Chiasmocleis avilapiresae, Peloso & Sturaro, 2008

Peloso, Pedro Luiz Vieira & Sturaro, Marcelo José, 2008, A new species of narrow-mouthed frog of the genus Chiasmocleis Méhelÿ 1904 (Anura, Microhylidae) from the Amazonian rainforest of Brazil, Zootaxa 1947, pp. 39-52 : 40-47

Chiasmocleis avilapiresae sp. nov.

Figs. 1–7; Table 1

Holotype. MPEG 23299 (field number MAR 979 ), an adult female, from Estação Científica do Programa Pró-Biodiversidade da Amazônia (PPBio), Floresta Nacional Caxiuanã , municipality of Portel, state of Pará, Brazil (~ 1 o 59’S, 51 o 39’W; represented by a star in Fig. 9), collected in a pitfall trap by M.A. Ribeiro-Jr and S.H. Abrantes on 27 March 2007.

Paratopotypes. MPEG 23300–06 , 23318 , seven adult females and one adult male respectively, collected by M.A. Ribeiro-Jr. and D.L. Arcoverde, on 26 January to 13 February 2007 ; MPEG 23307-17 , 23319-26 , 17 females and two males, collected by M.A. Ribeiro-Jr and S.H. Abrantes, on 16 March to 2 April 2007 . MPEG 23318 and 23324 are cleared and stained ; MPEG 23303 was dissected for myological studies .

Paratypes (numbers in parenthesis refer to localities in Fig. 9). INPA 17258-59 , two females, from (1) Reserva Extrativista do Baixo Juruá , Rio Juruá , Juruá, state of Amazonas, Brazil (~ 3º45’S, 66º05’W), collected by V. T. Carvalho, S. Novelle and L. Lopes, on 20–29 May 2006 ; MPEG 5169 , adult female, from (2) Porto Urucu , Amazonas, Brazil (~ 4 o 53’S, 65 o 20’W), collected by M.S. Hoogmoed and T.C. Ávila Pires, on 21 November 1989 ; INPA 14218 , 14224 , two females, from (3) Lago Ayapuã , Rio Purus , Beruri, Amazonas, Brazil (~ 4 o 24’S, 62 o 15’W), collected by F. Waldez, on 1-30 June 2005 ; USNM 266139–41 , three adult males, from (4) Cachoeira Nazaré , western bank of Rio Ji-Paranã, state of Rondônia, Brazil (~ 9 o 45’S, 61 o 55’W), collected by A.L. Gardner, on 18–23 November 1986 ; USNM 284500–01 , 565956 , one female and two males, respectively, from (5) Nova Brasília , Rondônia, Brazil (~ 11 o 09’S, 61 o 34’W) and USNM 565955 , female, from (6) Rio Morim , Nova Colina, Rondônia, Brazil (~ 10 o 50’S, 61 o 43’W); collected by P.E. Vanzolini , R.I. Crombie and C.M. de Carvalho, 2–8 November 1984 ; CFBH 5132-33 , an adult female and a juvenile respectively, from (7) Fazenda Jaburi , Espigão D’Oeste, Rondônia, Brazil (~ 11 o 36’S, 60 o 44’W), collected by P.S. Bernarde, on 2–14 April 2001 ; INPA 13102 , female, (8) Igarapé Estrema , Left bank of Rio Aripuanã , Aripuanã, Amazonas, Brazil (~ 6 o 17’S, 60 o 23’W), collected by the INPA Herpetology field expedition, on 3 May 2005 ; MNRJ 14231–80 respectively, 31 females, 13 males, five juveniles and one of undetermined sex, from (9) Aripuanã , state of Mato Grosso, Brazil (~ 10 o 10’S, 59 o 28’W), collected by U. Caramaschi and R. N. Feio, on 1–5 November, 2005 ; MPEG 18571–73 , 23287–98 , three adult females and 12 juveniles from (10) Acampamento base Sapopema , Parque Nacional da Amazônia , Itaituba, Para, Brazil (~ 04 o 40’S, 56 o 33’W), collected by M.S. Hoogmoed and H.S. Silva-Filho, on 26 January to 18 February 2005 ; MPEG 23280 , adult female, from (11) Tapuama , Rio Xingu , Altamira, Pará, Brazil (3 o 36’39’’S, 52 o 20’26’’W), collected by R. Bernardi and D. André, on 6 March 2008 ; MPEG 23277–79 , three adult females, from (12) Fazenda Caracol , Rio Xingu , Anapu, Pará, Brazil (3 o 27’10’’S, 51 o 40’31’’W) collected by A. Lima, F. Rodrigues, M.J. Sturaro, and P.L . V. Peloso , on 15 March 2008 ; MPEG 22787 , one adult female, from (13) Fazenda Riacho , Monte Verde , Portel, Pará, Brazil (~ 3 o 15’S, 50 o 19’W), collected by J.O. Gomes and T.C. Ávila-Pires on 23 March 2007 ; MPEG 23338 , one female, from (14) Barragem da Pêra , Serra dos Carajás, Parauapebas, Pará, Brazil (~ 6 o 04’S, 49 o 54’W), collected by E. Carvalho-Jr and J.A. Chaves on 27 January 2005 ; MPEG 23339-41 , three females, from (15) Noroeste II, Serra dos Carajás, Parauapebas, Pará, Brazil, (~ 6 o 04’S, 49 o 54’W), collected by E. Carvalho-Jr and J.A. Chaves on 1 November to 30 December 2005 .

Diagnosis. A member of Chiamocleis based on: (1) clavicle and procoracoid present; (2) clavicle reduced, not reaching the scapula, extending beyond medial part of coracoid; (3) procoracoid touching the coracoids; (4) palatines absent.

A large species for the genus; maximum SVL = 26.8 mm in males and 37.8 mm in females. Body ovoid and robust, head triangular, snout rounded in dorsal and lateral views, IOD about 2–3 times the IND. Four distinctive fingers and five toes present; all but first finger fringed in males, less fringed in females; fingers not webbed; finger I well developed with a distinct subarticular tubercle present between the proximal phalanges; distinct subarticular tubercles present on all fingers; toes fringed, less distinct in females; toes usually extensively webbed in males and only basally webbed in females (see Variation below). Males with dermal spines on fingers and toes; both sexes with dermal spines on dorsum and toes, more numerous and more developed in males. Males with many spines on anterior portion of chin. A light horizontal line on the posterior thigh is always present. Chiasmocleis avilapiresae is further characterized by having procoracoids and clavicles; clavicles do not reach the coracoids and they are entirely supported by the procoracoid cartilage; coracoids do not meet medially; procoracoids calcified near their contact with the coracoids; epicoracoids and anterior area of sternum slightly calcified. Eight procoelous presacral vertebrae present; sacral diapophyses expanded laterally; urostyle without lateral expansions; phalangeal formula of hands 2-2-3-3 and of foot 2-2-3-4-3.

Description of the holotype ( Figs. 2, 3). Body ovoid, robust; head short, triangular, snout short, wider than long, rounded in dorsal and lateral views; nostril not protuberant, directed anterolaterally; internarial distance slightly smaller than distance between eye and nostril and about the same as the eye diameter; canthus rostralis only slightly defined; loreal region oblique, slightly convex; eyes small, slightly protruding; interorbital area slightly concave, without cranial crests; occipital fold absent; postorbital fold present, tympanum not visible externally; upper jaw projecting beyond lower; lower lip with truncate, trilobed anterior margin; tongue large, ovoid, covering approximately ¾ of mouth floor, with free lateral and posterior borders; choanae small, rounded, widely separated, positioned anterolaterally, anterior to eye; vomerine teeth absent.

Arm and forearm slender, without tubercles or crests. Hand not webbed, fingers slightly fringed, fingers without dermal spines; finger I well developed, with a visible subarticular tubercle; relative finger length I<II<IV<III; finger tips with small disks, except in finger I. Subarticular tubercles well developed, nearly rounded; supranumerary tubercles absent; palmar tubercle large, divided into two parts, inner larger, rhomboid, outer smaller ovoid; thenar tubercle large, rounded, at base of finger II.

Legs short (combined THL, TBH and FL lengths 1.5 times the SVL), relatively robust; lacking tubercles; tibial and tarsal ridges absent; foot basally webbed, webbing formula I2 - –3II2 - –3 + III2 + –4 - IV4 + –2 + V; toes with well developed disks in all but first finger; fringes present on unwebbed portions of toes. Relative toe length I<II<V<III<IV; toes lack dermal spines; subarticular tubercles well developed; supranumerary tubercles absent; inner metatarsal tubercle present, oval, outer metatarsal tubercle absent.

Skin smooth with very few scattered dermal spines on dorsum, slightly more numerous around the cloacal region; absent ventrally and on members.

Measurements of the holotype (mm). SVL 34.9, HL 6.9, HW 9.6, ED 2.2, IOD 5.3, IND 2.3, END 2.7, THL 13.9, TBL 14.6, FL 22.4, 3FD 0.7, 4TD 1.1.

Color of the holotype in preservative. Dorsum uniformly greyish brown; arm olive brown; forearm dark brown at inner side and olive brown at outer side; fingers cream with dark spots; dorsal surfaces of thigh and tibia same color as dorsum; cloacal region and posterior surface of thigh dark brown with a transverse white line on each side above; throat cream with brown reticutation; belly cream with irregular brown spots; ventral surface of thigh cream with few dark brown spots; ventral surface of tibia cream with several dark brown spots. Color in life of the holotype is unavailable.

Variation. Measurements of the type specimens are given in Table 1. The species shows marked sexual dimorphism, with females being larger than males (Student’s t test for SVL; t= 9.894, df=89, p=0.000). Fingers slightly fringed in both sexes, fringes more developed in males; fingers with dermal spines in males, absent in females. Toes with dermal spines in males, lacking or very few spines in females. Males and females with dermal spines on body, spines in males more developed and more numerous, sometimes lacking in females. Males with many spines on anterior portion of chin ( Fig. 6), absent in females. Females may present several spines around the cloaca. Variation in male and female foot webbing formula are, respectively: I(1 + – 1 +)–(2 + –2 -)II(2–1 +)–(3 + –2 +)III(2 - –1 +)–(3 + –2)IV(4–2)–(2 - –1 +)V and I(2–2 -)–(3–3 +)II(2–2 -)–(4–3 +)III(3 - –2 -)–(4 + – 3 –)IV(4–4 +)–(3–2)V.

A mid-dorsal light stripe is present in about 20% of the individuals examined. The light horizontal stripe on the posterior portion of the thigh in invariably present in all specimens. Throat pattern varies from uniformly light to uniformly dark (generally in males); however, most specimens show a reticulated pattern of dark marks against a light background ( Fig. 7). Venter varies from light with almost no dark markings to having a few small scattered small brown to black dots and from having few large spots to showing a reticulated pattern, with dark markings against a light venter.

Variation of color in life; MPEG 18571 (field notes by M.S. Hoogmoed): Dorsum brown with indication of slightly lighter dorso-lateral bands. Forelimbs beige. Belly white, with large black spots at perimeter of belly and under thighs. Ventral side of shanks with black and white marbling. A narrow white line on posterior surface of thigh.

MPEG 23279 ( Fig. 1; our own field notes): Snout whitish. Dorsum greyish brown with scattered withe spots; dorsolateral region reddish. Forelimbs yellow. Hindlimbs marbled with red, brown and grey tones. Throat, belly and under surface of thigh cream with dark brown spots. A narrow horizontal white line on back of thighs.

MPEG 23287 (fieldnotes by M.S. Hoogmoed): Dorsum grey brown with small white spots, white spots also present on hind limbs. Forelimbs orange-yellow. A narrow white line on back of thighs.

Osteology. Description based on two cleared and stained specimens (one male, MPEG 23318; and one female, MPEG 23324). The skull of C. avilapiresae is slightly wider than long (about 1.1 times), with its widest point at the angle of the jaws. The nasals are not in contact medially, although very close; nasals are in contact or just overlap the frontoparietals posteriorly. Frontoparietals paired, not in contact medially, overlap posterolaterally with the prootic and posteriorly with the exoccipital. Maxilary arch incomplete, maxilla do not reach the quadratojugal, which is much reduced. Alary process of the premaxilla almost vertical. Vomer present, divided in an anterior and a posterior portion; posterior portion of the vomer apparently fused to the sphenetmoid. Palatines are absent.

Pectoral girdle with procoracoid cartilages and clavicles present; omosternum not present; sternum present, broad, with round posterior margin, mainly cartilaginous but it shows some degree of mineralization in the anterior portion ( Fig. 4). Coracoids do not touch or overlap medially; procoracoid in contact with coracoid. Clavicles slightly curved (MPEG 23324) to almost straight (MPEG 23318), entirely supported by procoracoid cartilage; clavicles not in contact laterally with coracoids, with which it forms an acute angle; clavicles broadly separated medially.

Eight presacral vertebrae, all procoelous ( Fig. 5). All presacrals with lateral processes; process more robust in presacrals II, III, and IV; processes projected anteriorly in Presacrals I, II, VII and VIII; projected posteriorly in presacrals III and IV, slightly posteriorly in presacral V; process in presacral VI is perpendicular to the vertebral column axis. Sacral diapophyses expanded laterally; urostyle without lateral projections.

Phalangeal formula in hands 2-2-3-3, and in foot 2-2-3-4-3 ( Fig. 5). Terminal phalanges knobbed, with irregularly expanded tips ( Fig. 5). Prepollical and prehallical elements present.

Etymology. The specific epithet honors Dr. Teresa C. S. de Ávila Pires, “T.C.”, professor and researcher at the Museu Paraense Emílio Goeldi. Teresa has worked to understand and protect the Amazonian herpetofauna for over 20 years, focusing mainly on the taxonomy, systematics and biogeography of lizards.

Distribution. Known from scattered localities in the Brazilian Amazon basin, south of the Solimões and Amazonas rivers, in the states of Amazonas, Mato Grosso, Pará, and Rondônia ( Fig. 9).

Natural history. R.I. Crombie’s fieldnotes note that specimens from Nova Colina and Nova Brasília, Rondônia, were collected in primary forest or in clearings/pastures. Specimens occurred near isolated pools in stream flood plain, always on the bank of ponds distant 0.5–1 m from water, under leaves or pieces of bark. Crombie’s notes do not mention calling activity.

Specimens from Anapu, Itaituba and from the type locality (Caxiuanã, Pará) were collected in pitfall traps inside primary forest. Other microhylids collected in the same areas were Chiasmocleis jimi , Ctenophryne geayi , and Hamptophryne boliviana . Chiasmocleis avilapiresae occurs in sympatry with C. bassleri in at least three localities (Espigão do Oeste, Rondônia; Aripuanã, Mato Grosso and Itaituba, Pará). In Caxiuanã several specimens of the new species were found in stomachs of Ceratophrys cornuta , and one specimen was regurgitated by a Leptodactylus paraensis (M.A. Ribeiro-Jr, personal communication). A gravid female from the type locality contained approximately 1920 eggs. Advertisement call and tadpoles are unknown.