Leandro Alcalde

Feeding in Syntopy: Diet of Hydromedusa tectifera and Phrynops hilarii (Chelidae)

Abstract Stomach contents were obtained from 25 Hydromedusa tectifera and 47 Phrynops hilarii that live in syntopy in a pampasic stream in Buenos Aires province, Argentina. Both species are arthropod consumers. Copepods, ostracods, and hemipterans are the preferred items for P. hilarii, and H. tectifera prefers copepods, ostracods, immature dipterans (mainly chironomids), and ephemeropteran larvae. Items that most contribute to the diet of both species are immature chironomids, corixids, and belostomatids. Available food varies little among seasons, being slightly lower in winter months and part of the summer. Diet diversity changes by seasonal variation of prey item abundance in the diet of both species. Diet diversity is higher for P. hilarii (more generalist and broader trophic niche) than in H. tectifera, but there is no niche overlap between them. No significant correlation between the size of turtles and length of prey items was found. There is no evidence that the long neck of H. tectifera relates to piscivorous habits, because fish are a small fraction of its diet and arthropods constitute the bulk of the ingested items.

A REVISION OF ODONTOPHRYNUS BARRIOI (ANURA: NEOBATRACHIA): MORPHOLOGY, OSTEOLOGY, VOCALIZATIONS, AND GEOGRAPHIC DISTRIBUTION

Abstract The present paper provides diagnostic characters from external morphology and osteology that reinforce the specific recognition of the frog Odontophrynus barrioi, describes its advertisement and encounter calls, and extends its distribution range. Odontophrynus barrioi is distinguished from all other species of the genus principally by the large size of adults, great number of irregularly arranged postorbital and temporal glands, lack of both a light vertebral line and keratinous spines, alary process of the premaxilla short and wide, pterygoid process of the maxilla well developed, and high preorbital process of the maxilla. The advertisement call consists of a trill of a single repeated and pulsed note with a low dominant frequency. The encounter call consists of only one note of similar frequency as the advertisement call, but longer in time duration. We report new records of O. barrioi from Catamarca, La Rioja, and San Juan Provinces (Argentina), that increase considerably the range of this previously poorly known species.

Chondrocranium, cranial muscles and buccopharyngeal morphology on tadpoles of the controversial leptodactylid frog Limnomedusa macroglossa (Anura: Leptodactylidae)

The present paper provides original data on the chondrocranium, cranial muscles, oral disc and buccopharyngeal morphology of Limnomedusa macroglossa . We found that the cranial muscles and the buccopharyngeal papillation are not useful to relate Limnomedusa either to telmatobiine or leptodactyline genera. There are two chondrocranial characters (presence of a long processus pseudopterygoideus and sindesmotic connection of the partes alares and partes corpora of the cartilago suprarostralis) that relate Limnomedusa to the telmatobiine genera more than to any other genus within Leptodactylidae. Additionally, the processus pseudopterygoideus of Limnomedusa is fused to the basi cranii, a character state only known for some telmatobiine genera such as Alsodes and Telmatobius .

Southernmost Localities of Trachemys dorbigni and First Record of Trachemys scripta elegans for Argentina (Cryptodira: Emydidae)

Abstract We report two new localities for Trachemys dorbigni that expand the southern range border for approximately 120 km. These new localities are Arroyo Buñirigo and Arroyo Zapata. Both are streams related to the Río de La Plata shoreline at Buenos Aires province, Argentina. We also record the nonnative Trachemys scripta elegans for the first time for Argentina.

Old and new hypotheses about the homology of the compound bones from the cheek and otico-occipital regions of the anuran skull

We studied the larval development of compound bones from the otico-occipital and cheek regions in species of the neobatrachian genera Batrachyla, Hylorina, Leptodactylus, Odontophrynus and Pleurodema. Comparisons were made using a set of Ambystoma spp. (Caudata) and Ceratophrys ornata (Anura; Ceratophryidae) larvae. As suggested by previous studies, we verified the compound nature of the exoccipital (two centers, anurans only), frontoparietal (one center, most anurans and Ambystoma; three centers, some anurans), and squamosal (two centers, all anurans and Ambystoma) bones. We discuss old and new homology hypotheses for each of the compound bone centers in the context of the most widely accepted scenario of lissamphibian origins and relationships, i.e., monophyletic Lissamphibia that includes the clade Batrachia (Caudata+Anura) and the most divergent Gymnophiona. Our findings have a direct impact on our understanding of the composition of the skull in Lissamphibia. We recognized the presence of the following bones: (i) opisthotic (fused to the exoccipital) and tabular (fused to the squamosal) in Batrachia (Anura+Caudata) and (ii) supratemporal (fused to the parietal portion of the frontoparietal) in Anura. Separate centers of the parietal were found only in Pleurodema.

Spiroxys contortus (Rudolphi, 1819) and Hedruris orestiae (Moniez, 1889) in Argentine turtles

Knowledge of parasites in turtles is scarce, particularly with regard to freshwater turtles of South America. Here, we describe the association of Spiroxys contortus (Rudolphi, 1819) in Phrynops hilarii (Dumeril & Bibron, 1835) and S. contortus and Hedruris orestiae (Moniez, 1889) in Hydromedusa tectifera (Cope, 1870) . The presence of S. contortus in P. hilarii represents a new host record and also the southernmost geographic record for this species. More interestingly, the presence of H. orestiae in H. tectifera represents the first record of this helminth species from a reptilian host.

On the anuran muscle pulmonum proprius

The present contribution provides a systematic survey on the variation of the musculus pulmonum proprius within Anura. Evidence is contrary to previous works that presented the muscle as an enigmatic feature present only in the family Pipidae. Although having different sites of origin, the m. pulmonum proprius was observed in all examined anurans. The muscle originates at the level of the transverse processes of the fourth vertebra in the neobatrachian families Bufonidae, Calyptocephalellidae, Ceratophryidae, Cycloramphidae, Dendrobatidae, Hylidae, Hylodidae, Leiuperidae, Leptodactylidae, Mantellidae, Microhylidae, Ptychadenidae and Ranidae. In Bombina variegata (Bombinatoridae) the origin of the muscle shifts caudally at the level of the transverse process of the sacral vertebra and, in Pipidae, it originates either at the ilium ( Xenopus ) or the femur ( Pipa ). Features of the m. pulmonum proprius do not vary in species with different modes of locomotion within Neobatrachia and there is no sexual dimorphism in this muscle. It is absent in the genera Salamandra (Caudata) and Chthonerpeton (Gymnophiona). Pending verification in Leiopelmatidae, the presence of m. pulmonum proprius may be considered as a previously unknown anuran synapomorphy.

An Easy, Cheap, and Versatile Method to Trap Turtles, with Calibrated Sampling Effort

Abstract. A novel method (hookless trot line) to trap freshwater turtles in aquatic environments from the Pampas region on southern South America is presented. Cost, functioning, effectiveness, biases, maintenance, and constraints of the hookless trot line are analyzed compared to three other methods (two variants of funnel traps and a trawl net) commonly used in studies dealing with freshwater turtle ecology. Fieldwork was carried out from 2005–2015 in streams that drain the northeast of Buenos Aires province, Argentina. The beef-baited, single-mouthed funnel trap with drift fences was the method that captured the most turtles. It was closely followed by the hookless trot line, whereas the other two methods obtained a small portion of captures. Nevertheless, we conclude that the best method to trap turtles in the region was the hookless trot line because it adapts to a wide range of environments, does not injure the turtles, is easy to build and transport, requires little maintenance, and its materials are cheaper and more durable than those of the other methods. Further, a calibration for the trot line is provided in order to minimize effort and maximize captures: in cost/benefit terms, the best result was achieved by employing 1 bait/1.5 m of shoreline.

Internal features of larvae belonging to two species of Pseudopaludicola (Anura: Leiuperinae)

We described the buccal cavity, chondrocranium, and cranial muscles in tadpoles of two species of Pseudopaludicola: P. boliviana (P. pusilla species group) and P. falcipes. The two species share states of only three relevant and informative characters: (1) absence of m. levator mandibularis lateralis, (2) absence of m. levator mandibularis externus superficialis at advanced premetamorphic stages, and (3) presence of long lateral arena papillae of both the roof and floor of the buccal cavity. The larvae of P. falcipes is diagnosed by (states of P. boliviana between parentheses): (1) three lingual papillae (four), (2) one-two pairs of short and blunt infralabial papillae (single pair of multifid papillae), (3) low median ridge (tall), (4) distal connection between pars corpora and pars alaris of the cartilago suprarostralis present (absent), and (5) m. subarcualis rectus II-IV inserted at ceratobranchiale I (ceratobranchiale II insertion). The combination of a processus pseudopterygoideus together with proximal and distal connections on the cartilago suprarostralis occurs in most species of Pleurodema as well. Absence of m. levator mandibularis lateralis is also known for Physalaemus fernandezae and absence of m. levator mandibularis externus superficialis at advanced stages of development (Stage 39 onward) is shared with Edalorhina perezi and Pleurodema diplolister.

External Morphology, Chondrocranium, Cranial Muscles, and Buccopharyngeal Features of Tadpoles of Pleurodema thaul (Anura: Leiuperidae): a Comparison with P. bufoninum

Abstract This article describes the external and buccopharyngeal morphology, chondrocranium, and cranial muscles in tadpoles of Pleurodema thaul from Argentina. Further comparison was made with larvae of other Pleurodema species, particularly P. bufoninum. The larvae of P. thaul possess: (1) tooth row formula 2(2)/3(1), (2) single to double row of marginal papillae with wide rostral gap, (3) presence of long processus pseudopterygoideus, (4) pars alaris and pars corpora of the cartilago suprarostralis joined by both proximal and distal connections, and (5) larval processus oticus present. In the light of the available evidence, the larvae of Pleurodema are characterized by (1) medium size (total length  =  35.4–48.7 mm); (2) medium-sized tail (0.63 times of total length); (3) rounded snout; (4) nostrils closer to the eyes than to the snout; (5) vent tube opening medial; (6) tail tip rounded; and (7) oral disc subterminal with angular constrictions and rostral gap present. In Leiuperidae, the cartilaginous distal connection between pars alaris and pars corpora of the cartilago suprarostralis is present only in Pleurodema. In addition, all Pleurodema studied to date have processus pseudopterygoideus (shared with Eupemphix and Physalaemus marmoratus). Finally, within Pleurodema, the larval processus oticus is present only in P. thaul and P. bufoninum.