Marisora roatanae, 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 : 132-135

publication ID	https://doi.org/ 10.11646/zootaxa.3288.1.1
persistent identifier	https://treatment.plazi.org/id/39191A7F-078A-FF7B-2DA9-EEAA7EDDFA43
treatment provided by	Felipe
scientific name	Marisora roatanae
status	sp. nov.

Treatment

Marisora roatanae sp. nov.

Roatán Skink

( Figs. 46C View FIGURE 46 , 47C View FIGURE 47 , 52)

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

Mabuya brachypodus — Taylor, 1956:308 (part).

Mabuya brachypoda — Webb, 1958:1311 (part).

Mabuya mabouya mabouya —Peters & Donoso-Barros, 1970:200 (part).

Mabuya mabouya — Wilson & Hahn, 1973:116 (part).

Mabuya unimarginata — Villa et al., 1988:54 (part).

Mabuya brachypoda — Campbell, 1998:167 (part).

Mabuya unimarginata — Lee, 1996:247 (part).

Mabuya unimarginata —Savage, 2002:503 (part).

Mabuya unimarginata — McCranie et al., 2005:114 (part).

Holotype. TCWC 21955 View Materials , an adult female from Jonesville, Isla de Roatán, Islas de la Bahía, Honduras, 3 m, collected on 11 April 1965 (collector unknown).

Paratype (n = 1). Isla de Roatán , Honduras. UTA R 55232, an adult male from Oak Ridge , Isla de Roatán, Islas de la Bahía , Honduras (collected by Gary Ferguson in 1979).

Other material. Isla de Roatán , Honduras. Uncataloged, Politilly Bight (east side) , Isla de Roatán, Islas de la Bahía , Honduras, collected on 16 November 2010 by Stesha Pasachnik (only images of this third specimen were available; no character data were taken) .

Diagnosis. Marisora roatanae sp. nov. is characterized by (1) maximum SVL in males, 74.7 mm; (2) maximum SVL in females, 90.2 mm; (3) snout width, 2.38–2.96% SVL; (4) head length, 15.7–19.0% SVL; (5) head width, 12.6–14.1% SVL; (6) ear length, 0.95–1.15% SVL; (7) toe-IV length, 8.39–10.5% SVL; (8) prefrontals, two; (9) supraoculars, four; (10) supraciliaries, four (67%), five (33%); (11) frontoparietals, two; (12) supralabial below the eye, five; (13) nuchal rows, one; (14) dorsals, 57–58; (15) ventrals, 65–67; (16) dorsals + ventrals, 122–125; (17) midbody scale rows, 32; (18) finger-IV lamellae, 13–15; (19) toe-IV lamellae, 15–18; (20) finger-IV + toe-IV lamellae, 28–33; (21) supranasal contact, Y; (22) prefrontal contact, N; (23) supraocular-1/ frontal contact, Y (33%), N (67%); (24) parietal contact, Y; (25) pale middorsal stripe, N; (26) dark dorsolateral stripe, N; (27) dark lateral stripe, Y; (28) pale lateral stripe, Y; and (29) palms and soles, dark ( Tables 3–5).

Marisora roatanae sp. nov. differs from all other species in the Genus Marisora in having a small supraciliary- 1 scale (1.04–1.29% SVL versus 1.35–2.00% in other species; Fig. 50A View FIGURE 50 ). It also differs from individual species in other characters. From M. alliacea , it differs in having shorter limbs (arm + leg length, 54.9–56.2% SVL versus 58.0–70.0%; Fig. 49 View FIGURE 49 ), more midbody scale rows (32 versus 26–29), more dorsals plus ventrals (122–125 versus 113–121), and no dark dorsolateral stripes (present in M. alliacea ). From M. unimarginata , it differs in having two pairs of chin shields in contact with infralabials (versus usually one pair). From M. magnacornae sp. nov., it differs in having short limbs (arm + leg length 54.9–56.2% SVL versus 62.3%; Fig. 49 View FIGURE 49 ), more midbody scale rows (32 versus 30), and more dorsals plus ventrals (122–125 versus 117 in M. magnacornae sp. nov.).

Marisora roatanae sp. nov. is most closely related to M. brachypoda ( Fig. 5 View FIGURE 5 ). From M. brachypoda , it differs in having more midbody scale rows (32 versus 28–30 in M. brachypoda ). One of the 36 M. brachypoda examined, from Guanacaste, Costa Rica (TCWC 80536), has 32 midbody scale rows, although this specimen from Guanacaste may represent an undescribed species (see Remarks for Marisora ) and therefore has been removed from summary counts for that species. Marisora roatanae sp. nov. also has small ear openings (0.95–1.15% SVL; both ears of both specimens) compared with M. brachypoda (1.22–2.18% SVL; Fig. 53). The holotype of M. roatanae sp. nov. also has unusually small eyelid windows (1.36–1.37% SVL versus 1.50–2.82% in other species of Marisora ), although the paratype has more normal eyelid windows (1.79–1.85% SVL). Specimens of M. brachypoda from neighboring islands of Utila and Guanaja have supraciliary-1 scales, midbody scale counts, and ear lengths typical of M. brachypoda .

Two recently collected, uncataloged, specimens of Marisora roatanae sp. nov. (James R. McCranie, personal communication) agree with the type and paratype in having> 30 midbody scale rows (one has 32 and the other has 31 or 32 midbody scale rows). That character separates M. roatanae sp. nov. from other Middle American species ( M. alliacea , M. brachypoda , and M. magnacornae sp. nov.), which have 26–30 midbody scale rows, except M. unimarginata from lower Middle America (28–32 rows) and a possible new species from Costa Rica with 32 rows (see Remarks for Marisora ).

In pattern Marisora roatanae sp. nov. has the basic elements of Marisora (wide, dark lateral stripe above a narrow, pale lateral stripe) but differs from other species of the genus in having a mostly unspotted, gray-brown dorsum in life. Base (dorsal zone) coloration, in life, in M. brachypoda and other species usually is tan, coppery brown, or reddish-brown with more spotting, and in some cases ( M. alliacea ), dorsolateral stripes. The pale ventrolateral stripes that extend onto the hindlimbs of M. roatanae sp. nov. ( Fig. 47C View FIGURE 47 ) are distinctive in the holotype (but not in the paratype) and absent in nearly all other preserved specimens of Marisora except some M. brachypoda from Honduras (TCWC 19211–12; CM 63581–87); in those cases they are less well-developed and do not extend onto the hindlimbs.

Description of holotype ( Figs. 46C View FIGURE 46 , 52A–D). An adult female in good state of preservation, without injuries and with an abdominal slit. SVL 90.2 mm; tail length 145.0 mm (complete); HL 14.2 mm; HW 11.4 mm; SW 2.15 mm; EL 1.43 mm; and toe-IV length 7.57 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 in median contact, contacting anteriormost loreal. Frontonasal decagonal, 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, 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 posterodorsal projection on latter. Three upper preoculars and two lower preoculars. Seven supralabials, the fifth being the widest and forming the lower border of the eyelid. Three 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 pair of chin shields in contact medially; second and third pairs separated by a smaller cycloid scale.

Body and limb scalation. One row of nuchal scales. 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; 67 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 15 under toe-IV. Preanal scales similar to ventrals. No enlarged median subcaudal scales on tail.

Pattern and coloration. In preservative: Dorsal ground color medium brown with relatively few dark brown spots, distributed in two dorsolateral zones on body, in discontinuous stripes on tail, and uniformly on limbs. Dark dorsolateral stripes absent. Dark lateral stripes present, dark brown, extending from loreal region past hindlimbs. Pale middorsal stripe absent. Pale dorsolateral stripes present between bands of dorsolateral dark spots and dark lateral stripes. Two pale ventrolateral stripes present, whitish, extending from below eye to last third of body (upper stripe continues past hindlimbs and lower stripe continues onto hindlimbs), each bordered below by a dark line. Forelimbs and hindlimbs with large dark spots. Ventral surface of body without pattern. Palmar and plantar surfaces dark brown. No information is available on color in life of the holotype.

Variation. The pattern elements in the paratype and in Specimen PB are similar to those in the holotype, typical of other species of the Genus Marisora , although that difference may not be significant. Different preservatives (e.g., formalin versus ethanol) tend to alter coloration in different ways, and therefore subtle differences in coloration among preserved specimens, and especially between preserved and unpreserved specimens, should be interpreted cautiously.

Distribution. The species is distributed on Isla de Roatán, Islas de la Bahía, Honduras ( Fig. 9E View FIGURE 9 ), located approximately 60 km from the north coast of Honduras. All three specimens are from a relatively small region in central Roatán.

Ecology and conservation. No published information is available. Ecological information on mabuyine skinks from Utila and Guanaja ( McCranie et al. 2005) pertains to Marisora brachypoda . Specimen PB was found recently killed on a road. Forest habitats on Roatán, in practice, are not protected, although some areas are designated as "protected" (S. Pasachnik, personal communication). Deforestation continues for agriculture and commercial development. Rats are present on the island. Besides the two museum specimens, two Roatán skinks were found in 2011 (James R. McCranie, personal communication) and another two (Specimen PB and another near Jonesville) were sighted during a long term field survey of iguanian lizards on Roatán (S. Pasachnik, personal communication). This suggests unnaturally low abundance compared with other island populations of skinks (e.g., Caicos Islands and Dominica) where the mongoose does not occur.

Based on IUCN Redlist criteria ( IUCN 2011), we consider the conservation status of M. roatanae sp. nov. to be Endangered (EN A2ace). It faces a primary threat from predation by introduced mammals, including black rats. Studies are needed to determine the health of the remaining populations, and threats to the survival of the species. Captive breeding programs should be considered.

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

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

Remarks. The short limbs and chin shield configuration of Marisora roatanae sp. nov., and its possession of ventrolateral stripes, agree more with M. brachypoda than M. unimarginata , suggesting that M. roatanae sp. nov. and M. brachypoda are closest relatives. Such a relationship is also consistent with geography. Marisora roatanae sp. nov. and Marisora brachypoda -3 from Honduras have a moderately low sequence divergence (0.8%; Fig. 6 View FIGURE 6 ) and their time of divergence is estimated to be 0.6 Ma ( Fig. 7 View FIGURE 7 ), similar to the divergence of a currently recognized species from the Virgin Islands ( Spondylurus macleani ) and its closest relatives, and between other diagnosable species in the Genus Spondylurus ( Figs. 5–7 View FIGURE 5 View FIGURE 6 View FIGURE 7 ). The lower sequence divergence of M. roatanae sp. nov. and M. brachypoda in Fig. 5 View FIGURE 5 , on the other hand, is artifactual because the two Honduras specimens of M. brachypoda (samples 2–3) lack some fast-evolving mitochondrial sequences (16S rRNA in both, cyt b in one).

Roatán is the largest of the Bay Islands of Honduras and has several other endemic reptiles (Barbour 1928; McCranie et al. 2005). Bathymetry maps indicate that the island is separated from mainland Honduras by deeper water than other Bay islands such as Utila, and hence it was probably isolated for a longer time when sea levels rose following Pleistocene glaciation events.