Rhinella parecis, Ávila & Morais & Perez & Pansonato & Carvalho & Rojas & Gordo & Farias, 2020

Ávila, Robson Waldemar, Morais, Drausio Honorio, Perez, Renata, Pansonato, André, Carvalho, Vinicius Tadeu De, Rojas, Rommel R., Gordo, Marcelo & Farias, Izeni Pires, 2020, A new species of the Rhinella margaritifera (Laurenti 1768) species group (Anura Bufonidae) from southern Brazilian Amazonia, Zootaxa 4868 (3), pp. 368-388 : 378-381

Rhinella parecis sp. nov.

( Figs. 4–6 )

Holotype. UFMT-A 13716 (adult male) collected at Vilhena Municipality , Rondônia State, Brazil (12º42’54”S, 60º15’27” W; 560m a.s.l.), on October 10, 2007 by D.H. Morais ( Figure 4 ).

Paratypes. Eleven males, four females and two juveniles of undetermined sex: UFMT-A 13698 , and 13711 (adult males) and UFMT-A 13821 (juvenile) collected with the holotype. UFMT-A 7496 (adult male) collected at Santa Rita Farm , Alto Alegre do Parecis Municipality , Rondônia State, Brazil (12º07’41”S, 61º52’02” W; 370m a.s.l.), on December 12, 2007 by J.A.S. Rodrigues-Filho. MNRJ 84743 (adult male) collected at Parecis Municipality , Rondônia State, Brazil, on February 02, 2013 by F.B.S. Teles; G.B.B. Silva. UFMT-A 18706 , 18715 , and 18723 (adult males), UFMT-A 18718 , 18720 , 18729 , and 18735 (adult females) collected at Guaporé district, Chupinguaia Municipality, Rondônia State, Brazil (12º13’49”S, 60º43’40” W; 330m a.s.l.), on March 08, 2014 by R. W. Ávila; P.H.B. Dávila. MZUSP 148801–02 (adult males) and MZUSP 148803 (juvenile) collected at Comodoro Municipality, Mato Grosso State, Brazil (13º04’28”S, 59º40’08” W; 560m a.s.l.), on November 27–28, 2009 by biologists of JGP Consultoria Ambiental. MNRJ 85730 and 85740 (adult males) collected at Comodoro Municipality, Mato Grosso State, Brazil on February 9, 2013 by F.B.S. Teles; G.B.B. Silva .

Referred specimens. MTR 25661 (adult male) and MTR 25809 (juvenile) from Parque Nacional dos PacaásNovos, Campo Novo de Rondônia municipality, Rondônia state, Brazil .

Etymology. The specific name parecis , a noun in apposition, refers to the Chapada dos Parecis, a plateau occupying large portions of the Brazilian states of Mato Grosso and Rondônia, Brazil.

Diagnosis. Rhinella parecis sp. nov. is diagnosed by the following combination of characters: (1) snout-vent length range 40.7–53.5 mm in males and 44.9–54.8 mm in females; (2) snout rounded in dorsal view, acute with fleshy ridge extending to the tip of the snout in lateral view; (3) canthal and pre-orbital crests absent; (4) supra-orbital, parietal and supra-tympanic crests present and low; (5) dorsolateral row of tubercles present; (6) bony protrusion at the angle of jaws absent; (7) tympanum evident; (8) vertebral apophyses absent; (9) toes half-webbed.

Comparison. Among the species of the Rhinella margaritifera species group (characters in parenthesis), the absence of canthal and pre-orbital crests distinguish Rhinella parecis sp. nov. from R. alata , R. gildae , R. hoogmoedi , R. margaritifera , R. martyi , R. ocellata , R. paraguayensis , R. roqueana , R. scitula , R. sebbeni , R. sclerocephala , R. stanlaii and R. yunga (canthal and pre-orbital crests present). Rhinella parecis sp. nov. is distinguished from R. alata by larger snout-vent length (SVL), dorsolateral line of tubercles weak, and triangular paratoid glands (SVL 37.54–39.20 mm in males, 37.78–49.69 mm in females, marked dorsolateral line of tubercles and elongated paratoid glands). Rhinella parecis sp. nov. is differentiated from R. gildae by having smaller SVL, dorsolateral line of tubercles weak, absence of both vertebral apophyses and bony knobs at the angle of jaws (SVL 46.3–64.5 mm in males and 67.3–70.6 mm in females, dorsolateral line of conical tubercles well marked, vertebral apophyses present especially in females and a prominent bony protrusion at the angle of jaws present). From Rhinella hoogmoedi , R. parecis sp. nov. is differentiated by smaller size, dorsolateral line of tubercles weak and absence of bony protrusion at the angle of jaws (SVL 38.3–63.9 mm in males and 40.9–69.7 mm in females, dorsolateral line of pointed tubercles well marked and a rounded tubercle at the posterior corner of mouth present). From Rhinella margaritifera and R. roqueana the new species is distinguished by the absence of both vertebral apophyses and bony knobs at the angle of jaws and dorsolateral line of tubercles weak (vertebral apophyses and a bony protrusion at the angle of jaws present and spinose dorsolateral line of tubercles). Rhinella parecis sp. nov. is distinguished from R. martyi by smaller size, dorsolateral line of tubercles weak, absence of both vertebral apophyses and bony knobs at the angle of jaws (SVL 55.3 ± 5.8mm in males and 64.7 ± 3.4mm in females, dorsolateral line of tubercles well marked, vertebral apophyses present and protruding bony knob at the angle of jaws present). From Rhinella paraguayensis the new species is differentiated by the absence of bony knobs at the angle of jaws, less marked dorsolateral line of tubercles, and snout acute in lateral view (bony protrusion at the angle of jaws present, marked dorsolateral line of tubercles and snout rounded in lateral view). From Rhinella scitula , R. parecis sp. nov. is distinguished by larger size, dorsolateral line of tubercles weak, and absence of bony knobs at the angle of jaws (33.8–46.1 mm in males, 45.9–50.5 mm in females, marked dorsolateral line of tubercles and a bony protrusion at the angle of jaws). The absence of bony protrusions at the angle of jaws, slightly smaller size, and rounded snout in dorsal view differs the new species from R. sebbeni (bony protrusion present, SVL 48.5–59.7 mm in males and 54.7–66.7 mm in females, and mucronate snout in dorsal view). The new species can be separated from R. sclerocephala by toes half-webbed, smaller size, absence of bony protrusions at the angle of jaws, and dorsolateral line of tubercles weak (toes fully webbed, SVL 55.4–67.3mm in males, 68.5–77.4 mm in females, bony knobs in the angle of jaws present and marked dorsolateral line of tubercles). From R. stanlaii , the new species is differentiated by the rounded snout in dorsal view, smaller paratoid gland, and absence of bony protrusions at the angle of jaws (pointed snout in dorsal view, paratoid gland developed, bony knobs in the angle of jaws present). From R. yunga , the new species is distinguished by its smaller size, granulose dorsal skin and presence of vocal slits (SVL 57.5–59.5 mm in males, 53.5–65.5 mm in females, skin on dorsum smooth with scattered tubercles in males, vocal slits absent).

From the seven species of R. margaritifera group with low cranial crests, R. parecis sp. nov. is distinguished from R. acutirostris by rounded snout in dorsal view, absence of bony protrusions at the angle of jaws, and by the dorsolateral line of tubercles weak (snout pointed, presence of bony knobs at the angle of jaws, and marked dorsolateral line of tubercles). Rhinella parecis sp. nov. can be differentiated from R. dapsilis by smaller size, snout lacking a developed proboscis, and by the dorsolateral line of tubercles weak (SVL 52.1–56.2 mm in males, 66.4–79.8mm in females, proboscis well developed, and marked dorsolateral line of tubercles). Rhinella parecis sp. nov. is distinguishable from R. lescurei by the triangular paratoid gland, and larger size (elongated paratoid, SVL 34.6 ± 4.3 mm in males, 43.7 ± 0.8 mm in females). The absence of dorsal ocelli colour pattern and acute snout with fleshy ridge extending to the tip of the snout in lateral view differentiates R. parecis sp. nov. from R. ocellata (dorsal ocelli colour pattern present and rounded snout in lateral view). The larger size, distinct tympanum, granulose skin on the dorsum, and upper eyelid width significantly smaller (5.5–8.6% of SVL in males—Tukey Test p<0.001 and 7.1–8.5 % of SVL in females—Tukey Test p=0.032) distinguishes Rhinella parecis sp. nov. from R. castaneotica (SVL 32.4–40.4 mm in males, 34.8–41.6 mm in females, tympanum indistinct, smoother skin on dorsum and larger upper eyelid width: 6.5–11.7% of SVL in males and 8.1–10.9% of SVL in females). From R. magnussoni the new species differs by the rounded snout in dorsal view, absence of bony knobs, and significantly smaller internarial distance in females (4.2–4.6% of SVL—Tukey Test p=0.025) and significantly larger head length in males (28.7–37.5% of SVL—Tukey Test p=0.041) (snout pointed in dorsal view, presence of bony protrusion at the angle of jaws, larger internarial distance in females: 4.7–5.9% of SVL, and smaller head length in males: 30.6–34.5% of SVL). From R. proboscidea , R. parecis sp. nov. is promptly distinguished by the snout lacking a developed proboscis, granulose dorsal skin in males and significantly smaller tibia length in males 34.1–39.3% of SVL—Tukey Test p<0.001) (snout with a proboscis, smooth dorsal skin in males and larger tibia length in males: 37.5–42.5 % of SVL).

Description of the holotype. UFMT 13716, Adult male ( Figure 4 ). SVL 42.9 mm; head wider (16.5 mm) than long (15.2 mm) at the angle of jaws. Snout rounded in dorsal view, acute with fleshy ridge extending to tip of snout in lateral view. Cephalic crests weakly developed, only the supraorbital, parietal and supratympanic crests present; canthus rostralis without crests, concave; interorbital and internarial region flat, nostrils protuberant directed dorsolaterally; eye to nostril distance equal to eye diameter, larger than internarial distance; upper eyelid width about 80% of eye diameter. Tympanum distinct, large, almost rounded; its horizontal diameter representing 93% of the vertical diameter and equal to internarinal distance. Corner of mouth angular, without bony knobs at the lower angle of jaws. Vocal slits present, lateral to the tongue; choanae small, ovoid, lateral, widely separated; tongue free, not notched behind. Paratoid glands small, triangular. A dorsolateral line of small tubercles extends from the posterior border of the paratoid gland to the groin. Vertebral apophyses absent. Skin on dorsal and ventral surfaces granulose, with scattered conical tubercles. Small tubercles covering lips, eyelids, interorbital and loreal region. Forearms and forelimbs robust covered with small tubercles of the same size of those in the dorsum and scattered larger tubercles on the edges. Fingers free, with tips slightly enlarged; length of fingers 2<4<1<3. Lateral fringes with small conical tubercles present on fingers. Palmar tubercle oval, large, smooth; thenar tubercle oval, about one third of the palmar tubercle; subarticular and supranumerary tubercles present, rounded. Hindlimbs robust, thigh length larger than tibia length, thigh+tibia length approximately 80% of the SVL; foot length 91% of tibia length, tarsal length 72% of foot length. Inner metatarsal tubercle oval, two times larger than the outer metatarsal tubercle; subarticular and supernumerary tubercles present, small, round. Length of toes 1<2<3<5<4; toes half-webbed, webbing formula: I 1-2 II 1-2 ½ III 1-3 IV 3-1V. Lateral fringes with small conical tubercles present on toes.

Measurement of the holotype (mm). SVL 42.9; HL 15.2; HW 16.5; IND 2.6; END 4.3; ED 4.2; UEW 3.4; IOD 6.6; POCH 1.0; POCL 4.9 ; HTD 2.6; VTD 2.8; PGL 5.2 ; HAL 11; FAL 12; THL 18.8; TL 15.8; TAL 10.4; FL 14.4 .

Colour in life. Dorsum light brown, with dark brown bands on arms and legs and dark brown blotches on flanks and tympanic region ( Figure 5a ). A gray vertebral line from the interorbital region to cloaca, surrounded by dark brown bands and black spots at midbody. Venter light brown with scattered dark brown blotches. Loreal and tympanic region with dark brown blotches. Throat dark brown, arms and legs with dark brown bands. Iris gold, with black reticulations.

Colour in preservative. Similar to that in life, although slightly faded mainly in dark brown blotches ( Figure 4 ).

Tadpole. Unknown.

Variation among paratypes. The type series includes 17 specimens (11 adult males, 4 adult females and 2 juveniles). Females are slightly larger than males and a summary of variation in measurements between sexes can be found in Table 3. Low cranial crests in both sexes, without differences between males and females. Dorsal skin texture not variable between sexes, being covered with scattered conical tubercles in males and females. Dorsal coloration is variable, from dark brown to cream ( Figure 6 ), sometimes with dark brown spots in midbody. Vertebral line is present in about 60% of the individuals. Ventral coloration is also variable from almost immaculate light brown to heavily pigmented with dark brown blotches. Males may present gular and chest brown coloration with a cream midventral stripe.

Geographic distribution. Rhinella parecis sp. nov. is known from seven localities from Mato Grosso and Rondônia states, western Brazil ( Figure 7 ). The species is also known from the Pacaás-Novos National Park . Most of these localities are in the Chapada dos Parecis (~ 650m a.s.l.), which separate the Paraguay and Amazon basins and present transition zones between Cerrado and Amazonia domains. Individuals of Rhinella parecis sp. nov. were found inside rainforest fragments, since several areas in this region have been deforested and transformed for cattle ranching and agricultural farming.

Figures

FIGURE 4. Holotype of Rhinella parecis sp. nov. (UFMT-A13716):Above—Dorsal and Ventral views; Below -Head in lateral view, right hand and right foot in ventral view. Scale bars = 10mm.

FIGURE 5. Adult specimens of Rhinella parecis sp. nov. in life. A) Holotype, adult male (UFMT-A 13716); B) Adult male (UFMT-A 13698); C) Adult female (UFMT-A 18718); D) Adult male (UFMT-A 18735). Photos by D. H. Morais (A, B) and R. W. Ávila (C, D).

FIGURE 6. Dorsal (above) and ventral (below) variation in the type-series of Rhinella parecis sp. nov. Scale bar = 10mm.

FIGURE 7. Distribution map of Rhinella parecis sp. nov. in the Brazilian states of Mato Grosso and Rondônia (left) with location in South America (right). Star represents the type locality and circles represent other collecting sites.