Leposternon cerradensis, Ribeiro & Vaz-Silva & Santos-Jr, 2008

Ribeiro, Síria, Vaz-Silva, Wilian & Santos-Jr, Alfredo P., 2008, New pored Leposternon (Squamata, Amphisbaenia) from Brazilian Cerrado, Zootaxa 1930 (1), pp. 18-38 : 19-24

publication ID	https://doi.org/ 10.11646/zootaxa.1930.1.2
persistent identifier	https://treatment.plazi.org/id/03B43F53-FFC8-EC5A-FF77-C12FFE2FFE37
treatment provided by	Felipe
scientific name	Leposternon cerradensis
status	sp. nov.

Treatment

Leposternon cerradensis View in CoL sp. nov.

Leposternon sp. , Vaz-Silva et al., 2007:341.

Holotype. MZUSP 96347 View Materials ( Figures 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ), adult female, from the Espora Hydroelectric Power Plant reservoir (18º39’48.4”S; 51º52’17.9”W), municipality of Aporé, southwestern of Goiás state, Brazil, collected on 15 May 2006 by Tamanduá Mirim Team of faunal rescue. GoogleMaps

Paratypes. Five adult specimens, all of them were collected in the type locality during the biological monitoring studies of the Hydroelectric Power Plant Espora reservoir. Male specimens: CEPB 5377 (field number RE 025), 12 May 2002 ; and MNRJ 16111 View Materials (field number RE 734), 16 May 2006 . Female specimens: MZUSP 96348 View Materials (field number RE 7), 11 May 2006 ; MZUSP 98036 View Materials (field number RE 0040), 12 May 2006 ; and CEPB 5378 (field number RE 041B), 12 May 2006 .

Diagnosis. Leposternon cerradensis is a medium-sized amphisbaenian (largest specimen snout-vent length 385 mm) diagnosed by the following combination of characters (measurements in mm): one or two pairs of precloacal pores, 299–341 dorsal postpectoral half-annuli, 302–349 ventral postpectoral half-annuli, 13–15 tail annuli, 118–121 precloacal vertebrae, 32–37 dorsal segments in midbody half-annulus, 30–36 ventral segments in midbody half-annulus, two supralabials, two infralabials, four series of large plates in dorsal head shields posterior to rostronasal, pectoral shields mostly diamond-shaped, head length 2.6–3.2% snoutvent length, rostronasal length 20.4–23.1% head length, azygous width 30.8–41.9% head width, azygous length 40.1–51.4% head length, frontal length with 23.7–38.2% head length, and prefrontal length 37.2– 44.4% head length.

Comparison with congeneric species (characters of others species of Leposternon in parenthesis). Leposternon cerradensis can be distinguished from all congeners except L. kisteumacheri and L. polystegum , by having two–four precloacal pores (pores absents), and pectoral shields mostly diamond-shaped ( Figure 3 A View FIGURE 3 ) (irregularly shaped). Additionally, the new species differs from L. infraorbitale by the presence of two supralabials (three), 302–349 ventral postpectoral half-annuli (201–262), and 118–121 precloacal vertebrae (87–98). Leposternon cerradensis differs from L. microcephalum by the presence of 299–341 dorsal postpectoral half-annuli (202–297), 302–349 ventral postpectoral half-annuli (186–254), and 118–121 precloacal vertebrae (90–104). Leposternon cerradensis differs from L. octostegum by presence of two supralabials (one), two infralabials (one), 299–341 dorsal postpectoral half-annuli (353–398), 118–121 precloacal vertebrae (144), 30–36 ventral segments per half-annulus of midbody (27–28), five series of large plates in dorsal head shields (three), 13–15 tail annuli (11). Leposternon cerradensis differs from L. scutigerum by presence of prefrontals, azygous, frontals and parietals shields distinct (indistinct shields), 299–341 dorsal postpectoral halfannuli (259–295), 302–349 ventral postpectoral half-annuli (250–278), 32–37 dorsal segments per half-annulus of midbody (22–27), 30–36 ventral segments per half-annulus of midbody (25–29), and five series of large plates in dorsal cephalic shields (two). Leposternon cerradensis differs from L. wuchereri by the presence of 299–341 dorsal postpectoral half-annuli (235–261), 302–349 ventral postpectoral half-annuli (233–254), and 32–37 dorsal segments in midbody half-annulus (16–19).

The new species can be distinguished from other species with precloacal pores ( L. kisteumacheri and L. polystegum ) by having two infralabials (three), first infralabials fused with lateral malar (lateral malar not fused), anterior margin of mental wider than posterior margin (posterior margin of mental wider than anterior margin), azygous width 30.8–41.9% of head width (21.9–26.9% and 11–16.4%, respectively) ( Figure 4 A View FIGURE 4 ), and rostronasal length 20.4–23.1% of head length (24.0–28.7% and 29.3–33.5%, respectively) ( Figure 4 B View FIGURE 4 ). Furthermore, L. cerradensis differs from L. kisteumacheri by the presence of 299–341 dorsal postpectoral half-annuli (244–271), and 302–349 ventral postpectoral half-annuli (246–264). Additionally, L. cerradensis differs from L. polystegum by the presence of 30–36 ventral segments in midbody half-annulus (22–28), preocular shields absent (preocular present), azygous length 40.1–51.4% of head length (15.2–21.8%) ( Figure 5 A View FIGURE 5 ), frontal length 23.8–38.2% head length (42.4–51.6%) ( Figure 5 B View FIGURE 5 ), prefrontal length 37.2–44.4% head length (23.4–30.8%) ( Figure 5 C View FIGURE 5 ).

Description of holotype. An adult female with snout-vent length 316 mm and tail length 18.3 mm (5.5% of total length); midbody diameter 8.8 mm; tail diameter 8.2 mm; head length 8.6 mm (2.5% of total length); head anterior height 1.9 mm; head posterior height 6.5 mm; head anterior width 3.0 mm; head posterior width 7.1 mm.

Rostronasal shield almost as high (2.0 mm) as long (1.8 mm), 2.3 times wider than long, with nostril in ventral portion, in contact with the first supralabials laterally, and azygous and prefrontals posteriorly. Azygous 1.3 times longer than wide, in contact with the prefrontals laterally, and frontals posteriorly ( Figure 2 A View FIGURE 2 ). Prefrontals rectangular, 2.8 times longer than wide, in contact with the first supralabials and oculars laterally, and frontals and temporals posteriorly. Frontals quadrangular, 1.2 times winder than long, in contact at midline (suture length 2.0 mm), temporals laterally, and parietals posteriorly. Parietals rectangular, 1.9 times winder than long, in contact at midline (suture length 0.7 mm), and contacting temporals laterally and occipitals posteriorly. Two occipital shields, in contact with the first dorsal anterior half-annulus posteriorly. Temporals 1.34 times longer than wide, contacting oculars anteriorly and postoculars laterally. Supraocular shield absent. Oculars rectangular, 1.6 times longer than high, contacting first supralabial anteriorly, second supralabial laterally and postocular posteriorly ( Figure 2 B View FIGURE 2 ). Ocular 1.3 times the length and 1.2 times the height of postocular, which contacts the first postsupralabials laterally. Two supralabials, the first 2.3 times longer and 1.5 times higher than the second. Two postsupralabials, the first rectangular and the second squared-shaped, contacting the second infralabials posteriorly. Two infralabials, the first 1.8 times longer and 1.6 times wider than second, fused with lateral malars posteriorly, in contact with the mental anteriorly, and postmental, malars and postmalars laterally. Mental with anterior margin 1.3 times wider than posterior margin, contacting postmental posteriorly. Postmental 1.6 times longer than wide, in contact with the two malars laterally and postmalar row posteriorly. Two malars on each side of the postmental; the external larger than internal. One row of nine postmalars ( Figure 2 C View FIGURE 2 ). The majority of pectoral shields with diamond-shape, central shields largest and laterals gradually decreasing in size ( Figure 3 A View FIGURE 3 ). Lateral grooves dividing the body in dorsal and ventral portions; dorsal region divided by vertebral groove; lateral grooves absent on tail.

Fourteen dorsal anterior half-annuli; 301 dorsal postpectoral half-annuli plus five incomplete half-annuli; 309 ventral postpectoral half-annuli plus eight incomplete half-annuli; four lateral half-annuli; and 14 tail annuli. Thirty-four dorsal and 32 ventral segments in midbody half-annulus and 38 segments in fifth tail annulus. Anal flap semicircular with numerous irregular segments. One precloacal pore on each side of lateral edge of anal flap ( Figure 3 B View FIGURE 3 ).

Color in life (based in the series-type). Overall color pattern ranged from whitish to pinkish. Sometimes the dorsum presents irregularly distributed yellowish tones areas. The cephalic shields whitish from azygous to edge of parietal ( Figure 6 View FIGURE 6 ).

Color in preservative (based on the type-series). The coloration is light cream on dorsal and ventral region, except in anterior portion of body, which presents a brownish pattern, probably by the accumulation of blood in the musculature, pattern found in other Leposternon species (SR pers. obs.).

Variation. Meristic and morphometric variation of the paratypes are presented in Table 1. Some variation in the disposition and morphology of cephalic shields were observed, base on comparison with the holotype. The paratype MZUSP 96348 View Materials presents divided left prefrontal, resulting in a small supraocular shield; and two precloacal pores on right side of the cloaca. The paratype CEPB 5378 presents the frontal shields semi-fused with azygous. The paratype CEPB 5377 presents two small shields in anterior portion of azygous. The specimens CEPB 5377 and MZUSP 96348 View Materials present elongated frontals shields between parietals, which contact the occipitals posteriorly .

Etymology. The specific epithet “ cerradensis ” refers to the central Brazilian savannas ecoregion (in Central Brazil), where the new species was collected.

Geographic distribution and habitat. The type-series was collected during the flooding of the reservoir of Espora Hydroelectric Power Plant (18º39’48.4”S; 51º52’17.9”W), municipality of Aporé, southwestern Goiás state, Brazil ( Figure 7 View FIGURE 7 ). The new species was collected only during the flooding period (three months, between 11 May to 31 August 2006, 27 Km 2 of flooded area). The region is partially degraded presenting areas of pastures with exotic grasses ( Brachiaria spp. ) and soybean monoculture ( Glycine max L.). However, there are enclaves of natural Cerrado habitat, including deciduous dry forests, typical cerrado savannas (“Cer- rado típico” according to the terminology used by Ribeiro & Walter 1998), and a high heterogeneity of natural riparian vegetation where the new species was collected. Along the Corrente River the vegetation ranges from flooded or dry gallery forest to marshy grasslands (“ mata ciliar paludosa inundável”, “ mata ciliar seca” and “varjão”, respectively). Leposternon cerradensis is only known from the type-locality. According to species lists in Ribeiro et al. (2007) and Vaz-Silva et al. (2007), L. cerradensis is sympatric with the following amphisbaenians: Amphisbaena alba Linnaeus , Amphisbaena mertensi Strauch , Cercolophia roberti (Gans) and Leposternon infraorbitale .