Reproductive features of Chaltenobatrachus grandisonae (Anura: Batrachylidae) within a protected area in Patagonia, Chile Características reproductivas de Chaltenobatrachus grandisonae

Basso et al. (2011) assigned the monotypic genus Chaltenobatrachus for the species described originally as Telmatobius grandisonae Lynch, 1975 (later transferred to the genus Atelognathus by Lynch 1978). The type locality of Chaltenobatrachus grandisonae (L ynch, 1975) is Puer to Eden (Wellington Island) in the Magallanes Region, Chile, where the species has not been found again. Basso et al. (2011) added two new localities from Argentina and provided a detailed description that includes morphological and osteological characteristics of adult specimens, external morphology of tadpoles, kar yotype and phylogenetic relationships. They also provide a few fi eld observations, highlighting the lack of knowledge of the natural history and population biology of this anuran. In this work we repor t a new locality for C. grandisonae in Chile, extend its altitudinal distributional range and report on its reproductive mode. The study site is within the protected area Laguna Caiquenes (LCPA), located in the Aysen Region, which holds 9.000 ha of evergreen forests of Nothofagus betuloides and regrowth of Drimys winteri with bogs of Poaceae and Cyperaceae . In this locality, C. grandisonae cohabits with other fi ve anuran species: Alsodes coppingeri (Gunther, 1881); Batrachyla antar tandica Barrio, 1967; Batrachyla taeniata (Girard, 1855); Eupsophus calcaratus (Gunther, 1881) and Nannophryne variegata Gunther, 1870. Data on the reproductive activity of these species are also reported here. REVISTA CHILENA DE HISTORIA NATURAL

assigned the monotypic genus Chaltenobatrachus for the species described originally as Telmatobius grandisonae L ynch, 1975 (later transferred to the genus Atelognathus by Lynch 1978).The type locality of Chaltenobatrachus grandisonae (L ynch, 1975) is Puer to Edén (Wellington Island) in the Magallanes Region, Chile, where the species has not been found again.Basso et al. (2011) added two new localities from Argentina and provided a detailed description that includes morphological and osteological characteristics of adult specimens, external morphology of tadpoles, kar yotype and phylogenetic relationships.They also provide a few fi eld observations, highlighting the lack of knowledge of the natural history and population biology of this anuran.
In this work we repor t a new locality for C. grandisonae in Chile, extend its altitudinal distributional range and report on its reproductive mode.The study site is within the protected area Laguna Caiquenes (LCPA), located in the Aysén Region, which holds 9.000 ha of evergreen forests of Nothofagus betuloides and regrowth of Drimys winteri with bogs of Poaceae and Cyperaceae.In this locality, C. grandisonae cohabits with other fi ve anuran species: Alsodes coppingeri (Günther, 1881); Batrachyla antar tandica Bar rio, 1967;Batrachyla taeniata (Girard, 1855); Eupsophus calcaratus (Günther, 1881) and Nannophryne variegata Günther, 1870.Data on the reproductive activity of these species are also reported here.Field observations were performed during nine trips between October 2007 and December 2012.Individuals were searched in areas with water availability, captured and checked with a standard table of fi eld observations and then released at the same place where they were obser ved.Overall, 35 points were sampled, most of which were resurveyed on each trip.All procedures used comply with the laws of animal welfare in Chile (capture permit from the Servicio Agrícola Ganadero (SAG), resolution 5090 / 2011).

REVISTA CHILENA DE HISTORIA NATURAL
Our results indicate that C. grandisonae lays its eggs in clusters attached to branches or stones under the water (Fig. 2A and 2B).We found three clusters of 14, 21 and 30 eggs.Tadpoles develop in lentic waters (mainly temporary ponds) (Fig. 2C and 2D).Breeding sites are located in the pond edges (altitudinal range: 288 -942 masl; both records extend the altitudinal limits of this species).The amplexus is axillary (Fig. 2E) and parental care was not observed.This reproductive mode differs from that of the other fi ve species found in the area; none of these paste their eggs to a substrate.General descriptions of the reproductive modes of the other species were reported by Soto et al. (2008).
Observations throughout the six-year period showed that reproduction for C. grandisonae in this area begins with the amplexus and egg deposition in October (middle spring), following with larval development for 10 -12 weeks, and ending with metamorphosing tadpoles in December (early summer) (Fig. 2F).Oviposition of N. variegata was observed in September and lar val development was observed until November.Egg clutches of B. antartandica were obser ved from December through March and lar val development occur r ed thr oughout the year.Alsodes coppingeri also exhibits lar val development throughout the year.Metamorphs of A. coppingeri and B. taeniata were obser ved in January.No reproductive behavior of Eupsophus calcaratus was observed.
Antecedents reported here are the fi rst on the breeding biology of C. grandisonae.Our data differ from those of Basso et al. (2011), who suggested a prolonged development and overwintering of larvae in the water bodies.We observed two different types of ponds where the larval development of this species occurs.One corresponds to ponds within areas of forest re-growth where the substrate is organic matter that maintain temperatures above 0 ºC even when water surface freezes.The second type corresponded to temporal ponds located along the highway left after the road construction, in which water persists for four months.In fact, road construction also contributes with the This preliminary report on the phenology of reproduction of C. grandisonae and sympatric species in LCPA provide the basis for further studies on the autoecology and monitoring of these populations (e.g.Buckley & Beebee 2004).In par ticular, the poorly known C. grandisonae and A. coppingeri could be preferential targets for conser vation and management in this and other protected areas in the region.
R e p r o d u t i v e m o d e i s d e f i n e d b y a combination of characteristics including breeding site, clutch str ucture, location of egg deposition, lar val development site and parental care (Wells 2007, Vitt & Caldwell2009).Clutch structure was defi ned as the type of oviposition (rosary-like strings or clusters) and as parental care we considered any form of post-ovipositional parental behavior that could increase the sur vival of the offspring, such as nest attendance.Because temperature and rainfall are determinants of seasonality in anuran reproduction (V itt & Caldwell 2009), we repor t phenological changes of reproductive indicators (Fig.1A) in relation to these environmental factors (Fig.1B).

Fig. 2 :
Fig. 2: Microhabitat and life cycle stages of Chaltenobatrachus grandisonae.A) Eggs pasted to a branch under water.B) Enclosed embryos in a clutch pasted to a stone.C) Temporary pond located at the border of the Austral highway.D) Tadpoles in a pond with organic matter on the bottom.E) Adults in amplexus.F) Larvae in Gosner stages 32 and 43.Scale bars correspond to 1 cm.