Agama marmorata – Daudin 1802: 433.

Polychrus marmoratus marmoratus – Burt and Burt, 1933: 41.

Referred specimens: Skeletal material: Suriname AMNH 141130, AMNH 148544 male, AMNH 141084, UF 56618 (Guyana or Suriname), UF 60914 female, UF 68102. Alcohol material: (n = 32). Guyana, Demerara, (6.733 -57.983) FMNH 3294, Dunoon Demerara River UMMZ 47632, 53965, 47630, 47751, 47752, 47753, 47754; Cabacalli Island Moruco River (6.78915 -58.182949) UMMZ 56467, 56468; Wismar (5.9999 -58.30001) UMMZ 76685; Kartabo (6.377459 -58.706761) UMMZ 47631, CM S4244, S4245, S5361; no specific locality; MCZ R-24391, UMMZ 47633, 55839, 55856; Suriname, Paramaribo (5.442523 -55.09896); MCZ R-8255, CM 44369, 52384, 52385, 44362–44368, 49531–32.

Diagnosis: Loreal usually fragmented into three or four scales; supranasal scale frequently (about 0.50) makes contact with loreal. One to three internasals. Vertebral rows 95–117; scales around mid-body 66–90. Snout length is 0.58 of orbit length. Lamellae on fourth toe 35–44. Usually three scales between first canthals, and five between the second; nasal contacts first two upper labials. Total femoral pores 8–19. Many multicarinate paravertebral scales; paravertebrals not much larger than laterals. The number of supraocular rows usually six (rarely 5 or 7). Scales on snout and supraoculars finely striated to smooth with tiny tubercles. Scales on anterior surface of humerus keeled; a reduced gular crest starts at the level of the first or second lower labial.

Variation: Females are significantly larger than males. Females SVL X = 114.5 (n = 29), males SVL X = 102.9 (n = 11) (p = <0.05, 29 df). Tail length: females X = 292.3 (n = 16), males X = 272 (n = 10). Forelegs X = 0.40 of SVL; r = 0.35–0.47; hind legs X = 0.52 of SVL, r = 0.45–0.57.

Rostral broader than tall, contacts two or three postrostrals. Scales on snout juxtaposed. Nasal with large nare, one or two supranasal above nasal on the snout, separated by 3–5 scales. Supranasal frequently makes contact with loreal. First pair of canthals (most anterior pair) separated by three (rarely two) scales; second pair of canthals separated by 4–5 scales (usually five). Semicircle scales 5–9, the total bilateral average 14.4; usually separated by a single scale (or scale row) anteriorly, and a double row posteriorly. Ciliaries 10–13, usually with two keels. Supraocular scales polygonal to round in five or six rows between ciliaries and semicircle scales, first row or first two rows of supraoculars with keels (first row sometimes appears to be a second row of ciliaries); supraoculars highly variable in number (31–44) and in five or six rows (rarely seven). A prenasal scale usually separates the postrostral from the nasal. The nasal is usually square and in contact with the first two upper labials, sometimes in narrow contact with the third upper labial. Loreal usually in two or three parts, anterior scale quadrangular and posterior triangular scale. Loreal usually contacts upper labials 2–3–4, sometimes 2–3 or 3–4; first canthal usually makes contact with loreal. Upper labials numbered 5–9 per side, usually six; bilateral average for total upper labials 14.7; upper labial under middle of eye usually fifth, or 4–5, or 5–6. Lower labials 6–9, usually 7; total bilateral average for lower labials 14.1 scales. Orbital scales: preorbitals two; suborbitals 2–4, usually 2–3; postorbitals usually two, sometimes 3 or 4. Temporal scales usually in eight vertical rows between post orbitals and tympanum, separated from parietal scales by a row of 4–5 enlarged supratemporals. Gulars (counted between tympani 42–55 (X = 47.0)), rows of gulars separated by numerous micro-scales that vary in size. Dorsal scales around mid-body X = 78.5 (r = 66–90, SD = 8.71). Vertebrals and paravertebrals in 10–14 rows; slightly enlarged, pentagonal, and keeled; radually become elongate and ovate laterally often losing the keels; and transition into sharply keeled, pointed, imbricate ventrals. Scales similar to the ventrals in size and shape extend onto the anal plate. Vertebral scales rows X = 108.2 (r = 95–113, SD = 5.17) between the occiput and posterior edge of hind legs. Lamellae on fourth finger 25–35 (X = 30.5 SD = 3.18), lamellae on fourth toe 30–43 (X = 38.69, SD = 3.01). Total pores 8–19 (X = 14.3, SD = 3.31). Scales on tail pentagonal, heavily keeled, and imbricate. Scales on limbs keeled, imbricate, and slightly more ovate near the body, than distally.

Coloration: In preservative most specimens are a uniform brown-tan with black pigmented eye stripes and labial seams. In life, coloration is highly variable and can change in less than a minute from green to brown. See Figures 1c,d.

Distribution: We have only documented this species from Guyana and Suriname, but it may be expected to occur in French Guyana and northern Brazil.

Natural history: Hoogmoed (1973) described it as being diurnal, arboreal, and omnivorous; females lay 4– 6 eggs in July and August. It is capable of rapid color change from bright green to brown. Comments on its natural history in the literature are deeply entangled with other members of the species group.

Comparisons: Distinguished from Polychrus auduboni by numerous multicarinate paravertebral scales (few or none in P. auduboni); paravertebrals not much larger than laterals; a loreal fragmented in two or more parts (as opposed to one or two in P. auduboni); a nasal that is pentagonal and usually contacts the first upper labial (it usually does not in auduboni); 8–19 (X = 14.32, SD = 3.31) femoral pores ( auduboni has 17–28, X = 21.4, SD = 2.91); the supranasal often makes contact with the loreal (in auduboni it rarely does so).