Spondylurus monae, 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 : 179-182

Spondylurus monae sp. nov.

Mona Skink

( Figs. 55J , 70B , 72 )

Mabuia sloanii — Boulenger, 1896:113 (part).

Mabuia sloanii — Meerwarth, 1901:37 (part).

Mabuya sloanii — Stejneger, 1904:608 (part).

Mabuya sloanii — Barbour, 1914:320 (part).

Mabuya sloanii — Schmidt, 1926:156 (part).

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

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

Mabuya semitaeniatus — Grant, 1931:217 (part).

Mabuya semitaeniatus — Grant, 1932a:162 (part).

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

Mabuya mabouya sloanii — Dunn, 1936:544 (part).

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

Mabuya sloanii — Grant, 1937:504 (part).

Mabuya mabouya sloanei — Schwartz & Thomas, 1975:141 (part).

Mabuya mabouya sloanei — MacLean et al., 1977:27 (part).

Mabuya mabouya sloani — Rivero, 1978:71 (part).

Mabuya mabouya sloanei — Heatwole et al., 1981:34 (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 mabouya sloani — Rivero, 1998:394 (part).

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

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

Holotype. UMMZ 73824 , from Mona Island , Puerto Rico, United States (no specific locality on Mona), collected in July 1931 by Chapman Grant.

Paratypes (n = 34). Mona Island , Puerto Rico (no specific locality unless indicated) . CAS 10581–82 , Harry A. Beatty, September 1944 ; CAS 14628, Chapman Grant (no additional collection information available) ; CM 23774– 76 , Harry A. Beatty, Sardinera, August 1944 ; MCZ R-36625–28, Chapman Grant, May–June 1931 ; RT 11933, beach woods behind Playa de Mujeres , 22–23 April 1994 ; UMMZ 73817–18 and 239529–32, Chapman Grant, May 1932 ; UMMZ 73825 and 239547, Chapman Grant, summer 1931 ; UMMZ 124819 , Harold Heatwole , on road between lighthouse and landing pier, 5 November 1960 ; UMMZ 239533–46 , Chapman Grant, July 1931 .

Material not examined (n = 3). Mona Island , Puerto Rico. ZMH R09302–04 , Mona Island (no specific locality), 16 May 1894, C. Bock .

Diagnosis. Spondylurus monae sp. nov. is characterized by (1) maximum SVL in males, 85.9 mm; (2) maximum SVL in females, 85.0 mm; unsexed holotype, 87.0 mm SVL; (3) snout width, 2.25–3.58% SVL; (4) head length, 16.1–20.0% SVL; (5) head width, 11.1–13.9% SVL; (6) ear length, 1.23–2.26% SVL; (7) toe-IV length, 8.09–10.4% SVL; (8) prefrontals, two; (9) supraoculars, three (3%), four (97%); (10) supraciliaries, three (3%), four (91%), five (6%); (11) frontoparietals, two; (12) supralabial below the eye, five (9%), six (91%); (13) nuchal rows, two (74%), three (26%); (14) dorsals, 56–65; (15) ventrals, 60–72; (16) dorsals + ventrals, 119–135; (17) midbody scale rows, 28–34; (18) finger-IV lamellae, 11–16; (19) toe-IV lamellae, 15–19; (20) finger-IV + toe- IV lamellae, 26–33; (21) supranasal contact, Y (60%), N (40%); (22) prefrontal contact, N; (23) supraocular-1/ frontal contact, Y (59%), N (41%); (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. monae sp. nov. is distinguished 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 higher dark dorsolateral stripe width/middorsal stripe width ratio (0.985–2.14 versus 0.115 –0.916 in those other species). It is distinguished from S. culebrae sp. nov., S. monitae sp. nov., S. nitidus , S. semitaeniatus , S. sloanii , and S. turksae sp. nov. by having a longer rostral scale ( Fig. 61 ). It differs from S. anegadae sp. nov., S. caicosae sp. nov., and S. macleani , by having dark lateral stripes nearly continuous to the hindlimbs (versus absent or only on anterior body 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 the presence of a distinct pale lateral stripe (versus no or faint pale lateral stripe in those other species). From S. haitiae sp. nov., it differs by having a larger ear (ear length 1.23–2.26% SVL versus 1.19% in S. haitiae sp. nov.). It differs from S. lineolatus by having a longer head (head length 16.1–20.0% 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 equal-sized and equally-spaced narrow stripes in S. lineolatus ). From S. monitae sp. nov., it is distinguished by having parallel (versus concave) dark dorsolateral stripes on the parietal scales. From S. anegadae sp. nov., it is larger ( maximum SVL 87.0 mm versus 70.4 mm SVL).

Spondylurus monae sp. nov. also differs from other species in slightly overlapping characters. It is distinguished from S. magnacruzae sp. nov. and S. spilonotus by having a lower number of midbody scale rows (28–33 in 91% of specimens versus 34 in those other species). From S. fulgidus , it differs by having a lower number of supraciliaries (3–4 in 94% of specimens versus five in S. fulgidus ). It is separated from S. martinae sp. nov. by having a longer head (head length 17.3–20.0% SVL in 83% of specimens versus 15.0–17.1% in S. martinae sp. nov.). It is separated from S. nitidus by having a shorter toe-IV (toe-IV length 8.09–10.0% SVL in 88% of specimens versus 10.1–12.7% SVL in 93% of specimens belonging to S. nitidus ). In coloration, individuals from Mona ( S. monae sp. nov.) have been described as being distinctly paler (in life) than those from Puerto Rico (= S. nitidus ) and having white dorsolateral lines instead of iridescent bluish lines ( Grant 1931; Rivero 1998). Also, S. monae sp. nov. tends to have triangular-shaped dark spots on the dorsum, whereas such spots are lacking in S. nitidus , as noted by Grant (1931).

Description of holotype ( Figs. 70B , 72A–C ). An adult (unsexed) in good state of preservation, without injuries and with an abdominal slit. SVL 87.0 mm; tail length 99.3 mm (regenerated); HL 14.2 mm; HW 10.4 mm; SW 2.60 mm; EL 1.77 mm; and toe-IV length 7.51 mm; ear-opening average in size and oval; toe length in the following order: I <II = V <III <IV.

Head scalation. Rostral wider than high, contacting first supralabials, nasals and supranasals. Paired supranasals not in median contact, 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 supraoculars, and frontal. Frontal heptagonal, lanceolate, in contact with the second supraoculars and paired frontoparietals. Frontoparietals also in contact with parietals and interparietal. Interparietal tetragonal, 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 rectangular with posteromedial projection on latter. One upper preocular 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. 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. Eight infralabials. Mental scale wider than long, posterior margin straight. Postmental scale and two pairs of 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. Two rows of nuchal scales, paired. Other scales on nape similar to dorsals. On lateral sides of neck, scales slightly smaller. Dorsal scales cycloid, imbricate, smooth, 61 in a longitudinal row; ventrals similar to dorsals; 70 in a longitudinal row; 32 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, 13 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 tan with small dark brown spots, uniformly distributed on body. Forelimbs with dark brown mottling and hindlimbs mostly unpatterned. Dark dorsolateral stripes present, wide (2.06 mm), dark brown, extending from tip of snout to first third of body. Dark lateral stripes present, dark brown, extending from loreal region to last third of body. Pale middorsal stripe present, narrow (1.87 mm), medium tan, extending from tip of snout to first third of body. Pale dorsolateral stripes present, pale gray, extending from tip of snout to first third of body. Pale lateral stripes present, whitish, extending from below ear to first third of body, bordered below by a narrow dark line of spots. Ventral surface of body without pattern. Palmar and plantar surfaces unpigmented. No information is available on color of the holotype in life.

Variation. In coloration and scalation, most specimens resembled the holotype ( Tables 4–5). The pale dorsolateral stripes have been described as being cream in life ( Rivero 1998).

Distribution. The species is distributed on Mona Island, 57 km 2 ( Fig. 10B ).

Ecology and conservation. The island is a roundish, raised limestone block, flat on top, and covered with mostly dry forest and cacti. It is designated as an ecological reserve by the government of Puerto Rico and has no permanent residents. It is maintained by Puerto Rico's Department of Natural Resources and managed on site by several park rangers.

Grant (1932a) made a general comment (for the Puerto Rico area) that the favorite hiding place of mabuyine skinks was in dense clumps of Opuntia cactus. Rivero (1998) noted that skinks on Mona are common in the Sardinera area where they can be seen "sunning on individual piles of coconut palm trash, apparently not more than one specimen per pile" (no date was given for this observation).

One current threat is from human disturbance. The island is being used by immigrants, especially Cubans (passing through Hispaniola), who use Mona and Monito as points of first contact on U.S. soil, in response to the U.S. government's Cuban Adjustment Act of 1966 and later revisions, now called the "wet feet/dry feet" policy. In 2010–2011, dozens of immigrants claimed Mona as home (primitive hotel) until they were rescued by the U.S. Coast Guard, as detailed in news reports. It is likely that some habitat has been disturbed, although this disturbance is probably more severe on Monito, which is much smaller and has far less habitat (see below). At the time of this writing, nothing is being done to prevent this from occurring, and it is not known how much disturbance is taking place or its effects on the biodiversity.

and feral cats can have a devastating effect on small lizards ( Iverson 1978; García et al. 2001). Many of the threats to the survival of the endemic Mona Iguana, Cyclura stejnegeri ( Wiewandt & Garcia 2011) , apply to the Mona Skink. The last dated collection of Spondylurus monae sp. nov. was 51 years ago, but one of us (SBH) has seen a recent photograph of a live individual from Mona.

Based on IUCN Redlist criteria ( IUCN 2011), we assess the conservation status of Spondylurus monae sp. nov. to be Endangered (EN A3c; B1ab(iii)+2ab(iii)). It faces a primary threat from predation by introduced mammals, including cats and black rats, and a secondary threat from habitat alteration (in part, as a result of destruction by feral mammals). Studies are needed to determine the health of any remaining populations, and threats to the survival of the species. Captive breeding programs should be considered.

Reproduction. Three females (71.4–82.3 mm SVL) contained 3 developing fetuses. The date of collection for those specimens was May 1932 and 22–23 April 1994.

Etymology. The species name ( monae ) is a feminine genitive singular noun referring to the distribution of the species on the island of Mona.

Remarks. Boulenger (1896) appears to have made the first reference to mabuyine skinks occurring on Mona Island. See Remarks under Spondylurus culebrae sp. nov. for discussion of the confusion during the first half of the 20th century surrounding the name S. semitaeniatus and its application to skinks from Mona and Culebra.

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 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 61. Graph of rostral height versus rostral length in seven species of the Genus Spondylurus.

FIGURE 70. Head scalation in species of the Genus Spondylurus (left, side view; right, dorsal view). (A) S. martinae sp. nov.

FIGURE 72. Spondylurus monae sp. nov., from Mona Island, Puerto Rico. (A–C) UMMZ 73824, holotype. (D) MCZ R- 36627, paratype. Both from Mona Island (no specific locality).