Spondylurus caicosae, Hedges & Conn, 2012

Hedges, S. Blair & Conn, Caitlin E., 2012, A new skink fauna from Caribbean islands (Squamata, Mabuyidae, Mabuyinae) 3288, Zootaxa 3288 (1), pp. 1-244 : 145-149

Spondylurus caicosae sp. nov.

Caicos Islands Skink

( Figs. 54B , 55B , 59 )

Mabuya mabouia — Barbour, 1935:129 (part).

Mabuya mabouya sloanii — Dunn, 1936:546 (part).

Mabuya sloanii — Grant, 1937:520 (part).

Mabuya mabouia — Barbour, 1937:147 (part).

Mabuya mabouya sloanei — Schwartz & Henderson, 1988:151 (part).

Mabuya mabouya sloanei — Schwartz & Henderson, 1991:457 (part).

Mabuya bistriata — Powell et al., 1996:82 (part).

Mabuya sloanii — Mayer & Lazell, 2000:883 (part).

Mabuya sloanii — Henderson & Powell, 2009:293 (part).

Holotype. AMNH R-80126, an adult male, collected 10 February 1953 on Long Cay off South Caicos, Caicos Islands, Turks and Caicos, by G. B. Rabb.

Paratypes (n = 98). Caicos Islands, Turks and Caicos. AMNH R 80125, AMNH R80127–30 (paratopotypes), same collection data as holotype; MCZ R-42061–62, J. C. Greenway, Ambergris Cay, March 1936; MCZ R- 182881, G. Mitchell, Long Cay, 12 May 2000; MCZ R-183341, N. C. Mitchell, Long Cay, 28 October 2000; MPM 21932–37 , 0.5 miles E Cockburn Harbor, South Caicos, 14 January 1961 (no collector available); UMMZ 117392– 93 , G. B. Rabb and C. L. Giovannoli, West Caicos, 4 February 1953; UMMZ 117394–96 , G. B. Rabb and C. L. Giovannoli, West Cay of Six Hill Cays , 12 February 1953; USNM 81448 , West Caicos, 4 August 1930 (no collector available). The following were all collected by A. Schwartz and colleagues: KU 242093–94 , Bay Cay, 24 February 1972; KU 242095, Jacksonville, East Caicos, 22 January 1972; KU 242096, Little Ambergris Cay, 28 March 1972; KU 242097 (12 January 1961), KU 242116–29 (12–14 January 1961), KU 242130–66 (14 January 1961), KU 242167 (22 March 1961), vicinity of Cockburn Harbor , Long Cay ; KU 242098, Bambarra, Middle Caicos, 25 January, 1972; KU 242099, Conch Bar, Middle Caicos, 31 January 1972; KU 242100–07 , Kew , North Caicos, 6–21 February, 26 May 1972; KU 242108–09 , vicinity of Belle Field Landing , North Caicos, 3 April 1974; KU 242110, Wades Green Plantation , North Caicos, 16 February 1972; KU 242111, near Whitby , North Caicos, 26 April 1974; KU 242112, Bottle Creek , North Caicos, 25 May 1971; KU 242113, Blue Hills, Providenciales, 22 February 1972; KU 242114, near Third Turtle Inn , Providenciales, 20 March 1972; KU 242115, Leeward, Providenciales, 16 March 1976; KU 242168–69 , East Six Hill Cays , Caicos Islands, 18 January 1961 .

Diagnosis. Spondylurus caicosae sp. nov. is characterized by (1) maximum SVL in males, 72.4 mm; (2) maximum SVL in females, 77.6 mm; (3) snout width, 2.14–3.66% SVL; (4) head length, 15.0–18.5% SVL; (5) head width, 10.9–14.8% SVL; (6) ear length, 1.06–2.10% SVL; (7) toe-IV length, 7.86–12.2% SVL; (8) prefrontals, two; (9) supraoculars, three (5%), four (95%); (10) supraciliaries, three (16%), four (84%); (11) frontoparietals, two; (12) supralabial below the eye, four (5%), five (86%), six (7%), seven (2%); (13) nuchal rows, one (9%), two (91%); (14) dorsals, 56–65; (15) ventrals, 56–72; (16) dorsals + ventrals, 113–134; (17) midbody scale rows, 27–32; (18) finger-IV lamellae, 9–14; (19) toe-IV lamellae, 13–19; (20) finger-IV + toe-IV lamellae, 22–32; (21) supranasal contact, Y (46%), N (54%); (22) prefrontal contact, N; (23) supraocular-1/frontal contact, Y (38%), N (62%); (24) parietal contact, Y; (25) pale middorsal stripe, Y; (26) dark dorsolateral stripe, Y; (27) dark lateral stripe, Y; (28) pale lateral stripe, Y (weak); and (29) palms and soles, dark ( Tables 3–5).

Within the Genus Spondylurus , S. caicosae sp. nov. differs from S. anegadae sp. nov., S. culebrae sp. nov., S. monae sp. nov., S. monitae sp. nov., S. semitaeniatus , and S. sloanii by having a lower dark dorsolateral stripe/ middorsal stripe ratio (0.238 –0.805 versus 0.874–3.79 in those other species). It is separated from S. anegadae sp. nov. and S. macleani by having distinct dorsal spots posterior to the dark dorsolateral stripes (versus essentially no dorsal pattern posterior to the dark dorsolateral stripes in those other species). It is separated from S. magnacruzae sp. nov. and S. spilonotus by having fewer midbody scale rows (27–32 versus 34 in those other species). From S. fulgidus , it is separated by having dark lateral stripes with paler (included) spots and irregular pale lateral stripes that extend only half-way (or less) to hindlimbs, ending in vertical bars (versus solid dark lateral stripes and pale lateral stripes continuous to the hindlimbs in S. fulgidus ) and by having a lower number of supraciliaries (3–4 versus five in S. fulgidus ). From S. lineolatus , it differs by having a longer head (head length 15.0–18.5% SVL versus 12.9–14.4% SVL in S. lineolatus ) and by having two dark dorsolateral stripes and two dark lateral stripes (versus 10 dark stripes in S. lineolatus ). It is distinguished from S. monitae sp. nov. by having straighter dark dorsolateral stripes (versus dark dorsolateral stripes that bow inward on the parietal scales in S. monitae sp. nov.). It differs from S. nitidus in having a dark lateral stripe that extends only half-way (or less) to hindlimbs, ending in vertical bars (versus extending mostly to hindlimbs, albeit faintly, in S. nitidus ). It differs from S. turksae sp. nov. in having a shorter ear (ear height 0.73–1.52% SVL versus 1.57–1.87% SVL), a narrower pale dorsolateral stripe (1.02–1.73% SVL versus 1.98–2.33% SVL), and a dark lateral stripe that extends only half-way (or less) to

Besides those non-overlapping differences, there are frequency differences that distinguish Spondylurus caicosae sp. nov. from other species. It differs from S. nitidus and S. turksae sp. nov. in being smaller (<77.6 mm SVL in 99 specimens versus seven of 13 S. nitidus > 79.6 mm SVL and three of seven S. turksae sp. nov. > 77.7 mm SVL). From S. culebrae sp. nov., S. haitiae sp. nov., S. magnacruzae sp. nov., S. monae sp. nov., and S. spilonotus , it differs by having fewer supralabial scales (supralabial four or five below the eye in 91% of specimens versus supralabial six or seven below the eye in 83–100% of specimens belonging to those other species). It differs from S. haitiae sp. nov. by having fewer ventral scales (56–68 in 98% of specimens versus 69–72 in S. haitiae sp. nov.). From S. macleani , it is distinguished by having fewer midbody scale rows (27–31 in 94% of specimens versus 32–34 in S. macleani ). It differs from S. martinae sp. nov. by having fewer ventral scales (56–65 in 95% of specimens versus 68–71 in S. martinae sp. nov.) and by having fewer finger-IV + toe-IV lamellae (22–29 in 92%

of specimens versus 30–36 in 89% of specimens belonging to S. martinae sp. nov.). It differs from S. nitidus by having fewer finger-IV lamellae (9–12 in 89% of specimens versus 13–15 in 80% of specimens belonging to S. nitidus ). It is distinguished from S. powelli sp. nov. by having fewer midbody scale rows (27–31 in 94% of specimens versus 32–34 in S. powelli sp. nov.) and by having fewer dorsals + ventrals (113–124 in 85% of specimens versus 125–132 in 93% of specimens belonging to S. powelli sp. nov.). From S. semitaeniatus , it differs by having a lower number of midbody scale rows (27–30 in 92% of specimens belonging to S. caicosae sp. nov. versus 31–34 in S. semitaeniatus ). Additionally—and except for S. anegadae sp. nov., S. lineolatus , and S. powelli sp. nov. — S. caicosae sp. nov. is a smaller species than all others within Spondylurus (maximum adult SVL 77.6 mm versus 79.3–107 mm in other species).

Description of holotype ( Figs. 54B , 59A–B ). An adult male in excellent state of preservation, without injuries and with an abdominal slit. SVL 55.3 mm; tail length not measured; HL 9.86 mm; HW 6.98 mm; SW 1.84 mm; EL 1.03 mm; and toe-IV length 6.69 mm; ear-opening average in size and round; toe length in the following order: I <V <II <III <IV.

Head scalation. Rostral wider than high, contacting first supralabials, nasals and supranasals. Paired supranasals not in median contact, contacting anteriormost loreal. Frontonasal octagonal, wider than long, laterally in contact with anterior loreal scale. A pair of quadrilateral prefrontals, separated medially, and in contact with frontonasal, both anterior and posterior loreals, first supraciliary, first supraoculars, and frontal. Frontal heptagonal and elongate, in contact with the second supraoculars and paired frontoparietals. Frontoparietals also in contact with parietals and interparietal. Interparietal tetragonal and lanceolate, separated from nuchals by parietals; parietal eye distinct. Parietals in contact with upper secondary and tertiary temporal scales. Four supraoculars, the second one being the largest. Four supraciliaries, the second the longest. Nostril in posterior part of the nasal. A small postnasal, bordered by supranasal, anterior loreal and first supralabial. Anterior and posterior loreals squarish with posteromedial and posteroventral projections on latter. One upper preocular and two lower preoculars (one medial). Seven supralabials, the fifth being the widest and forming the lower border of the eyelid. Five moderately enlarged scales behind eye (four on the left) comprising the postoculars; similar to temporal scales but smaller. One primary temporal, two secondary temporals, and three tertiary temporals; all imbricate, smooth, cycloid, not distinctly delimited from the scales on the nape and the sides of the neck. Seven infralabials. Mental scale wider than long, posterior margin straight. Postmental scale and two pairs of chin shields in contact with anterior infralabials. First two pairs of chin shields in contact medially; third pair separated by a smaller cycloid scale.

Body and limb scalation. Two rows of nuchal scales, both paired. Other scales on nape similar to dorsals. On lateral sides of neck, scales slightly smaller. Dorsal scales cycloid, imbricate, smooth, 58 in a longitudinal row; ventrals similar to dorsals; 61 in a longitudinal row; 30 scales around midbody. No distinct boundaries between dorsals, laterals and ventrals. Scales on tail and limbs similar to dorsals, except smaller on limbs. Palmar and plantar regions with small tubercles, subequal in size and delimited by a surrounding region of flatter scales. Subdigital lamellae smooth, single, 11 under finger-IV and 16 under toe-IV. Four preanals larger than adjacent ventral scales. No enlarged median subcaudal scales on tail.

Pattern and coloration. Dorsal ground color medium brownish-gray with small and often triangular-shaped (pointed anteriorly) dark brown spots, distributed in thin lines on body and tail ( Fig. 55B ). Dark dorsolateral stripes present, narrow (1.38 mm), dark brown, extending from top of head to first third of body. Dark lateral stripes present, dark brown with whitish spots, extending from loreal region to first third of body and ending in 2–3 dark brown vertical bars or spots ( Fig. 55B ). Pale middorsal stripe present, wide (2.70 mm), brownish-gray, extending from tip of snout to first third of body. Pale dorsolateral stripes present, whitish, extending from tip of snout to first third of body. Pale lateral stripes whitish, extending from tip of snout to forelimbs. Forelimbs pale gray with large brown spots and mottling on dorsal surfaces and without pattern on ventral surfaces; hindlimbs slightly darker than ground color and with more subdued brown spotting on dorsal surfaces (than on forelimbs) and without pattern on ventral surfaces. Ventral surface of body without pattern. Palmar and plantar surfaces dark brown. No information on color in life of holotype is available.

Variation. In coloration and scalation, most specimens resembled the holotype ( Tables 4–5), despite being from a large number of different islands in the Caicos archipelago.

Distribution. The species is widely distributed throughout the Caicos Islands, Turks and Caicos ( Fig. 9C ).

Ecology and conservation. One of us (S.B.H.) encountered 3 individuals at Wades Green Plantation on North Caicos in August, 1999. One was under a rock, and the other two were fighting each other on a vertical rock wall. Habitat notes associated with the large KU series include the following observations: 0.3 m above ground on bluff, on the islands. However, current threats include rats and domestic mammals, agriculture, and increased development for tourism, which is reducing habitat quality and area ( Reynolds 2011).

Based on IUCN Redlist criteria ( IUCN 2011), we assess the conservation status of Spondylurus caicosae sp. nov. to be Vulnerable (VU A2ace). It faces a primary threat from predation by introduced mammals, including black rats, and a secondary threat from habitat alteration. Studies are needed to determine the health of the populations, and threats to the survival of the species.

Reproduction. Twenty-two females (61.8–76.4 mm SVL) contained 1–3 (mean = 2.2) developing young. All of those specimens were collected January–March.

Etymology. The species name ( caicosae ) is a feminine genitive singular noun referring to the distribution of the species in the Caicos Islands.

Remarks. The uniqueness of the skinks from the Caicos Islands has been hinted in earlier work. For example, Mayer and Lazell (2000) noted some pattern differences between skinks from those islands compared with those of the Puerto Rico region. Biogeographic connections between the Turks and Caicos fauna and that of the Puerto Rico region have been noted as well ( Thomas & Hedges 2007) and are consistent with the direction of water currents which would have carried animals on flotsam ( Hedges 1996b). Spondylurus caicosae sp. nov. has a smaller body size and wider dorsolateral stripes than S. turksae sp. nov., and the dark lateral stripes usually extend only one-third of the way to the hindlimbs. In these ways, S. turksae sp. nov. resembles S. nitidus more than S. caicosae sp. nov. Nonetheless, both species are small ( maximum SVL , 78–79 mm) compared to others in the genus, including S. nitidus (96 mm SVL), have proportionately short heads (average head lengths 15.9–16.3% SVL, versus 18.3% SVL in S. nitidus ), and low numbers of midbody scale rows (rarely> 30), suggesting a close relationship. Note added in proof: our DNA sequence analyses indicate a separate origin for S. turksae from the Puerto Rican Bank.

Figures

FIGURE 9. Map showing the distribution of mabuyine skinks occurring on islands in the central, southern, and western Caribbean region. See Fig. 1 for location of the islands. The islands and species are: (A) Jamaica (Spondylurus fulgidus; hollow circle = specimen not examined); (B) Hispaniola (Spondylurus haitiae sp. nov., circle; Mabuya hispaniolae sp. nov., triangle; Spondylurus lineolatus, squares); (C) Turks and Caicos Islands (Spondylurus caicosae sp. nov., circles; Spondylurus turksae sp. nov., triangles; hollow triangle is Cotton Cay record (see text); (D) Margarita (Copeoglossum margaritae sp. nov.); and (E) Roatán (Marisora roatanae sp. nov.).

FIGURE 54. Head scalation in species of the Genus Spondylurus (left, side view; right, dorsal view). (A) S. anegadae sp. nov. (UMMZ 80583, holotype); (B) S. caicosae sp. nov. (AMNH R-80126, holotype); (C) S. culebrae sp. nov. (UMMZ 73823,

FIGURE 55. Representative patterns in species of the Genus Spondylurus (top, dorsal view; bottom, side view). (A) S. anegadae sp. nov.; (B) S. caicosae sp. nov.; (C) S. culebrae sp. nov.; (D) S. fulgidus; (E) S. haitiae sp. nov.; (F) S. lineolatus; (G) S. macleani; (H) S. magnacruzae sp. nov.; (I) S. martinae sp. nov.; and (J) S. monae sp. nov.

FIGURE 59. Spondylurus caicosae sp. nov., from the Caicos Islands. (A–B) AMNH R-80126, holotype, Long Cay off South Caicos. (C) KU 242165, 0.8 km E Cockburn Harbor, South Caicos. (D) uncataloged, ca. 3 km W Kew, North Caicos (live individual photographed by S. B. Hedges, 16 August 1999). (E) fetus from KU 242153, 0.8 km E Cockburn Harbor, South Caicos.