Bothrops oligobalius, Dal Vechio & Prates & Grazziotin & Graboski & Rodrigues, 2021

Dal Vechio, Francisco, Prates, Ivan, Grazziotin, Felipe G., Graboski, Roberta & Rodrigues, Miguel Trefaut, 2021, Molecular and phenotypic data reveal a new Amazonian species of pit vipers (Serpentes: Viperidae: Bothrops), Journal of Natural History 54 (37 - 38), pp. 2415-2437 : 2420-2428

publication ID	https://doi.org/ 10.1080/00222933.2020.1845835
persistent identifier	https://treatment.plazi.org/id/039787D4-FFEE-C80A-608E-FF07FE05E3CF
treatment provided by	Carolina
scientific name	Bothrops oligobalius
status	sp. nov.

Treatment

Bothrops oligobalius sp. nov.

( Figures 2–7 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 )

Bothrops neglecta, Amaral 1923: 100–102 ; in part;

Bothrops neglecta, Hoge & Lancini 1962: 16 ;

Bothrops brazili, Hoge 1962: 63 ;

Bothrops neglecta, Roze 1966: 286 ;

Bothrops brazili, Hoge et al. 1972: 231 ; in part;

Bothrops brazili , Cunha & Nascimento 1975: 12–17; in part;

Bothrops brazili, Gasc & Rodrigues 1980: 591 ;

Bothrops brazili, Chippaux 1986: 50 ;

Bothrops brazili, Campbell & Lamar 1989 ;

Bothrops brazili, Campbell & Lamar 2004 .

Bothrops brazili ‘northern clade’, Dal Vechio et al. 2020

Holotype

A male, MZUSP 23282 View Materials ( MTR 13844) collected by Miguel Trefaut Rodrigues and Antoine Fouquet on 22 April 2007, under a leaf of Cecropia sp. in terra firme (non-flooded) Amazonian lowland forests, at the LourenÇo municipality (00°41 ʹ 48.2”S, 57°42 ʹ 45.1”W), state of Amapá, Brazil ( Figure 3 View Figure 3 ). ZooBank ID number: 8E9124E2-94E6-434B-B086 -5043CE02893C GoogleMaps

Paratypes

Ten specimens: Brazil: MNRJ 10050–51 View Materials (females) from São Gabriel da Cachoeira municipality, state of Amazonas ; MPEG 3274 View Materials (female) from Almeirim municipality, state of Pará ; MZUSP 11719 View Materials (male) from Rio Maracá , Mazagão municipality, state of Amapá; Colombia: ICN 2155 View Materials (male) from Puerto Santander, Caquetá river, Araracuara , Amazonas ; ICN 10000 (female), ICN 10001–02 View Materials (male) from Puré river , Letícia, Amazonas ( Figure 5 View Figure 5 ); ICN 8176 View Materials (female) from Caparú , Taraira lake , Vaupés; ICN 10404 (female) from Mosiro Itajura biological research, Taraira lake , Vaupés .

Diagnosis

(1) A robust body species, SVL = 245–805 mm, (2) short tail, TL = 35–113 mm; (3) 23–27 dorsals on the first third of the body; (4) 23–25 dorsals at midbody; (5) 18–21 dorsals on the last third of the body; (6) 156–164 ventrals in females (median = 160) and 154–159 in males (median = 156); (7) anal scale not divided; (8) 42–48 paired subcaudals in females (median = 44.5) and 47–52 in males (median = 48.8); (9) 9–13 lateral trapezoidal marks in each side (median = 11,01 and 11,7 on the right and left side, respectively); (10) postorbital stripe absent or poorly marked; (11) eight supralabials; (12) 10–12 infralabials; (13) second supralabial fused to the prelacunal; (14) belly checkered; (15) absence of vertebral stripe.

Comparisons with other species

Comparisons for meristic and qualitative characters are presented in Table 1. Attributes from other species are presented in parenthesis. The new species can be promptly assigned to the jararacussu group due its morphological similarities with

trapezoidal marks; POS: posocular stripe; SC: subcaudals V: ventrals; VS: vertebral stripe.

B. brazili , with whom the new species shared its specific epithet for over 60 years. Like other members in the jararacussu group, the new species presents the second labial scale fused to the prelacunal (separate in the alternatus and neuwiedi groups), postorbital stripe absent or faint (present in the alternatus , neuwiedi , atrox and jararaca groups), dorsal skin of the head with homogeneous colouration (blotched or patterned in the alternatus and neuwiedi groups and generally in the atrox group as well), stout and cylindrical bodies and terrestrial habit (slender, laterally compressed and arboreal habit in the taeniatus group), reddish and greyish background skin colouration and reddish eye (greenish background colour in the taeniatus group, skin generally brownish in the atrox , jararaca , alternatus and neuwiedi groups), eight supralabials and lower number of ventrals (generally 7 supralabials and higher number of ventrals in atrox group). Assignment of B. oligobalius to the jararacussu group is further supported by our molecular approach ( Figure 1 View Figure 1 ).

Within the jararacussu species group, Bothrops oligobalius can be distinguished from B. jararacussu and B. pirajai by the absence or a faint postorbital stripe (present in both species), greyish and reddish background skin colouration (yellowish or brownish background with black trapezoidal marks in both species), reddish eye (yellowish or brownish in both species). The number of ventrals in B. oligobalius (156–164 in females, 154–159 in males) distinguishes it from B. muriciensis (151–155 in females, 148–150 in males) and B. jararacussu (170–186 in females, 166–181 in males) ( Table 1). The phylogenetic position of B. oligobalius sister to a clade assembling B. jararacussu , B. pirajai and B. muriciensis (which correspond to the Atlantic Forest lineage in the jararacussu group) is further supported by high genetic divergence and highly disjunct distributions ( Figure 1 View Figure 1 ).

Bothrops oligobalius is similar to B. brazili in background skin colouration and general external morphology features. However, the species can be promptly distinguished from B. brazili due to a smaller number of lateral trapezoidal marks (9–13; mean = 11.01 and 11.7 on the right and left side, respectively; in B. brazili , 13–21 mean = 17.1 and 16.3 on the right and left side, respectively) and absence of a vertebral stripe (present in B. brazili ) ( Table 1, Figures 2 View Figure 2 , Figures 3 View Figure 3 , Figures 5 View Figure 5 and Figures 8 View Figure 8 ). Moreover, the low number of ventrals (156–164 in females and 154–159 in males), and subcaudals 42–48 in females and 47–52 in males in B. oligobalius also distinguish it from B. brazili (ventrals 174–186 in females and 175–184 in males, and subcaudals 45–56 in females and 54–61 in males) ( Table 1). Molecular analysis recovered these two species as non-sister lineage, with pronounced genetic distances between them. Moreover, the new species occurs north of the Amazon River, while B. brazili is restricted to areas south of the river, with no reported sympatry ( Figures 6 View Figure 6 , Figures 8 View Figure 8 ).

Lastly, the new species is distinguished from B. sanctaecrucis , a poorly known member of the jararacussu group from Bolivia, by the lower number of ventrals and caudals (171–185 and 56–57 respectively in B. sanctaecrucis ), lower number of lateral trapezoidal marks (18–21), and greyish to reddish background skin colouration (brownish to yellowish).

Description of the holotype

Subadult male ( Figures 3 View Figure 3 , Figures 4 View Figure 4 ), preserved in ethanol with the left hemipenis prepared; SVL 594 mm; TL 95 mm (13.7% of total length); head length 32.1 mm; head width 20.7 mm; rostral 4.6 mm high; nasals divided; 2/1 prefoveals; 2/2 postfoveals; prelacunal fused with second supralabial in both sides of head (lacunolabial present); 1/ 1 preocular; 2/2 postoculars; 8/8 supralabials; 7/7 interoculabials; 5/5 circumorbitals; 10/11 infralabial; mental longer than broad, contacting the first two infralabials anteriorly (on each side); five gulars between the chin shield and the first ventral scale; 4/5 rows of gulars separating the first ventral scales from the infralabials; 2/1 canthals; 8 posterior intercanthals; 4 intersupraoculars; cephalic scales with no or weak keels; 25/24/19 dorsals; 159 ventrals; anal scale not divided; 48 divided subcaudals. Posterior cephalic scales longer than wide and strongly keeled; temporal scales keeled; internasals, canthals and supraoculars smooth. At midbody, eight rows of paravertebral scales between two adjacent lateral trapezoidal marks. In preservation, the background skin colouration of the holotype is greyish, with 12/11 brownish/greyish lateral trapezoidal marks lighter on the central part; marks usually meet on the dorsum. Dorsal skin of the head homogeneously greyish, without distinctive blotches. Ventral skin of the head light grey, with the centre of the scales cream and scale edges light grey; Postorbital stripe absent to faint. Tail greyish/ brownish dorsally with small dark brown lateral blotches; posterior part of tail dark brown; subcaudals speckled on anterior portion and brownish posteriorly. Venter irregularly speckled with cream and greyish; speckles reaching the middle of the subcaudal scales.

Hemipenial morphology

Hemipenis bilobed, bicalyculate, and bicapitate (with thinning towards the tip of the capitulum); sulcus spermaticus extending to the tip of each lobe ( Figure 7 View Figure 7 ). Large calcified spines present on the body of the hemipenis on the sulcate and asulcate faces, reaching the capitulum. On the asulcate face, region from the base of the hemipenis to the fork

smooth and without spines. Intrasulcar region with many ossified spines; sulcus spermaticus bordered by small calcyfied spines up to the calyce ( Figure 7 View Figure 7 ).

Variation

The type series is fairly homogeneous in colouration pattern and pholidosis. The specimen ICN10001 shows nine supralabials on the right side, probably as a result of split of the fifth supralabial into two. Chin colouration can vary from totally cream to presenting the central part of scales cream with a greyish border. One specimen (MZUSP 11719) shows 13 lateral trapezoidal marks on each side of the body; one (ICN8176) has 13 marks on the left side; all other specimens have less than 13 dorsal trapezoidal marks.

Distribution and natural history

The new species is known from areas north of the Amazon River in the Guiana Shield region extending into western Amazonia, an area that includes Brazil (states of Amapá, Roraima, and the northern parts of Pará and Amazonas), French Guiana, Surinam, Guyana, Venezuela and Colombia. Its currently known range limit to the west lies around the Putumayo River, although the species may also occur in the Putumayo-Napo interfluve. The new species presents stout body and terrestrial habit, being found mainly in terra firme (non-flooded) Amazonian lowland forests. The species has rarely been sampled in the várzea (flooded) forests.

Etymology

The specific name derives from the Greek oligos (few) and balios (spotted, dappled). The name is a reference to the smaller number of lateral trapezoidal marks on the body compared to Bothrops brazili , a name now restricted to the populations south of the Amazon River (see below).