Marisora aquilonaria, Mccranie & Matthews & Hedges, 2020

Mccranie, James R., Matthews, Amy J. & Hedges, S. Blair, 2020, A morphological and molecular revision of lizards of the genus Marisora Hedges & Conn (Squamata: Mabuyidae) from Central America and Mexico, with descriptions of four new species, Zootaxa 4763 (3), pp. 301-353 : 318-322

Marisora aquilonaria sp. nov.

Southern Sierra Madre Skink

Fig. 7A, B, C

Mabuia agilis : Gadow 1905:195 (in part).

Mabuya mabouya : Dunn 1936:537 (in part).

Mabuya mabouya mabouya : Dunn 1936:544 (in part); Gaige et al. 1937:11 (in part); Oliver 1937:15; Smith & Taylor 1950:156 (in part); Davis & Smith 1953:105; Flores-Villela et al. 1991:161.

Mabuya mabouya alliacea : Burger 1952:186 (in part); Duellman 1954:20; Peters 1954:15; Duellman 1958:16; Peters 1960:331; Flores-Villela et al. 1991:161.

Mabuya brachypoda : Webb 1958:1311 (in part); Davis & Dixon 1961:49; Duellman 1961:77; Flores-Villela et al. 1991:160.

Mabuya unimarginata : García-Vázquez et al. 2006:168; Miralles et al. 2009b:602 (tissue sample only); Miralles & Carranza 2010:861 (in part; tissue sample only); Macip-Rios et al. 2012:103.

Mabuya unimarginata complex: Miralles et al. 2009a:68 (in part; tissue sample only); Pinto-Sánchez et al. 2015:204 (in part; by implication only, no specimens examined).

Marisora brachypoda : Hedges & Conn 2012:24 (in part); Lara-Resendiz et al. 2017:226 (in part).

Holotype. FMNH 103565 , an adult male from Hacienda El Sabino , 30 km S of Uruapan, Michoacán, Mexico, 19°16’59.881”N, - 101°58’0.1117”W, 1050 m elevation, collected 21 July 1936, by Hobart M. Smith.

Paratypes (15). MEXICO— Michoacán: FMNH 103562, 103575, 103575, 104590, 104592, 104606, 117144, adult males, FMNH 103576, 117129–30, 117132–33, adult females, all from type locality; Colima: FMNH 1650, adult female, Manzanillo; FMNH 1673, adult male, Paso del Río; Guerrero: USNM 113639, adult female, Paso de Limonaro.

Referred specimens (42; all examined). Mexico— Michoacán: FMNH 103563, 103566, 103572, 104595, 104607–09, 117128, 117134–35, 117139–43, 117145–46, all from type locality; Colima: USNM 31528, “no further data;” Distrito Federal: USNM 12718, “ Mexico City ” (in error); Guerrero: USNM 113620–23, 113625–28, Agua del Obispo; KU 61838, 2.5 mi S of Almolonga; USNM 113629–38, Chilpancingo; Jalisco: KU 100514 –16, Cuitzmalá; Morelos: SMF 81239, Sierra de Huautla.

Diagnosis. Marisora aquilonaria sp. nov. is a relatively small, short-limbed species of the genus characterized (data from 8 males, 8 females in type series) by (1) maximum known SVL in males 68.6 mm; (2) maximum known SVL in females 75.2 mm; (3) SW 3.1–4.3% SVL in males, 2.8–3.9% in females; (4) HL 19.3–21.6% SVL in males, 16.3–20.9% in females; (5) HW 12.2–14.1% SVL in males, 10.5–12.7% in females; (6) EAL 1.6–2.5% SVL in males, 1.3–2.4% in females; (7) Toe IV length 8.4–10.4% SVL in males, 8.0–9.8% in females; (8) prefrontals one per side; (9) supraoculars four per side; (10) supraciliaries 4–5 per side, most often 5 (81.3%); (11) frontoparietals one per side; (12) usually fifth supralabial below orbit (80.0%), occasionally sixth below orbit (20.0%); (13) nuchal rows one per side; (14) dorsals 52–55 (54.3 ± 1.3) in males, 50–59 (54.6 ± 3.1) in females; (15) ventrals 55–62 (57.9 ± 2.0) in males, 55–60 (58.5 ± 1.8) in females; (16) dorsals + ventrals 110–117 (112.6 ± 3.4) in males, 105–120 (113.6 ± 5.0) in females; (17) scales around midbody usually 28 (87.5%), 27 in 12.5%; (18) Finger IV lamellae 12–15 (12.6 ± 1.1) per side in males, 10–15 (12.3 ± 1.4) in females; (19) Toe IV lamellae 14–15 (14.5 ± 0.5) per side in males, 13–15 (14.0 ± 0.8) in females; (20) Finger IV + Toe IV lamellae 26–29 (27.1 ± 1.0) per side in males, 25–30 (26.3 ± 1.6) in females; (21) supranasals usually in medial contact and preventing frontonasal-rostral contact (93.3%); (22) prefrontals not in contact; (23) supraocular 1-frontal contact almost always absent (87.5%), except contact made on both sides in 6.3%, and point contact made on one side in 6.3%; (24) parietals in contact posterior to interparietal; (25) pale middorsal stripe absent, but some have small dark brown dorsal spots; (26) thin, indistinct dark brown dorsolateral stripe usually absent, occasionally present above upper edge of an occasionally present, indistinct, thin, pale dorsolateral stripe; (27) dark brown lateral stripe present; (28) distinct white lateral stripe present; (29) palms and soles pale brown or cream; (30) total lamellae for five fingers 41–50 (45.0 ± 3.1) in males, 41–51 (43.9 ± 3.6) in females; (31) total lamellae for five toes 49–53 (50.3 ± 2.4) in males, 42–53 (49.9 ± 3.4) in females. In addition, this is a short-limbed species with combined FLL + HLL/ SVL 53.4–57.8% in males, 50.8–57.2% in females and has two chinshields contacting infralabials ( Table 3 ).

Marisora aquilonaria sp. nov. is a member of the M. alliacea Group of Middle American Marisora and forms a monophyletic clade ( Fig. 3 ). Marisora aquilonaria is a relatively small species as is M. syntoma sp. nov. (see next Description). Marisora aquilonaria can be distinguished from M. syntoma in having 5 supraciliaries per side in 81.3% (versus 4 supraciliaries per side in 96.7% in M. syntoma ) and having combined Finger IV and Toe IV lamellae per side of 26–29, x = 27.1 ± 1.0 in males and 25–30, x = 26.3 ± 1.6 in females (versus 22–26, x = 23.7 ± 1.4 combined Finger IV and Toe IV lamellae per side in males and 22–27, x = 24.1 ± 1.8 in females in M. syntoma ). Marisora aquilonaria is distinguished from all remaining Mexican and Central American Marisora species by being smaller with a maximum known SVL of 68.6 mm in males and 75.2 mm in females (versus 77.0 mm in males of M. urtica sp. nov. [female M. urtica unknown], 81.0 mm in males and 89.0 mm in females of M. brachypoda ), 80.9 mm in males and 92.5 mm in females of M. lineola , 76.1 mm in males and 90.2 mm in females of M. roatanae , 85.7 mm in males and 95.1 mm in females of M. magnacornae , 79.0 mm in males and 90.3 mm in females of M. alliacea , and 84.0 mm in males and 90.3 mm in females of M. unimarginta ). Marisora aquilonaria is further distinguished from M. urtica by lacking any indication of dark dorsal lines (versus those lines indicated in M. urtica and by having 5 supraciliaries per side in 81.3% (versus 4 superciliaries in M. urtica ). Marisora aquilonaria differs further from M. brachypoda by having a tiny fifth supraciliary scale present posteriorly in 81.3% (versus that small scale absent in 96.7% of M. brachypoda ). Marisora aquilonaria differs further from M. lineola by lacking distinct dark and pale dorsolateral stripes (versus dark brown dorsolateral stripe or dashes suggestive of stripes present and a pale brown dorsolateral stripe present in M. lineola ). Marisora aquilonaria differs further from M. roatanae by having fewer toe lamellae for five toes (49–53, x = 50.3 ± 2.4 in males and 42–53, x = 49.9 ± 3.4 in females versus 55–62, x = 60.3 ± 0.5 in males and 54–61, x = 59.0 ± 2.7 in females in M. roatanae . Marisora aquilonaria differs further from M. magnacornae and M. alliacea ) by having shorter limbs (FLL + HLL/SVL 53.4–57.8% in males and 50.8–57.2% in females versus 60.8–68.7% in males and 55.8–68.0% in females of M. magnacornae and 62.5–74.6% and 58.0–67.6%, respectively, in M. alliacea ). Marisora aquilonaria differs further from M. alliacea in having pale palms and soles (versus palms and soles dark in M. alliacea ). Marisora aquilonaria differs from the extralimital M. pergravis by having fewer ventrals (55–62 in both sexes combined versus 70–73 in M. pergravis ), fewer dorsals (50–59 versus 62–63 in M. pergravis ), and having a dark lateral stripe (versus that stripe absent in M. pergravis ). Marisora aquilonaria has been previously confused with M. unimarginata of the M. unimarginata group, but besides the size differences discussed above, also differs from M. unimarginata by having shorter limbs (FLL + HLL/SVL 53.4–57.8% in males and 50.8–57.2% in females versus 56.9–66.9% and 55.9–69.1%, respectively, in M. unimarginata ). Marisora aquilonaria is known to differ from the extralimital and poorly known M. berengerae (incomplete morphological data available only from the literature of the unsexed holotype) of the M. unimarginata group only from genetic data; furthermore a huge geographical hiatus inhabited by other species of Marisora occurs between those two species.

Description of the Holotype. An adult male ( Fig. 7A ) in a good state of preservation with a SVL of 68.6 mm; TAL 116 mm; HL 13.5 mm; HW 9.1 mm; SW 2.4 mm; EAL 1.5 mm; ear opening ovoid; Toe IV length 6.5 mm; toe lengths in descending order I<V<II<III<IV.

Head scalation. Rostral wider than high, contacting first supralabial, anterior nasal, and supranasals. Paired supranasals in median contact, contacting upper edge of anteriormost loreal, anterior and posterior nasals, and frontonasal. Frontonasal decagonal, wider than long, laterally in contact with anterior loreal. A pair of pentagonal prefrontals, separated medially, and in contact with frontonasal, anterior and posterior loreals, first supraciliary, first supraocular and point contact with second supraocular, and frontal. Frontal heptagonal, much longer than wide, in contact with second supraocular, frontonasal, and paired frontoparietals. Frontoparietals also in contact with supraoculars 2–4 and with parietals and interparietal. Interparietal tetragonal and lanceolate, separated from nuchals by parietals. Parietal eye visible externally. Parietals in contact with upper primary, secondary, and tertiary temporal scales. Four supraoculars per side, second one largest. Five supraciliaries, second longest, fifth tiny. Nostril in posterior part of nasal, forming part of nasal division. A small postnasal bordered by frontonasal, anterior loreal, and first and second supralabials. Anterior and posterior loreals squarish with posterodorsal projection on latter. One upper preocular and one lower preocular. Seven supralabials, sixth widest and located below orbit. Three to four small postoculars, considerably smaller than temporal scales. Three primary, two secondary, and two tertiary temporal scales. All temporal scales imbricate, smooth, cycloid, not distinctly delineated from dorsolateral nape scales and those laterally on neck. Seven and eight infralabials. Mental scale wider than long, posterior margin straight. Postmental and two pairs of chinshields in contact with infralabials. Paired chinshields separated medially by a slightly smaller, somewhat cycloid-shaped scale.

Body and limb scalation. One row of enlarged nuchal scale per side, in medial contact. Other scales on nape similar in size to dorsals. Lateral neck scales slightly smaller. Dorsal scales cycloid, imbricate, smooth, 55 in a longitudinal row. Axillary pit absent, but tiny scales present in that region. Ventral scales similar in size and shape to dorsals, 58 in a longitudinal row. Twenty-eight scales around midbody. No distinct boundaries between dorsals, laterals, and ventrals. Scales on base of tail and limbs similar in size to dorsals, except smaller on limbs. Palmar and plantar surfaces with small, slightly conical scales, subequal in size, and delineated by a surrounding region of slightly larger, flat scales. Subdigital lamellae smooth, single, 12 on Finger IV, 15 on Toe IV. Preanal scales slightly larger than ventrals. No enlarged median subcaudal scales.

Pattern and coloration in preservative. Dorsal ground color median brown with a few darker brown spots, especially on dorsolateral portion of body. Tail similar ground color as that of body, but lacking distinct darker markings. Pale middorsal stripe absent. Pale dorsolateral stripe absent. Dark brown lateral stripe (ca. 2 1/2 scales high) extending from posterior edge of orbit to level above hind limb insertion, that lateral stripe without paler brown scales. A single, relatively thin (ca. 2/3 scale row high), white lateral stripe present per side, extending from rostral to level of cloaca, not passing along upper edge of hind limb, passing across lower edge of ear opening. Lateral white stripe bordered below by a thin (3/4 scale high) dark brown line. Indistinct uniformly distributed dark brown spots present on dorsal surfaces of limbs. Ventral scales pale brown, with barely indicated slightly darker scale edges. Palmer and plantar surfaces cream, same color as adjacent undersides of limbs. Adjacent lamellae slightly darker brown.

Variation. Most adults from Guerrero and some from Michoacán have small to tiny dark brown dorsal spots ( Fig. 7C ; also see Remarks), whereas those from Colima and much of Michoacán mostly lack those spots. Variation in some other characters is shown in Table 3 .

Distribution. Marisora aquilonaria is known to occur on the Pacific versant of western Mexico from northern Nayarit to at least southeastern Guerrero and southern Puebla and Morelos ( Fig. 6 ). Its known elevational occurrence is from near sea level to 2000 m. The area where its geographical distribution ends is not known since we did not have genetic data for any population between southern Guerrero and just west of the Isthmus of Tehuantepec region of southeastern Oaxaca.

Ecology and conservation. Oliver (1937) reported Marisora aquilonaria was usually seen on rock walls in Colima. As usual in Marisora species, M. aquilonaria prefers open habitats where the large majority of its known localities lie. Duellman (1961) speculated that it probably occurs throughout the coastal region of Michoacán, but museum specimens examined for this study are reported from at least as high as 2000 m elevation. Duellman (1965b), in a fieldwork based biogeographic study in Michoacán, classified what we call M. aquilonaria as a lowland species (0–1050 m elevation) living in arid tropical forest and tropical semi-deciduous forest along the Pacific coast. Gadow (1905:218) wrote that this and the following described species were “fond of basking on shrubs and … even climbs trees, hiding under the bark.” No conservation studies have been published, but species of Marisora generally adapt well to human presence, even living inside human occupied houses (JRM pers. observ.). Thus, this species is almost certainly of little concern regarding its conservation status (although see comments in account of M. lineola regarding the susceptibility of mabuyid skinks to invasive predators).

Reproduction. Oliver (1937:15) reported that females from Colima collected in July contained “well-developed young.” Webb (1958:1312) reported a Michoacán female, also collected in July, contained “embryos.” Davis & Dixon (1961) reported collecting gravid females and recently born individuals in June and July in Guerrero, Mexico.

Etymology. The specific name aquilonaria is a Latin feminine adjective derived from aquilonaris, which means north, northern, northerly. The name is used in reference to this nominal form being the most northerly known species of Marisora .

Remarks. Recognition of M. aquilonaria as a species distinct from all other Middle American nominal forms was first recovered by the genetic results of Pinto-Sánchez (2015; all but the Guatemalan clade in their tree Cluster 2), by our genetic analysis ( Fig. 3 ), and by our morphological study. We were unable to locate voucher specimens for those used in our genetic analysis, based on the available data. Examination of morphological characters of specimens from nearby localities to those sequenced samples support the genetic results.

Our genetic results also contain two monophyletic subclades with the Colima and Michoacán sequences separated from the Guerrero and Morelos subclade. However, morphological characters to support separate nominal forms could not be found. These three subclades diverged 3–4 Ma ( Fig. 4 ), each strongly supported (100% bootstrap) as monophyletic. Given the high level of divergence, the subclades likely represent different species, but such discrimination will require further sampling and analysis.

Duellman (1961:77) corrected the locality data Webb (1958) had given for the large series of Marisora from

Michoacán, Mexico. The correct locality is “at El Sabino at an elevation of 1050 meters, 30 kilometers south of

Uruapan.” That locality is also the type locality for this species. Images of this species can be found in Lara-Resendiz et al. (2017) and Ramírez-Bautista (1994).

Figures

FIGURE 3A. Phylogenetic tree of the genus Marisora from a maximum-likelihood analysis of DNA sequences of three mitochondrial genes (12S rRNA, 16S rRNA, and cyt b) and three nuclear genes (NGFB, R35, and RAG2) in 140 individuals (4,029 bp). A scale bar (2% sequence divergence) is indicated below. The numbers at left of nodes are bootstrap support values. The tree is rooted with Mabuya dominicana. Species delimited using ABGD indicated by black vertical lines at right; samples with horizontal bars missing cytochrome b Figure continues on two pages.

FIGURE 4A. Timetree of Marisora using the most complete data, from two mitochondrial genes (12S rRNA, cyt B). Posterior probabilities for the Bayesian analysis are in red. Nodes show divergence times in millions of years (black, 2 decimal places) followed by uncorrected p-distances (cyt b only; black, precentages) on nodes separating species. A scale bar indicates time (1 million years, Ma). Figure continues on two pages.

FIGURE 6. Map showing the localities of the Marisora specimens examined for this study. The gray arrow points to island record for M. urtica. Two extralimital species are also indicated: M. berengerae (San Andres, purple arrow) and M. pergravis (Providencia, yellow arrow).

FIGURE 7. (A) Adult male holotype (FMNH 103565) of Marisora aquilonaria (Michoacán, Mexico) in preservative, SVL 68.6 mm; (B) Live M. aquilonaria from Playa Azul, Michoacán, Mexico, showing essentially unmarked dorsum; (C) Live M. aquilonaria from Puerto del Bálsamo, Guerrero, Mexico, showing small dark spots on dorsum; images B, C taken by Jonathan A. Campbell.