Herpetology Notes, volume 12: 1037-1050 (2019) (published online on 29 October 2019) Ontogeny and reproductive aspects of Chiasmocleis lacrimae (Anura, Microhylidae, Gastrophryninae) in an unspoiled Atlantic Forest area in the state of Rio de Janeiro, Brazil Laura Acerb Cordioli1, Vitor Sampaio Matias1, and Ana Maria Paulino Telles de Carvalho-e-Silva1,* Abstract. Herein we provide data on the reproductive biology of a population of Chiasmocleis lacrimae, including a description of its spawning and the tadpole morphology and ontogeny, from Rio das Pedras Reserve, municipality of Mangaratiba, state of Rio de Janeiro, Brazil. Males called around a temporary pond, 60 meters above sea level. The amplexus was axillary. Males and females differed in size, coloration, and in the presence and distribution of dermal spines. The egg clutch formed round-shaped sets that floated on the water surface, with jelly involving approximately 245 eggs. The development from egg to stage 46 took about 30 days. At stage 25, the tadpoles had on average 10.2 mm in total length and continued growing until stage 38, reaching the maximum size of 20.3 mm. At stage 29, the shape of the third and fifth toe could be observed, and at stage 33 the shape of the second and fourth toes became visible. Only at stage 41 nostril openings could be seen. At stage 42 forelimbs came out simultaneously. The froglets reached 6.9 mm on average, about 1/3 of the adult size (17.7 to 22.8 mm). Keywords. Tadpole, development, oviposition site, morphometric characteristics, nest, froglet Introduction is classified by Haddad and Prado (2005) as type 1, with eggs and exotrophic tadpoles in lentic water. The wide Species of the family Microhylidae exhibit various array of developmental strategies, egg-laying patterns levels of fossoriality, with some species living on the and morphological variation is distinct in this family leaf litter and others being actively fossorial (Menin (Vera-Candioti, 2006; Haddad et al., 2008; Forlani, et al. 2007). Their reclusive habits make their capture 2010). difficult, limiting our knowledge about this group The genus Chiasmocleis Méhely, 1904 is currently (Caramaschi and Jim, 1983). Morphological and composed of 36 species, distributed from Panama molecular data support the monophyly of this family and Tropical South America, north and east of the (Ford and Cannatella, 1993; Haas, 2003; Frost et Andes. Twenty-seven of these species are recognised al., 2006; Peloso et al., 2014), although poor data on as inhabitants of Brazil and 18 in the Atlantic Forest, microhylid development hampers further interpretations from the states of Alagoas to Santa Catarina (Frost, about their evolutionary history (Fabrezi et al., 2012). 2019). Chiasmocleis lacrimae Peloso, Sturaro, Forlani, Ontogenetic studies in anurans may then help clarify Gaucher, Motta, and Wheeler, 2014 is the valid name the phylogenetic relationships and taxonomic issues for Chiasmocleis carvalhoi Cruz, Caramaschi and of these animal groups (Costa and Carvalho-e-Silva, Izecksohn, 1997, described from the Horto Florestal de 2008). Many species of this family have a generalised Santa Cruz (currently named Floresta Nacional Mário reproductive mode (Duellman and Trueb, 1986), which Xavier), municipality of Seropédica (22.733651°S, 43.709219°W; 40 m a.s.l.), state of Rio de Janeiro. It is distributed in the lowland forests of the Brazilian states of Bahia, Espírito Santo, Rio de Janeiro and São Paulo (Frost, 2019). In spite of this wide distribution, this species is currently listed as “endangered” in the IUCN 1 Laboratório de Biossistemática de Anfíbios, Departamento de Zoologia, Universidade Federal do Estado do Rio de Janeiro Red List (Pimenta and Peixoto, 2004). – UNIRIO, 22290-24, Rio de Janeiro, RJ, Brasil. The reproductive modes of many species of * Corresponding author. E-mail: [email protected] Chiasmocleis are poorly known (Haddad and Hödl, 1038 Laura Acerb Cordioli et al. 1997). Carvalho-e-Silva et al. (2008) reported in a period of heavy rain that caused the formation of reproduction of C. carvalhoi (= C. lacrimae) from the the temporary pond on the second day (Fig. 1A). In municipality of Mangaratiba, state of Rio de Janeiro, the following years, tadpoles were observed during the Brazil. Wogel et al. (2004) described the external reproductive period. morphology of the tadpole of C. lacrimae from the The pond was made up of three parts separated by municipality of Rio das Ostras, state of Rio de Janeiro, large stones, however interconnected, with variations Brazil, without any comparisons with congeneric in depth from 15 to 78 cm. One of the parts had little species. In this study, we describe the egg-clutch, water exposure, being almost entirely covered by rocks tadpole and the ontogeny of C. lacrimae and provide that formed hiding places from which many individuals data on its reproductive biology. of Chiasmocleis lacrimae vocalised. In periods when the temporary pond remained full, i.e., September Materials and Methods 2006, the relative air humidity was on average 80%, air Our study took place at the Rio das Pedras Reserve temperature 25°C, and water temperature 21°C. (22.991389°S, 44.100278°W), municipality of In the laboratory, tadpoles were euthanised with an Mangaratiba, state of Rio de Janeiro, Brazil, from overdose of chloretone 10% and fixed and preserved September 2006 to March 2009. This area is part of the in formaldehyde 5%, and their stages were identified Parque Estadual Cunhambebe and therefore is currently according to Gosner (1960). Adults and froglets were protected by law. Observations were conducted on the euthanised in chloretone 25%, fixed in formaldehyde right bank of the river named Rio Grande, between two 10% and preserved in ethanol 70%. The description of bamboo clumps, 60 m a.s.l. colour on life of adults, froglets and tadpoles followed Reproduction was accompanied in greater detail by six the Naturalist’s Color Guide (Smithe, 1975). people in September 2006, during a four-day observation Tadpoles were measured with a vernier calliper to Figure 1. A) Temporary pond in the Rio das Pedras Reserve, Rio de Janeiro, Brazil. B) A couple of Chiasmocleis lacrimae in axillary amplexus (UNIRIO 2547, female, SVL= 22.67 mm; UNIRIO 2546, male, SVL= 17.44 mm). C) Egg clutch of C. lacrimae in the water. D) Tadpoles of C. lacrimae swimming in the aquarium. Ontogeny and reproductive aspects of Chiasmocleis lacrimae 1039 the nearest 0.01 mm. The development of tadpoles since we did not find adults near the nests the day after was analysed from stages 25 to 46, by determination spawning. of the following morphometric characters (Altig and In adults, the dorsal body in life is dark brown (Color McDiarmid, 1999): internostril distance (IND), distance 121, Vandyke Brown), with a pale longitudinal dorsal between eye and nostril (END), interocular distance midline (Color 92, Horn) or without this line but with (IOD), distance between eye and snout (ESD), eye spots of the same colour on the dorsal line (Color 92, diameter (ED), tail height (TH), body width (BW), Horn) and dark eyes (Color 119, Sepia). The ventral tail length (TAL), body length (BL) and total length body is lighter (Color 124, Buff) with few spots. The (TL). For adults and froglets we used the following lateral body is light brown (Color 23, Raw Umber) with measurements (Duellman, 1970): internostril distance several light spots (Color 92, Horn). (IND), distance between eye and snout (ES), diameter Adults show a variation in colour pattern: some of the eye (DE), interocular distance (IOD), distance individuals of the same population have a dorsal midline, between eye and nostril (EN), head width (HW), head a midline on the dorsal thigh and two lines in the ventral length (HL), humerus length (HUL), forearm length region forming a “V” shape, with a median line which (FAL), hand length (HAL), thigh length (TL), tibia runs through this “V” below the gular region, lighter length (TIL), tarsus length (TAL), foot length (FTL) and than the colour of the dorsum. In other individuals, snout-vent length (SVL). The material was deposited in median dorsal lines and ventral lines are absent, but the collection of the Laboratório de Biossistemática de there are small irregular light spots distributed all over Anfíbios of the Universidade Federal do Estado do Rio the body. de Janeiro – UNIRIO, Rio de Janeiro, Brazil, under the Females are larger than males in snout-vent length, vouchers: 684, 714, 735, 1346, 2601, 2644, 2704, 2843, with mean of 22.78 mm (SD = 0.44, range = 22.15– 2844, 3391, 3392 (tadpoles); 2659 (froglets); 1030, 23.20 mm, n = 5) whereas males measure in mean 1035, 2007, 2557, 2746 (adult males); 1034, 1037, 17.71 mm (SD = 0.75, range = 16.85–18.85 mm, n = 1476, 1655, 2547 (adult females). 5). All other measurements of females were greater than those of males (Table 1). As evidence of sexual Results dimorphism, the gular region of females had irregular Adults were found only during breeding activity, lighter spots (Color 26, Clay), while in males the gular under heavy rain and after it, from dusk to dawn region is darker (Color 121, Vandyke Brown), similar to accompanied by intense calling activity. At night, pairs the colour of the dorsum, without irregular lighter spots were observed in axillary amplexus (Fig. 1B), and the (Color 92, Horn; Fig. 2). Males have dermal spines reproductive success was determined in the following distributed throughout their body dorsally, on the head morning through observation of egg clutches (Fig. 1C). and thighs, on the fingers and toes (Fig. 3), and ventrally Individuals remained active only during the reproductive only on the abdominal region. Females have fewer and season, in a short period, only less than 12 hours. tiny dermal spines scattered in the inguinal region, The pond where we found the tadpoles was formed inner thighs and cloacal region.