Spondylurus sloanii (DAUDIN, 1803)
Can you confirm these amateur observations of Spondylurus sloanii?
|Higher Taxa||Scincidae, Mabuyinae, Scincoidea, Sauria, Squamata (lizards)|
|Common Names||Virgin Islands Bronze Skink|
|Synonym||Scincus sloanii DAUDIN 1803: 287|
Scincus sloanei — MERREM 1820: 70
Spondylurus sloanei — FITZINGER 1826: 23
Tiliqua sloanii — GRAY 1831: 70
Scincus richardi — COCTEAU 1837
Tiliqua richardi — GRAY 1838: 292
Tiliqua sloanii — GRAY 1838: 293
Eumeces sloanii — DUMÉRIL & BIBRON 1839: 639
Mabouya sloanei — GRAY 1845: 94
Mabuia cuprescens — COPE 1862: 186
E[uprepes] semitaeniatus — PETERS 1871: 400 (part).
Mabuya sloanii — BOCOURT 1879: 401 (part)
Mabuia sloanii — GARMAN 1887
Mabuia nitida — GARMAN 1887: 51 (part)
Mabuia sloanii — BOULENGER 1887: 193 (part)
Mabuia sloanii — MEERWARTH 1901: 37
Mabuya sloanii — STEJNEGER 1904: 608 (part)
Mabuya sloanii — BARBOUR 1914: 320 (part)
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)
Mabuya mabouia — BARBOUR 1937: 147 (part)
Mabuya sloanii — GRANT 1937: 517 (part)
Mabuya mabouya sloanei — SCHWARTZ & THOMAS 1975: 141 (part)
Mabuya mabouya sloanei — MACLEAN et al. 1977: 30–34 (part)
Mabuya mabouya sloanei — HEATWOLE et al. 1981: 34 (part)
Mabuya mabouya sloanii — BRYGOO 1985: 101 (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 — MIRALLES 2005: 49 (part)
Mabuya sloanii — HENDERSON & POWELL 2009: 293 (part)
Spondylurus sloanii — HEDGES & CONN 2012: 201
|Distribution||British Virgin Islands (Little Tobago, Norman Island, Peter Island, and Salt Island); U.S. Virgin Islands (St. Thomas and its islets of Capella Island, Little Buck Island, Little Saba Island, and Water Island)|
Type locality: not given; Duméril & Bibron, 1839:639 restricted the type locality to “Saint-Thomas”.
cuprescens: St. Thomas
|Types||Holotype: MNHN 554; Duméril & Bibron, 1839:639 redescribed the holotype of Scincus sloanii Daudin, collected by "Richard père" = Louis Claude Richard, probably in 1781–89. Holotype of cuprescens apparently lost|
|Diagnosis||Diagnosis. Spondylurus sloanii is characterized by (1) maximum SVL in males, 71.6 mm; (2) maximum SVL in females, 88.9 mm; (3) snout width, 2.10–3.11% SVL; (4) head length, 15.2–19.2% SVL; (5) head width, 11.8– 13.9% SVL; (6) ear length, 1.12–1.73% SVL; (7) toe-IV length, 8.05–11.2% SVL; (8) prefrontals, two (95%), four (5%); (9) supraoculars, three (2%), four (98%); (10) supraciliaries, three (5%), four (95%); (11) frontoparietals, two; (12) supralabial below the eye, five (18%), six (77%), seven (5%); (13) nuchal rows, one (15%), two (75%), three (10%); (14) dorsals, 59–64; (15) ventrals, 58–68; (16) dorsals + ventrals, 118–131; (17) midbody scale rows, 32–34; (18) finger-IV lamellae, 10–13; (19) toe-IV lamellae, 14–17; (20) finger-IV + toe-IV lamellae, 24–30; (21) supranasal contact, Y (95%), N (5%); (22) prefrontal contact, Y (33%), N (67%, although nearly all in near contact); (23) supraocular-1/frontal contact, Y (38%), N (62%); (24) parietal contact, Y (95%), N (5%); (25) pale middorsal stripe, Y; (26) dark dorsolateral stripe, Y; (27) dark lateral stripe, Y; (28) pale lateral stripe, N (or weak); and (29) palms and soles, pale (Tables 3–5).|
Spondylurus sloanii differs from S. caicosae sp. nov., S. fulgidus, S. haitiae sp. nov., S. macleani, S. magnacruzae sp. nov., S. martinae sp. nov., S. nitidus, S. powelli sp. nov., S. spilonotus, and S. turksae sp. nov. by having a narrower middorsal stripe (1.11–2.42% SVL versus 2.61–10.4% in those other species). It differs from all other species except S. anegadae sp. nov., S. culebrae sp. nov., S. lineolatus, S. monae sp. nov., S. monitae sp. nov., and S. semitaeniatus by having a higher dark dorsolateral stripe width/middorsal stripe width ratio (1.09–2.96 versus 0.115–0.916 in those other species; Fig. 79). Spondylurus sloanii is distinguished from S. lineolatus and S. turksae sp. nov. by having a higher number of midbody scale rows (32–34 versus 26–30 in those other species). From S. macleani, it differs by having distinct dark lateral stripes (versus dark lateral stripes barely evident or absent in S. macleani). It is separated from S. fulgidus by having a higher number of dorsals (59–64 versus 52–58). From S. haitiae sp. nov., it differs by having fewer ventral scales (58–68 versus 69–72 in S. haitiae sp. nov.). From S. monae sp. nov., it differs by having a taller rostral scale: rostral height/length 1.26–1.71 versus 0.84–1.01 in S. monae sp. nov. (Fig. 61). It is separated 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.; Fig. 73A, E) and in having a high frequency (95%) of supranasal contact (versus no contact in S. monitae sp. nov.). Additionally, S. sloanii is a larger species (maximum SVL 88.9 mm) than S. anegadae sp. nov., S. caicosae sp. nov., S. fulgidus, S. haitiae sp. nov., S. lineolatus, S. macleani, S. martinae sp. nov., S. monae sp. nov., S. powelli sp. nov., S. semitaeniatus, and S. turksae sp. nov. (maximum SVL 63.7–85.9 mm in those other species). Spondylurus sloanii differs from S. anegadae sp. nov., S. fulgidus, S. haitiae sp. nov., S. magnacruzae sp. nov., S. monae sp. nov., S. monitae sp. nov., S. spilonotus, and S. turksae sp. nov. by having fewer total lamellae (190–198 versus 202–238 in those other species), although sample sizes are lower for this character (Table 4).
Within the Genus Spondylurus, S. sloanii is separated from most species by having a high frequency (67%) of prefrontal contact or near contact (prefrontal separation within 0.3% SVL = ~0.2 mm). One-third of specimens (eight of 24) have contact between prefrontals, which is generally rare in Mabuyinae (6% overall). In other species of Spondylurus, prefrontal contact is common only in S. fulgidus (52%) and S. haitiae sp. nov. (50%); uncommon or rare in S. anegadae sp. nov. (3%), S. lineolatus (11%), S. martinae sp. nov. (11%), and S. powelli sp. nov. (25%); and not observed in S. caicosae sp. nov., S. culebrae sp. nov., S. macleani, S. magnacruzae sp. nov., S. monae sp. nov., S. monitae sp. nov., S. nitidus, S. semitaeniatus, S. spilonotus, and S. turksae sp. nov.
From its closest relative, S. culebrae sp. nov. (Fig. 55C), S. sloanii (Fig. 73E) is distinguished by having shorter dark dorsolateral stripes (tapering at or before forelimbs versus posterior to forelimbs), shorter dark lateral stripes (extending to midbody versus to hindlimbs), in having limbs with only small dark spots (boldly mottled or barred in S. culebrae sp. nov.), and in lacking a pale lateral stripe (present and distinct in S. culebrae sp. nov.). Also, it has fewer finger-IV + toe-IV lamellae (24–29 in 91% of S. sloanii, versus 30–34 in 81% of S. culebrae sp. nov.) and is a smaller species, with a mean of 70.8 mm SVL (19 adults) compared with S. culebrae sp. nov. (mean = 82.1 mm SVL, 45 adults).
The molecular phylogeny (Fig. 5) shows that Spondylurus sloanii is closer, genetically, to S. culebrae sp. nov., S. macleani, and S. monitae sp. nov. than it is to S. semitaeniatus, but the greatest confusion in identification will likely be with the latter species because the two (S. sloanii and S. semitaeniatus) appear superficially similar and occur in close proximity and sympatry in the Virgin Islands. The most reliable character in separating these two species is the width of the dark dorsolateral stripes compared with the pale middorsal stripe as measured at the forelimbs instead of the normal location for this measurement, at the ears (Fig. 80A). In both species, the dark dorsolateral stripes taper posteriorly until they eventually disappear. However, in S. sloanii, the dark dorsolateral stripes start tapering more quickly, before the forelimbs (e.g., compare pattern in Fig. 78E with that in Fig. 81F). The dark dorsolateral stripe/middorsal stripe ratio is 0.43–1.08 in S. sloanii and 1.25–2.68 in S. semitaeniatus. A second useful character in separating the two species, although not 100% diagnostic, is prefrontal separation, already noted above. More than two thirds of S. sloanii have contact between prefrontals, or are within 0.3% SVL of contact, versus all S. semitaeniatus with > 0.3% separation of prefrontals (Figure 80B). In other aspects of pattern, adult S. sloanii usually differ from S. semitaeniatus in having a pale middorsal stripe that is darker than the pale dorsolateral stripes (versus the same color as the dorsolateral stripes in S. semitaeniatus), a dorsum with dark- edged scales giving a braided appearance (versus lacking a braided appearance in S. semitaeniatus), and in lacking a pale lateral stripe, or having one that is barely evident (versus having a distinct pale lateral stripe in S. semitaeniatus). Both species have been described as bronze or coppery, and more observations are needed, but the color of living and preserved S. sloanii appears to be more bronze or coppery than that of S. semitaeniatus [HEDGES & CONN 2012].
|Comment||Synonymy: after HEDGES & CONN 2012: 201. Cocteau, 1837 was mentioned in Gray [1839:292] and in Duméril and Bibron [1839:639] but only two brief extracts were published by Cocteau [1837a,b]; apparently the full manuscript, with names, was never published. See also discussion in HEDGES & CONN 2012: 206. Pinto-Sánchez et al. 2015 synonymized culebrae, macleani, and monitae with Spondylurus sloani.|
Distribution: erroneously reported from Jamaica (Garman, 1887; following Gray 1845).
Conservation status: endangered (Adkins-Giese et al. 2014).
Type species: Scincus sloanii DAUDIN 1803: 287 is the type species of the genus Spondylurus FITZINGER 1826.
|Etymology||The species (sloanii) was named in honor of Sir Hans Sloane (1660–1753), a British physician who studied the natural history of the West Indies, describing a skink from Jamaica which Daudin (1803) believed to be the same species as the specimen he described from St. Thomas.|