Spondylurus spilonotus (Weigmann 1837) 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 : 207-211

Spondylurus spilonotus (Weigmann 1837) comb. nov.

Greater Virgin Islands Skink

( Figs. 73F , 76D , 82 )

Euprepes spilonotus — Wiegmann, 1837:135 (no locality, ex. coll. "Meyer"; but see Remarks).

Euprepes spilonotus —Peters, 1864:50 (lectotype clarified as ZMB 1240, same specimen as examined by Schneider [1801:182], for syntype of Scincus auratus ; originally from collection of Meyer; no paralectotypes).

Eupr[epes] spilonotus — Peters, 1871:400 ( Jamaica, in error).

Euprepes (Mabuia) spilonotus — Peters, 1876:708 (part).

Euprepes spilonotus — Gundlach, 1881:311 (part).

Mabuia sloanii — Boulenger, 1887:193 (part).

M[abuya] spilonotus — Stejneger, 1904:609–10 (listed incorrect accession number for lectotype; restriction to Jamaica, in error).

Mabuya sloanii — Barbour, 1914:355 (part).

Mabuya spilonota — Barbour, 1914:355 (restriction to Jamaica, in error).

Mabuya sloanii — Schmidt, 1928:121 (part).

Mabuya sloanii —Barbour, 1930:105 (part).

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

Mabuya mabouya sloanii — Dunn, 1936:544 (part; listed incorrect accession number for lectotype).

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

Mabuya sp. — Grant, 1937:512 (part).

Mabuya spilonotus — Grant, 1940:111 ( Jamaica, in error; listed incorrect accession number for lectotype).

Mabuya spilonotus — Murray, 1949:128 ( Jamaica, in error).

Mabuya spilonota — Cochran, 1961:126 ( Jamaica, in error).

Mabuya spilonota — Horton, 1973:85 ( Jamaica, in error).

Mabuya mabouya sloanei — Schwartz & Thomas, 1975:141 (part; listed incorrect accession number for lectotype).

Mabuya mabouya sloanei — MacLean et al., 1977:30 (part).

Mabuya mabouya sloanei — MacLean et al., 1977:32 (part).

Mabuya mabouya sloanei — Schwartz & Henderson, 1988:151 (part; listed incorrect accession number for lectotype).

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).

Material examined (n = 6). U.S. Virgin Islands. ZMB 1240 (lectotype; images examined), type-locality restricted here to St. Thomas or St. John, coll. 1779–1799 (see Remarks ) ; ZMH R 09299, A. H. Riise, St. Thomas , 1877; ZMUC-R 91–92, P. E. Benzon, "probably St. Croix" (considered here to be from St. Thomas or St. John; see

Remarks for Spondylurus magnacruzae sp. nov.), accessioned 4 September 1834; ZMUC-R 93–94, Professor A. S. Oersted, St. John, collected 1845–46 (see Remarks) and accessioned 27 June 1846.

Diagnosis. Spondylurus spilonotus is characterized by (1) maximum SVL in males, 91.7 mm; (2) maximum SVL in females, 106.5 mm; (3) snout width, 2.74–3.05% SVL; (4) head length, 15.4–18.5% SVL; (5) head width, 12.0–13.9% SVL; (6) ear length, 1.76–2.05% SVL; (7) toe-IV length, 7.30–10.5% SVL; (8) prefrontals, two; (9) supraoculars, four; (10) supraciliaries, four; (11) frontoparietals, two; (12) supralabial below the eye, six; (13) nuchal rows, two (67%), three (33%); (14) dorsals, 62–64; (15) ventrals, 63–68; (16) dorsals + ventrals, 125–132; (17) midbody scale rows, 34; (18) finger-IV lamellae, 13–15; (19) toe-IV lamellae, 16–18; (20) finger-IV + toe-IV lamellae, 29–33; (21) supranasal contact, N; (22) prefrontal contact, N; (23) supraocular-1/frontal contact, Y (17%), N (83%); (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, pale ( Tables 3–5).

Within the Genus Spondylurus , S. spilonotus is distinguished from S. anegadae sp. nov., S. culebrae sp. nov., S. haitiae sp. nov., S. macleani , S. martinae sp. nov., S. monae sp. nov., S. monitae sp. nov., S. semitaeniatus , and S. sloanii by having a lower dark dorsolateral stripe width/middorsal stripe width ratio (0.287 –0.464 versus 0.500– 3.79 in those other species; Fig. 79 ). It differs from S. anegadae sp. nov., S. caicosae sp. nov., S. fulgidus , S. haitiae sp. nov., S. lineolatus , S. nitidus , and S. turksae sp. nov. by having a higher number of midbody scale rows (34 versus 26–33 in those other species). It is separated from S. anegadae sp. nov., S. macleani , S. powelli sp. nov., S. sloanii and S. turksae sp. nov. by having a distinct pale lateral stripe (absent or barely evident in those species). From S. fulgidus , it differs by having a lower number of supraciliaries (four versus five in S. fulgidus ). It differs from S. lineolatus by having a larger head (head length 15.4–18.5% SVL versus 12.9–14.4% in S. lineolatus ) and four major dark stripes (lateral and dorsolateral) instead of 10 dark pin stripes. From S. monitae sp. nov., it differs by having a higher number of supralabials (supralabial six below the eye versus supralabial five in S. monitae sp. nov.) and in lacking the guitar-shaped dark dorsolateral stripe pattern as on the parietal scales of S. monitae sp. nov. It differs from S. monae sp. nov. by having a higher number of midbody scale rows (34 versus 28–33 in 91% of specimens belonging to S. monae sp. nov.). From S. anegadae sp. nov., it differs in lacking supranasal contact (versus contact in that species) and is much larger ( maximum SVL , 107 mm versus 70.4 mm in S. anegadae sp. nov.).

Spondylurus spilonotus most closely resembles S. magnacruzae sp. nov., which occurs (or occurred) on St. Croix. Both species reach 107 mm SVL in the relatively small samples available, making them the largest species in the Genus Spondylurus . They also have a similar general pattern consisting of narrow dark dorsolateral stripes in the anterior portion of the body. However, S. spilonotus has more dorsal body spots (52–99 versus 3–37), a shorter supraciliary-1 scale (supraciliary-1/supraciliary-2 length ratio 0.35–0.50 versus 0.52–0.69; Fig. 69A ), and a larger ear (ear length 1.76–2.05% SVL versus 1.49–1.72%; Fig. 69B ). Also, the stripe pattern of S. spilonotus appears faded and with more irregular edges to the stripes, compared with that of S. magnacruzae sp. nov. (bold stripes with straighter edges), features not obviously related to age of the specimens or differences in preservation.

Description of lectotype ( Fig . 82A–D). The following is from our examination of detailed images of ZMB 1240. Some measurements and characters are omitted because they could not be taken accurately from the photographs. An unsexed adult in good state of preservation, without injuries and without an abdominal slit. SVL ~ 70 mm; tail length (complete) ~ 110 mm; HL ~13.0 mm; ear-opening round; fingers and toes clawed.

Head scalation. Rostral wider than high, contacting first supralabials, nasals and supranasals. Paired supranasals not in full contact (close), contacting anteriormost loreal. Frontonasal diamond-shaped, 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 and second supraoculars, and frontal. Frontal heptagonal and lanceolate, in contact with the second supraoculars and paired frontoparietals. Frontoparietals also in contact with parietals and interparietal. Interparietal near-triangular, 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. Four supraciliaries, the second the longest. Nostril in posterior part of the nasal. Postnasal bordered by supranasal, anterior loreal and first supralabial. Anterior loreal rectangular and posterior loreal squarish with posteromedial projection on latter. Two upper preoculars and two lower preoculars. Eight supralabials, the sixth being the widest and forming the lower border of the eyelid. Five moderately enlarged scales behind eye comprising the postoculars; similar to temporal scales but smaller, except primary postocular similar in size to primary temporal. One primary temporal, two secondary temporals, and three tertiary temporals; all adjoining 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. Three rows of nuchal scales, two paired (three scales on left, two on right). Other scales on nape similar to dorsals. On lateral sides of neck, scales slightly smaller. Dorsal scales cycloid, imbricate, smooth, 62 in a longitudinal row; ventrals similar to dorsals; 64 in a longitudinal row. 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. Six preanals similar to ventrals. No enlarged median subcaudal scales on tail.

Pattern and coloration. Dorsal ground color pale gray-green with small dark brown spots distributed sparsely on head, body, limbs, and tail. Limbs darker than ground color and forelimbs with denser spotting. Dark dorsolateral stripes present, narrow, dark brown, extending from top of head to first third of body. Dark lateral stripes present, dark brown with paler spots increasing from the forelimbs to the hindlimbs, extending from loreal region to last third of body. Pale middorsal stripe present, wide, pale gray-green, extending from top of head to first third of body. Pale dorsolateral stripes present, whitish, extending from top of head to first third of body. Pale lateral stripes present, whitish, extending from below eye to last third of body, bordered below by a narrow dark line. Ventral surface of body without pattern. Palmar and plantar surfaces unpigmented. There is no information on color in life of the holotype.

Variation. In coloration, most specimens resembled the lectotype, except that the dorsal ground color varied from pale gray-green to darker green or brown, and some specimens had more dark brown dorsal spots than the holotype and shorter lateral stripes ( Table 5).

Distribution. This species is distributed in the U.S. Virgin Islands, on St. John (52 km 2) and St. Thomas (77 km 2) ( Fig. 10E ).

Ecology and conservation. This species reached 107 mm maximum SVL and was sympatric with Spondylurus semitaeniatus (83 mm, maximum SVL ) and S. sloanii (89 mm, maximum SVL ) on St. Thomas and probably with both species on St. John (no specimens of those two species have been collected on St. John, but they are presumed to have occurred there based on their distribution on surrounding islands ( Fig. 10E ). It is possible that S. spilonotus occurred in the British Virgin Islands as well. Unfortunately very little collecting was done on islands other than St. Thomas and St. Croix prior to the introduction of the mongoose in the late 19th century, so it could have been easily extirpated from many islands without any record.

Spondylurus spilonotus has not been seen since the last specimen was cataloged in 1877, despite considerable herpetological survey work throughout the Virgin Islands. The presence of the introduced mongoose on the two islands where S. spilonotus is known to have occurred (St. John and St. Thomas) explains the absence of the skink on those islands today. Black rats also occur throughout the region and may have preyed on this species. Habitat alteration from agriculture and urbanization, another threat to the species, is a continuing problem on these islands and their islets.

Based on IUCN Redlist criteria ( IUCN 2011), we assess the conservation status of Spondylurus spilonotus as Critically Endangered and possibly extinct (CR A2ace). It faces a primary threat from the introduced mongoose, which has probably led to its extinction. Secondary threats include habitat destruction from agriculture and urbanization, 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.

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

Etymology. Not provided in the original description. However, the species name ( spilonotus ) is a Latinized noun in the nominative singular derived from the Greek nouns spilos (spot, stain) and notos (the back), referring to the distinctly spotted dorsal pattern of this species. When combined with Mabuya (feminine) instead of Euprepes or Spondylurus (masculine), some authors ( Barbour 1914; Cochran 1961; Horton 1973) converted the gender of the species name to feminine, whereas others retained it as masculine. As it is a noun and not an adjective, it retains the original (masculine) spelling, regardless of the gender of the genus.

Remarks. Spondylurus spilonotus is another old species name ( Wiegmann 1837) that has had a confusing history ( Bauer et al. 2003). See also the Remarks for S. semitaeniatus , another species described by Wiegmann and with a similar history. Until now, the name has generally been considered a synonym of either Spondylurus sloanii or Mabuya mabouya . Euprepes spilonotus was described by Wiegmann (1837) based on two specimens that were Latin—that one of the two specimens (locality not known) came from the collection of "Meyer of Stettin" (Exemplum Musei Meyeriani Stettinensis), and the other was "allegedly from the West Indies." The characters mentioned by Wiegmann (1837) have no current diagnostic value—as is typical for almost all of the early named taxa reviewed herein—and therefore the loss of the second specimen meant that no collection locality could be tied with the name or surviving type (ZMB 1240). Nonetheless, our examination of that specimen and characters, through detailed images, indicates that it came from either St. Thomas or St. John (where other, similar, specimens have been collected). Therefore we fix the type-locality as St. Thomas or St. John and designate this specimen as the lectotype.

Wiegmann's (and Schneider's) "Meyer of Stettin" probably was Johann Carl Friedrich Meyer (1739–1811), a student of Linnaeus in college, pharmacist and chemist in his career, and member of "Gesellschaft Naturforschender Freunde zu Berlin " (Friends Natural History Society of Research in Berlin), an organization having close ties with ZMB. Marcus Elieser Bloch (1723–1799), the source of Euprepes semitaeniatus (ZMB 1238) , was a founding member of that society ( Paepke 1999). Thus we suspect that ZMB 1240 had the same origin as ZMB 1238, regardless of whether or not it went through the hands of Johann Meyer. In other words, it probably came from Bloch's source of material shipped from St. Croix to Copenhagen and acquired during 1779–1799. Both specimens were described by Wiegmann (1837) at the same time, have close accession numbers, and trace to the work of Schneider (1801).

During the last two centuries, this species name has had additional confusion. Peters (1864) correctly identified the type as ZMB 1240. Stejneger (1904), however, listed it incorrectly as ZMB 3785; it is unclear whether he actually examined a different specimen or just listed the number incorrectly. Dunn (1936) further altered the holotype accession number by transposing the last two digits, resulting in "ZMB 3758," which was repeated by later authors ( Grant 1940; Schwartz & Thomas 1975; Schwartz & Henderson 1988) and recently corrected ( Bauer et al. 2003). Also, for about a century (1871–1973), Spondylurus spilonotus was thought to be the name for the Jamaican Skink (herein called S. fulgidus Cope ), at least by some authors, and was treated either as endemic to Jamaica or a species with a wider range but also occurring on Jamaica. That error appears to have been started by Peters (1871) and was followed by Stejneger (1904), Barbour (1914), Grant (1940), Murray (1949), Cochran (1961), and Horton (1973). Superficially, S. fulgidus and S. spilonotus might be confused because they both have a wide middorsal pale (tan) stripe, but otherwise they differ in scalation and other characters. Possibly related to this confusion regarding skinks from Jamaica and the Virgin Islands is a specimen of S. fulgidus in the Hamburg collection (ZMH R09298), from 1877, with an incorrect locality: "St. Thomas."

The collector of the two specimens of S. spilonotus from St. John , " Professor A. S. Oersted," was almost certainly Professor Anders Sandoe Oersted (1816–1872). He was known to have collected animals in the Danish West Indies between 1845 and May, 1846 ( Millspaugh 1902), thus constraining the date of collection of these skinks .

Figures

FIGURE 10. Map showing the distribution of mabuyine skinks occurring on islands in the greater Puerto Rico region. See Figure 1 for location of the islands. The islands and species are: (A) Puerto Rico (Spondylurus nitidus); (B) Mona (Spondylurus monae sp. nov., squares) and Monito (Spondylurus monitae sp. nov., circle); (C) Desecheo (Spondylurus nitidus); (D) Vieques (Spondylurus nitidus, circle), Culebra (Spondylurus nitidus, circles; Spondylurus culebrae sp. nov., squares), Cayo Luis Peña and Cayo Norte (S. nitidus, circles); (E) most of the U.S. and British Virgin Islands (Spondylurus macleani, diamond; Spondylurus sloanii, squares; Spondylurus semitaeniatus, circles; Spondylurus spilonotus, triangles); (F) Anegada (Spondylurus anegadae sp. nov.); and (G) St. Croix and Green Cay (Capitellum parvicruzae sp. nov., circle; Spondylurus magnacruzae sp. nov.,

FIGURE 69. Graphs of two diagnostic characters distinguishing Spondylurus magnacruzae sp. nov. from S. spilonotus. (A) supraciliary-1 length versus supraciliary-2 length. (B) ear length versus SVL. The lectotype of S. spilonotus is indicated with an arrow.

FIGURE 73. Representative patterns in species of the Genus Spondylurus (top, dorsal view; bottom, side view). (A) S. monitae sp. nov.; (B) S. nitidus; (C) S. powelli sp. nov.; (D) S. semitaeniatus; (E) S. sloanii; (F) S. spilonotus; and (G) S. turksae sp. nov.

FIGURE 76. Head scalation in species of the Genus Spondylurus (left, side view; right, dorsal view). (A) S. powelli sp. nov. (MCZ R-74343, holotype); (B) S. semitaeniatus (UMMZ 80585); (C) S. sloanii (USNM 576305); and (D) S. spilonotus

FIGURE 79. Graph of pale middorsal stripe width versus dark dorsolateral stripe width in 16 species of the Genus Spondylurus.

FIGURE 82. Spondylurus spilonotus, from St. Thomas and St. John, U.S. Virgin Islands. (A–D) ZMB 1240, lectotype, restricted here to St. Thomas or St. John, U.S. Virgin Islands (no specific locality). Photographs courtesy of Mark-O. Rödel. (E)