Spondylurus lineolatus ( Noble & Hassler 1933 ) Hedges, S. Blair & Conn, Caitlin E., 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 : 164-166

Spondylurus lineolatus ( Noble & Hassler 1933) comb. nov.

Hispaniolan Ten-lined Skink

( Figs. 55F , 64B , 66 )

Mabuya lineolata — Noble & Hassler, 1933:16. Holotype: AMNH 42145 , female, from Monte Cristi, Dominican Republic, 8 January 1930, collected by W. G. Hassler.

Mabuya lineolata — Dunn, 1936:550.

Mabuya lineolata — Barbour, 1935:129.

Mabuya lineolata — Barbour, 1937:147.

Mabuya lineolata — Cochran, 1941:303.

Mabuya lineolata — Schwartz & Thomas, 1975:140.

Mabuya lineolata — MacLean et al., 1977:24.

Mabuya lineolata — Henderson & Schwartz, 1984:24.

Mabuya lineolata — Schwartz & Henderson, 1988:150.

Mabuya lineolata — Schwartz & Henderson, 1991:455.

Mabuya lineolata — Powell et al., 1996:82.

Mabuya lineolata — Henderson & Powell, 2009:292.

Material examined (n = 10). Dominican Republic. KU 242008, Albert Schwartz, Monte Cristi, Cana (23 km NW Mao), 30 October 1971 . Haiti. KU 242001–02 , Albert Schwartz, Artibonite, 5.6 km W ça Soleil , 10–12 July 1978 ; KU 242003–04 , Albert Schwartz, Artibonite, 10.6 km W ça Soleil , 21 July 1979 ; KU 242005 (5 August 1978) , KU

242006 (20 July 1979), KU 242007 (no date), Albert Schwartz , Artibonite, 1.9 km W Ennery, 333 m ; MCZ R- 156938, Albert Schwartz, Artibonite, 10.6 km W ça Soleil, 121 m, 11 July 1978 ; USNM 329347 , S. B. Hedges & R. Thomas, 10.4 km NW ça Soleil, Haiti, 130 m, 18 July 1985 .

Material not examined (n = 3). Dominican Republic. AMNH 42145 (holotype) , AMNH 57165–66 (paratypes), W. G. Hassler, Monte Cristi (near the bank of the Rio Yaque del Norte ), 8 January 1930 .

Diagnosis. Spondylurus lineolatus is characterized by (1) maximum SVL in males, not available; (2) maximum SVL in females, 63.7 mm; (3) snout width, 1.97–2.34% SVL; (4) head length, 12.9–14.4% SVL; (5) head width, 9.58–11.6% SVL; (6) ear length, 1.18–1.69% SVL; (7) toe-IV length, 7.23–9.16% SVL; (8) prefrontals, two; (9) supraoculars, four; (10) supraciliaries, three (63%), four (38%); (11) frontoparietals, two; (12) supralabial below the eye, four (11%), five (89%); (13) nuchal rows, one (44%), two (56%); (14) dorsals, 57–67; (15) ventrals, 59–67; (16) dorsals + ventrals, 116–134; (17) midbody scale rows, 26–28; (18) finger-IV lamellae, 8–11; (19) toe-IV lamellae, 11–16; (20) finger-IV + toe-IV lamellae, 21–26; (21) supranasal contact, Y (44%), N (56%); (22) prefrontal contact, Y (11%), N (89%); (23) supraocular-1/frontal contact, Y (11%), N (89%); (24) parietal contact, Y; (25) pale middorsal stripe, Y; (26) dark dorsolateral stripe, Y; (27) dark lateral stripe, Y; (28) pale lateral stripe, Y; and (29) palms and soles, dark ( Tables 3–5).

Spondylurus lineolatus differs from all other species in the Genus Spondylurus by having a smaller head (head length 12.9–14.4% SVL versus 15.0–21.6% SVL in other species) and by having 10 dark dorsal stripes (versus 2– 6 stripes).

Description of material. Five adult females, five juveniles in excellent state of preservation, without injuries and with an abdominal slit in each adult. SVL 34.9–63.7 mm; tail length 7.34–74.2 mm (broken or regenerated); HL 6.41–8.64 mm; HW 4.48–6.61 mm; SW 0.90–1.49 mm; EL 0.63–0.95 mm; and toe-IV length 3.36–5.26 mm; ear-openings average in size and round or oval; toe length in the following order: I <V <II <III <IV or I <II <V <III <IV.

Head scalation. Rostral wider than high, contacting first supralabials, nasals and supranasals. Paired supranasals in median contact or not, sometimes contacting anteriormost loreal. Frontonasal heptagonal and lanceolate, wider than long, laterally in contact with anterior loreal scale. A pair of quadrilateral prefrontals, separated or in contact medially, and in contact with frontonasal, both anterior and posterior loreals, first supraciliary (rarely), first (and sometimes second) supraoculars, and frontal. Frontal hexagonal or heptagonal, in contact with the second (and sometimes first) 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 longest and largest. Three or four supraciliaries, the first (where three are present) or second (where four are present) the longest. Nostril in posterior part of the nasal. A small postnasal, bordered by supranasal, anterior loreal, and first supralabial (and frontonasal, where supranasal-anterior loreal contact is absent). Anterior and posterior loreals squarish with posteromedial projection on latter, in some cases. One to three upper preoculars and two lower preoculars. Six to seven supralabials, the fourth or fifth being the widest and forming the lower border of the eyelid. Three to six moderately enlarged scales behind eye comprising the postoculars; similar to temporal scales. 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. Six or seven infralabials. Mental scale wider than long, posterior margin straight or curved toward tip of snout. Postmental scale and one or two pairs of adjoining chin shields in contact with anterior infralabials. First pair of chin shields in contact medially; second (and sometimes third) pair(s) separated by a smaller cycloid scale.

Body and limb scalation. One to two rows of paired or unpaired nuchal scales. Other scales on nape similar to dorsals. On lateral sides of neck, scales slightly smaller. Dorsal scales cycloid, imbricate, smooth, 57–67 in a longitudinal row; ventrals similar to dorsals; 59–67 in a longitudinal row; 26–28 scales around midbody. No distinct boundaries between dorsals, laterals and ventrals. Scales on tail and limbs similar to dorsals, except smaller on limbs. On regenerated portions of tails, one wide row of scales present on ventral surfaces. Palmar and plantar regions with small tubercles, subequal in size and delimited by a surrounding region of flatter scales. Subdigital lamellae smooth, single, 8–11 under finger-IV and 11–16 under toe-IV. Four to six preanals similar to ventrals or larger than adjacent ventral scales. Enlarged median subcaudal scales on regenerated portions of tails.

Pattern and coloration. Dorsal ground color pale to medium gray with 10 dark brown stripes extending from head to tail. Stripes cover dorsal and lateral body surfaces, the two (or, in some cases, four) most ventral stripes intersecting the axilla. Limbs also pale to medium gray with dark brown stripes. Ventral surface without pattern on

Color in life: Noble and Hassler (1933) described the coloration of the type series in life: "the dark stripes were nearly black while the light ones were lemon-yellow, changing into bluish at the tail-base. The tail was blue and the whole color pattern greatly resembled that of Ameiva lineolatus Duméril and Bibron. ”

Distribution. The species is distributed on Hispaniola, in northern Haiti and northwestern Dominican Republic ( Fig. 9B ).

Ecology and conservation. The ça Soleil localities are in a xeric coastal region receiving less than 75 cm of rainfall per year, whereas the other localities are somewhat more mesic (75–150 cm rainfall). Virtually nothing is known of the habits of this species except that specimens were found under objects on the ground. Remarkably, it has not been seen since 1985 despite the considerable herpetological survey work that has taken place on the island since then. As with declines in other species of mabuyine skinks in the late 19th and early 20th centuries, this species was almost certainly affected by the introduction of the mongoose. The persistence of Spondylurus lineolatus to (at least) the late 20th century, and of Mabuya hispaniolae sp. nov. to at least 1937, demonstrates that the introduction of the mongoose may not necessarily cause immediate extinction. However, neither species was ever commonly encountered, suggesting that their populations were negatively affected long before they were last observed. Shortly after S. lineolatus was discovered, Barbour (1937) noted, "it must be very rare to have eluded collectors for so long. The mongoose is abundant in San Domingo [= Hispaniola] to be sure, but the early collectors all failed to find the skink."

Deforestation is a continuing threat in Hispaniola. See comments regarding the estimation of forest cover, in Remarks for Spondylurus haitiae sp. nov. The primary forest of Haiti is likely <1% of total land area, and that of the Dominican Republic, ~5% of land area. There are national parks and other protected areas in Haiti and the Dominican Republic, but deforestation takes place within park boundaries, and therefore they do not afford complete protection, or sometimes, even partial protection.

Based on IUCN Redlist criteria ( IUCN 2011), we assess the conservation status of Spondylurus lineolatus to be Critically Endangered and possibly extinct (CR A2ace). It faces a primary threat from the introduced mongoose, which has possibly led to its extinction. Other major threats include habitat destruction from agriculture and charcoaling, and predation from other introduced mammals, including black rats. Studies are needed to determine if the species still exists, the health of any remaining populations, and threats to the survival of the species. Captive breeding programs should be undertaken, if the species still exists, because eradication of introduced mammalian predators is not possible on large islands. All mongoose-free islets of Hispaniola need to be thoroughly surveyed to determine if this species, or the other two species of mabuyines from Hispaniola, still exist.

Reproduction. Two females (56.2–63.7 mm SVL) each contained two young. The dates of collection for those specimens were 21 July 1979 and 5 August 1978.

Etymology. Not provided in the original description. However, the species name ( lineolatus ) is a feminine singular adjective derived from the Latin linea (line), hence lined, referring accurately to the lineate dorsal pattern of this species.

Remarks. The molecular phylogeny shows that Spondylurus lineolatus is a member of the Genus Spondylurus , which agrees with its multiple nuchal scales and distribution in the northern Caribbean. However, in pattern it differs strikingly from other species in the genus. As noted by Noble and Hassler (1933), it resembles, very closely, a sympatric and similarly pin-striped and blue-tailed species of teid lizard, Ameiva lineolata . The two species are virtually identical in body size and have blue tails as adults (blue tails are present only in juveniles of many other lizard species). Stripes are common in animal coloration, providing crypsis, and the consensus on blue tails in lizards is that they have an antipredator function, drawing attention away from the head ( Cooper 1985; Hawlena et al. 2006; Bateman & Fleming 2008). This is the most likely explanation for why these lizards resemble one another. If mimicry is involved, the likely mimic would be the skink because its pattern differs the most from its congeners. Also, Ameiva have proportionately larger heads than skinks and will bite at predators (at least fingers of collectors) fiercely. Thus S. lineolatus might gain a slight advantage by resembling Ameiva lineolata in an encounter with a small predator.

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 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 64. Head scalation in species of the Genus Spondylurus (left, side view; right, dorsal view). (A) S. haitiae sp. nov. (MCZ R-3617, holotype); (B) S. lineolatus (MCZ R-156938); (C) S. macleani (MCZ R-182270, paratype); and (D) S.

FIGURE 66. Spondylurus lineolatus, from Hispaniola. (A–B) MCZ R-156938, 10.6 km W Ca Soleil, Haiti. (C) USNM 329347, 10.4 km NW Ca Soleil, Haiti (live individual, photographed by S. B. Hedges, 18 July 1985).