Central African dwarf crocodiles found in syntopy are comparably divergent to South American dwarf caimans.

Recent molecular taxonomic advancements have expanded our understanding of crocodylian diversity, revealing the existence of previously overlooked species, including the Congo dwarf crocodile (Osteolaemus osborni) in the central Congo Basin rainforests. This study explores the genomic divergence between O. osborni and its better-known relative, the true dwarf crocodile (Osteolaemus tetraspis), shedding light on their evolutionary history. Field research conducted in the northwestern Republic of the Congo uncovered a locality where both species coexist in sympatry/syntopy. Genomic analysis of sympatric individuals reveals a level of divergence comparable to that between ecologically similar South American dwarf caimans (Paleosuchus palpebrosus and Paleosuchus trigonatus), suggesting parallel speciation in the Afrotropics and Neotropics during the Middle to Late Miocene, 10-12 Ma. Comparison of the sympatric and allopatric dwarf crocodiles indicates no gene flow between the analysed sympatric individuals of O. osborni and O. tetraspis. However, a larger sample will be required to answer the question of whether or to what extent these species hybridize. This study emphasizes the need for further research on the biology and conservation status of the Congo dwarf crocodile, highlighting its significance in the unique biodiversity of the Congolian rainforests and thus its potential as a flagship species.

A three-dimensional geometric morphometric analysis of the morphological transformation of Caiman lower jaw during post-hatching ontogeny.

Shape ontogenetic changes of the lower jaw in crocodylians are poorly understood. In order to answer some questions related to the inter- and intraspecific morphological variation of the mandible of two extant Caiman species, we performed a three-dimensional geometric morphometric approach. For this purpose, we used landmarks and semilandmarks on two ontogenetic mandibular series of 48 and 15 post-hatching specimens of C. yacare and C. latirostris, respectively. We have also examined the relationship between these anatomical transformations and ontogenetic shifts in diet. We performed a principal component analysis (PCA) for the two species, and regression and partial least squares (PLS) analyses for each species, separately. As a result, species were segregated along the PC1 with specimens of C. yacare showing more gracile mandibles, and specimens of C. latirostris more robust ones. The PC2 and regression analyses showed an age gradient and represented ontogenetic shape changes. Adult caiman mandibles are higher and wider than juvenile ones, and shape changes are more conspicuous in C. latirostris. The PLS analyses showed a significant relationship between shape and diet. Morphological changes of the PLS1 of block-1 match with those of the regression analysis for both species. We have detected morphological transformations in areas where the musculature in charge of mandibular movements is attached. Common morphological changes occurring during ontogeny seem to reflect the same mechanical properties required for crushing and killing in both species, driven by an ontogenetic shift in the diet from invertebrates to vertebrates. Additionally, interspecific differences were also found to be correlated to ontogenetic changes in diet and could be related to dissimilar feeding mechanical requirements (e.g., stiffness and toughness of the item consumed), and to different habitat preferences. Robust mandibles would be more suitable for shallow and fully vegetated environments, as it can be seen in C. latirostris, whereas slender jaws seem to be more suitable for more aquatic species such as C. yacare.

Cross-species chromosome painting and repetitive DNA mapping illuminate the karyotype evolution in true crocodiles (Crocodylidae).

Crocodilians have maintained very similar karyotype structures and diploid chromosome numbers for around 100 million years, with only minor variations in collinearity. Why this karyotype structure has largely stayed unaltered for so long is unclear. In this study, we analyzed the karyotypes of six species belonging to the genera Crocodylus and Osteolaemus (Crocodylidae, true crocodiles), among which the Congolian endemic O. osborni was included and investigated. We utilized various techniques (differential staining, fluorescence in situ hybridization with repetitive DNA and rDNA probes, whole chromosome painting, and comparative genomic hybridization) to better understand how crocodile chromosomes evolved. We studied representatives of three of the four main diploid chromosome numbers found in crocodiles (2n = 30/32/38). Our data provided new information about the species studied, including the identification of four major chromosomal rearrangements that occurred during the karyotype diversification process in crocodiles. These changes led to the current diploid chromosome numbers of 2n = 30 (fusion) and 2n = 38 (fissions), derived from the ancestral state of 2n = 32. The conserved cytogenetic tendency in crocodilians, where extant species keep near-ancestral state, contrasts with the more dynamic karyotype evolution seen in other major reptile groups.

Saurochory in crocodiles does not favor seed dispersai and viability / Saurocoría en cocodrilos no favorece la dispersión y la viabilidad de semillas

RESUMEN La dispersión de semillas por reptiles (saurocoría) ha recibido atención recientemente y se ha reportado el consumo de frutos y semillas en cocodrilianos, actuando como potenciales dispersores de semillas. Evaluamos si la saurocoría en Crocodylus actus y C. moreletii afecta la viabilidad de tres especies de plantas Delonixregia, Inga sp. y Citrullus lanatus. Se Utilizaron tres individuos juveniles de cada especie de cocodrilo y se alimentaron con 22 semillas por especie de planta, para un total de 66 semillas por recinto (132 para ambos). Las semillas se mezclaron con la dieta habitual cada semana, las semillas no consumidas y las excretadas se recolectaron y sembraron en suelo tratado con composta para evaluar la tasa de germinación relativa. Un total de 99 semillas fueron consumidas pero solo se recuperaron de las heces 14 semillas de C. lanatus, y germinando solo una de ellas (7, 14 %) con respecto al 50 % en el grupo control. Los resultados indican que la saurocoría de C. acutus y C. moreletii tiene un efecto negativo sobre la viabilidad de las semillas de las especies vegetales estudiadas, concordando con otros estudios realizados en diferentes especies.

ABSTRACT Seed dispersal by reptiles (saurochory) has recently received attention, and the consumption of fruits and seeds has been reported in crocodilians despite being mainly carnivores, acting as potential seed dispersers. We evaluate whether saurochory by Crocodylus acutus and C. moreletii affect the seed viability of three species of plants (Delonix regia, Inga sp., and Citrullus lanatus). We performed feeding trials, using three juvenile individuals of each species of crocodile, and fed them 22 seeds per plant species for a total of 66 seeds per enclosure (132 for both species). Seeds were combined with the usual diet each week. The unconsumed and excreted seeds were collected and planted in soil treated with compost to evaluate the relative germination rate. A total of 99 seeds were consumed, of which only 14 seeds of C. lanatus were recovered from the faeces, and only one of those germinated (7.14 %) with respect to 50 % in the control group. The results indicate that saurochory by C. acutus and C. moreletii has a negative effect on seed viability and germination of the plant species studied, as found in other studies using different species.

A "hotspot" within a hotspot: the reptiles of the Estação Ecológica and Área de Proteção Ambiental de Murici, Atlantic Forest of northeastern Brazil / Um "hotspot" dentro de um hotspot: os répteis da Estação Ecológica e Área de Proteção Ambiental de Murici, Mata Atlântica do nordeste do Brasil

Abstract: Currently the Atlantic Forest hotspot has less than 11% of its original coverage. However approximately 300 species of reptiles are known to inhabit this ecoregion, of which 34% are endemic. The creation of protected areas represents a strategy for preserving ecosystems and managing land use, and for attaining the proper management of these protected areas, information on local biodiversity is essential. Herein we provide the first list of reptile species for the Estação Ecológica and Área de Proteção Ambiental de Murici, two overlapping protected areas located in the state of Alagoas, one of the most important sets of forest remnants for the conservation of the Atlantic Forest in the northeast of Brazil. The species list was constructed based on expeditions and occasional encounters in the area between 1994 and 2022. A total of 89 reptile species were obtained during the 28 years of collection, being two species of Crocodylia, three species of Testudines and 84 species of Squamata. This richness is by far one of the greatest ever documented for the Atlantic Forest. Additionally, two species registered in the area are considered threatened according to the national list (Amerotyphlops paucisquamus and Bothrops muriciensis) and six are defined as data deficient for the assessment of their conservation status. Three species are recorded for the first time in the Atlantic Forest north of the São Francisco River: Dipsas indica, Trilepida salgueiroi and Cercophis auratus. We claim that the species list provided here will serve as a starting point for further studies in this rich reptile "hotspot" within the Atlantic Forest.

Resumo: Atualmente o hotspot da Mata Atlântica tem menos de 11% de sua cobertura original. Porém aproximadamente 300 espécies de répteis são conhecidas por habitar esta ecorregião, das quais 34% são endêmicas. A criação de unidades de conservação representa uma estratégia de preservação de ecossistemas e gestão do uso do solo, e para o manejo adequado dessas áreas protegidas é fundamental a informação sobre a biodiversidade local. Apresentamos aqui a primeira lista de espécies de répteis para a Estação Ecológica e Área de Proteção Ambiental de Murici, duas unidades de conservação parcialmente sobrepostas localizadas no estado de Alagoas, um dos conjuntos de remanescentes florestais mais importantes para a conservação da Mata Atlântica no nordeste do Brasil. A lista de espécies foi construída com base em expedições e encontros ocasionais na área entre 1994 e 2022. Um total de 89 espécies de répteis foram registradas durante os 28 anos de coleta, sendo duas espécies de Crocodylia, três espécies de Testudines e 84 espécies de Squamata. Essa riqueza é de longe uma das maiores já documentadas para a Mata Atlântica. Além disso, duas espécies registradas na área são consideradas ameaçadas segundo a lista nacional (Amerotyphlops paucisquamus e Bothrops muriciensis) e seis são definidas como dados insuficientes para a avaliação de seu status de conservação. Três espécies são registradas pela primeira vez na Mata Atlântica ao norte do rio São Francisco: Dipsas indica, Trilepida salgueiroi e Cercophis auratus. Afirmamos que a lista de espécies aqui fornecida servirá como ponto de partida para novos estudos neste rico "hotspot" de répteis dentro da Mata Atlântica.

Metallic elements in aquatic herpetofauna (Crocodylia; Testudines) from a lentic Atlantic rainforest environment in northeastern Brazil.

In the present study, Fe, Cu, Cr, Cd, Pb, Ni, and Al concentrations in Caiman latirostris and Testudines blood from the Tapacurá reservoir, Pernambuco, Brazil, were investigated. Blood was acid digested with HNO3, and metals were determined by ICP-OES and FAAS. Lead showed concentrations below the established limit of detection. Eighty animals were evaluated, forty from each group. The levels of all elements were statistically significant when compared between the two studied taxa (p < 0.05). In caimans, significant differences between young and adults were observed for chromium (p = 0.0539) and aluminum (p = 0.0515). Testudines showed no statistically significant differences for the variable age structure. Gender did not influence metal concentrations detected in the present study for either group. Differences between species of testudines were significant for Fe between Mesoclemmys tuberculata vs Phrynops geoffroanus (p = 0.0932) and Kinosternon scorpioides vs Phrynops geoffroanus (p = 0.063). The inter-elementary correlations showed statistically significant differences between the elements Cr vs Al (R2 = 0.52), Cr vs Cd (0.43), Cd vs Cu (R2 = 0.41), Ni vs Cu (R2 = 0.31), Ni vs Cr (R2 = 0.30), Al vs Cd (R2 = 0.27), and Cd vs Fe (R2 = 0.26). It is concluded that blood is an excellent predictor of metals in crocodilians and testudines in the Tapacurá reservoir, with statistically significant differences when correlated to concentrations such as size and species studied. In addition, it evidenced data that prove the exposure of these animals to metals, with strong inter-elementary correlations and opening doors for future studies that seek to understand possible biological effects caused in the studied taxa.

Allometric relations of respiratory variables in Amniota: Effects of phylogeny, form, and function.

Biological variables are frequently described by analyzing scaling relationships of the variable against body mass (MB). Respiratory variables are no exception and allometric relations for oxygen consumption, pulmonary ventilation, tidal volume, breathing frequency, and lung volume have been described in the literature. While the allometric relations of respiratory variables given for mammals and birds are very consistent among different studies, scaling relationships for non-avian reptiles have only been scarcely described and show considerable variation between studies. Since no comprehensive study of allometric relations of respiratory variables has been carried out comparing the different groups of non-avian reptiles, we analyzed morphological and physiological variables of the respiratory system of crocodilians, chelonians, lizards, snakes, birds, and mammals, regarding the allometric relations of each variable from a phylogenetic perspective as well as related to lung morphology. Our results indicated that few respiratory variables possess significant phylogenetic signals and that tidal volume, breathing frequency (except mammals), and air convection requirement were independent of phylogeny. Contrary to the literature, lung volume of amniotes scaled isometrically to MB, with the exception of lizards (MB0.78). Air convection requirement scaled isometrically in mammals and birds, but was more variable among non-avian reptiles, from a taxonomic perspective and in regard to different lung structures. In conclusion, respiratory variables among non-avian reptiles scaled more variably than previously expected, both according to phylogeny and to lung type, warranting future studies to explore structure-function relations of the reptilian respiratory system, especially regarding snakes and crocodilians, since these groups had very few data available for analysis.

On a new Melanosuchus species (Alligatoroidea: Caimaninae) from Solimões Formation (Eocene-Pliocene), Northern Brazil, and evolution of Caimaninae.

The Solimões Formation (Eocene-Pliocene) is a well-known geological unit due to the great diversity of crocodylian species. Here we describe a new species of Melanosuchus, M. latrubessei sp. nov., from the Talismã locality, state of Amazonas, from the Upper Miocene of the Solimões Formation (Solimões Basin, Brazil). A new phylogenetic inference focused on Caimaninae is provided and the different evolutionary scenarios involving this new species are discussed. In addition, quantitative morphology studies are carried out and comments regarding the paleoecology aspects of this new species are made. M. latrubessei represents a medium-sized generalist predator, being proportional to the medium-sized M. niger. This new species inhabited the drainages of the Solimões Formation and was ecologically related to other taxa of crocodylians during the proto-Amazon Miocene. The evolutionary advantages of Melanosuchus genus are discussed to better understand the biogeographical occurrence of M. niger in South America, a species which survives to this day in contrast to several other species that became extinct during the Miocene-Pliocene periods. The extinction of the Miocene-Pliocene crocodylian taxa of the Solimões Formation, including Melanosuchus latrubessei, seems to be directly related with the uplift of the northern portions of the Andes, which generated significantly changes in drainages and Amazon paleoenvironments.

Non-Avian Reptiles of the state of Rio de Janeiro, Brazil: status of knowledge and commented list

We assessed the current knowledge on non-avian reptile species composition in the state of Rio de Janeiro (RJ), southeastern Brazil. We used published data in indexed journals and verified voucher specimens housed in the herpetological collections of the Museu Nacional (UFRJ), and the Laboratory of Reptiles (ZUFRJ). We also confirmed vouchers from Instituto Vital Brazil (IVB) and from the Museum of Comparative Zoology (MCZ). We compiled a list containing 149 species of reptiles, distributed among Testudines (N = 15), Crocodylia (N = 1) and Squamata (N = 133; six amphisbaenians, 38 lizards and 89 snakes). Our results add 20 species to the previous list known for the state. Four species recorded are endemic to the state of Rio de Janeiro (Anolis neglectus, Glaucomastix littoralis, Leposternon scutigerum, and Liolaemus lutzae). We identified that 21 reptile species recorded in RJ state (nearly 15% of the total) are included in some threat category either in the IUCN, Brazilian (ICMBio) or state lists of endangered species. We also report that seven of the reptiles recorded are non-indigenous to the state: Cnemidophorus aff. lemniscatus (= Cnemidophorus cryptus), Anolis sagrei, Trachemys scripta, Trachemys dorbigni, Hemidactylus mabouia, Crotalus durissus terrificus, and Rhinoclemmys punctularia. The checklist presented here provides a comprehensive database for further research on the herpetofauna of the Brazilian Atlantic Forest.(AU)

Non-Avian Reptiles of the state of Rio de Janeiro, Brazil: status of knowledge and commented list

We assessed the current knowledge on non-avian reptile species composition in the state of Rio de Janeiro (RJ), southeastern Brazil. We used published data in indexed journals and verified voucher specimens housed in the herpetological collections of the Museu Nacional (UFRJ), and the Laboratory of Reptiles (ZUFRJ). We also confirmed vouchers from Instituto Vital Brazil (IVB) and from the Museum of Comparative Zoology (MCZ). We compiled a list containing 149 species of reptiles, distributed among Testudines (N = 15), Crocodylia (N = 1) and Squamata (N = 133; six amphisbaenians, 38 lizards and 89 snakes). Our results add 20 species to the previous list known for the state. Four species recorded are endemic to the state of Rio de Janeiro (Anolis neglectus, Glaucomastix littoralis, Leposternon scutigerum, and Liolaemus lutzae). We identified that 21 reptile species recorded in RJ state (nearly 15% of the total) are included in some threat category either in the IUCN, Brazilian (ICMBio) or state lists of endangered species. We also report that seven of the reptiles recorded are non-indigenous to the state: Cnemidophorus aff. lemniscatus (= Cnemidophorus cryptus), Anolis sagrei, Trachemys scripta, Trachemys dorbigni, Hemidactylus mabouia, Crotalus durissus terrificus, and Rhinoclemmys punctularia. The checklist presented here provides a comprehensive database for further research on the herpetofauna of the Brazilian Atlantic Forest.

Non-Avian Reptiles of the state of Rio de Janeiro, Brazil: status of knowledge and commented list

Abstract We assessed the current knowledge on non-avian reptile species composition in the state of Rio de Janeiro (RJ), southeastern Brazil. We used published data in indexed journals and verified voucher specimens housed in the herpetological collections of the Museu Nacional (UFRJ), and the Laboratory of Reptiles (ZUFRJ). We also confirmed vouchers from Instituto Vital Brazil (IVB) and from the Museum of Comparative Zoology (MCZ). We compiled a list containing 149 species of reptiles, distributed among Testudines (N = 15), Crocodylia (N = 1) and Squamata (N = 133; six amphisbaenians, 38 lizards and 89 snakes). Our results add 20 species to the previous list known for the state. Four species recorded are endemic to the state of Rio de Janeiro (Anolis neglectus, Glaucomastix littoralis, Leposternon scutigerum, and Liolaemus lutzae). We identified that 21 reptile species recorded in RJ state (nearly 15% of the total) are included in some threat category either in the IUCN, Brazilian (ICMBio) or state lists of endangered species. We also report that seven of the reptiles recorded are non-indigenous to the state: Cnemidophorus aff. lemniscatus (= Cnemidophorus cryptus), Anolis sagrei, Trachemys scripta, Trachemys dorbigni, Hemidactylus mabouia, Crotalus durissus terrificus, and Rhinoclemmys punctularia. The checklist presented here provides a comprehensive database for further research on the herpetofauna of the Brazilian Atlantic Forest.

The sex-determination pattern in crocodilians: A systematic review of three decades of research.

Sex in crocodilians is not determined by chromosomes, but by egg incubation temperature, where different temperatures produce different clutch sex ratios. Two patterns have been proposed to describe these changes in sex ratios: a 100% female proportion at low and high temperatures with male predominance at intermediate ones (FMF) or a simpler pattern with a single female-to-male transition (FM). Over the last three decades, researchers have provided empirical information to support either of these two patterns in different species; however, no consensus has been reached partly because data have not been analysed as a whole. Here, we aimed at gathering the existing data on these patterns to provide models of temperature-dependent sex determination in those crocodilians studied so far. Potentially relevant publications were searched on Web of Knowledge, Scopus, Scielo and Science Direct. Studies that reported results on the sexual identity of crocodilian hatchlings obtained from constant temperature incubation treatments were considered. Using statistical models varying in their underlying assumptions, we evaluated which sex-determination pattern was best supported for the studied crocodilians and constructed species-specific and latitude-specific models. Based on the 8,458 sexed hatchlings studied throughout 31 studies, we show that the evidence supports a shared FMF pattern in all the crocodilian species for which enough data are available. We find that such pattern changes between species and at different latitudes. These results suggest a lability of the FMF crocodilian sex-determination pattern, a key feature under the present climate change scenario.

Revisiting Gryposuchus jessei Gürich, 1912 (Crocodylia: Gavialoidea): specimen description and comments on the genus.

Gryposuchus Gürich, 1912 is the most diverse genus within the Gavialoidea. However, the type species G. jessei Gürich, 1912 has been subject of controversy and was regarded conspecific with G. neogaeus (Burmeinster, 1885) or G. colombianus (Langston, 1965). Here we provide a revision of G. jessei to verify the conspecific hypothesis and the implications for the genus Gryposuchus. Our study shows that G. jessei is a valid species, and a new specimen was referred to this taxon. The comparisons with other Gavialoidea species enabled the proposition of three exclusive characters for the genus. We further advocate a sister affinity between G. jessei and G. pachakamue.

Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha).

Many of the major locomotor transitions during the evolution of Archosauria, the lineage including crocodiles and birds as well as extinct Dinosauria, were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and function in several lineages, including sauropodomorph dinosaurs. We present biomechanical computer models of two locomotor extremes within Archosauria in an analysis of joint ranges of motion and the moment arms of the major forelimb muscles in order to quantify biomechanical differences between more sprawling, pseudosuchian (represented the crocodile Crocodylus johnstoni) and more erect, dinosaurian (represented by the sauropodomorph Mussaurus patagonicus) modes of forelimb function. We compare these two locomotor extremes in terms of the reconstructed musculoskeletal anatomy, ranges of motion of the forelimb joints and the moment arm patterns of muscles across those ranges of joint motion. We reconstructed the three-dimensional paths of 30 muscles acting around the shoulder, elbow and wrist joints. We explicitly evaluate how forelimb joint mobility and muscle actions may have changed with postural and anatomical alterations from basal archosaurs to early sauropodomorphs. We thus evaluate in which ways forelimb posture was correlated with muscle leverage, and how such differences fit into a broader evolutionary context (i.e. transition from sprawling quadrupedalism to erect bipedalism and then shifting to graviportal quadrupedalism). Our analysis reveals major differences of muscle actions between the more sprawling and erect models at the shoulder joint. These differences are related not only to the articular surfaces but also to the orientation of the scapula, in which extension/flexion movements in Crocodylus (e.g. protraction of the humerus) correspond to elevation/depression in Mussaurus. Muscle action is highly influenced by limb posture, more so than morphology. Habitual quadrupedalism in Mussaurus is not supported by our analysis of joint range of motion, which indicates that glenohumeral protraction was severely restricted. Additionally, some active pronation of the manus may have been possible in Mussaurus, allowing semi-pronation by a rearranging of the whole antebrachium (not the radius against the ulna, as previously thought) via long-axis rotation at the elbow joint. However, the muscles acting around this joint to actively pronate it may have been too weak to drive or maintain such orientations as opposed to a neutral position in between pronation and supination. Regardless, the origin of quadrupedalism in Sauropoda is not only linked to manus pronation but also to multiple shifts of forelimb morphology, allowing greater flexion movements of the glenohumeral joint and a more columnar forelimb posture.

Osteologia de Melanosuchus niger (Crocodylia: Alligatoridae) e a evidência evolutiva / Osteology of Melanosuchus niger (Crocodylia: Alligatoridae) and the evolutionary evidence

O objetivo foi realizar a descrição anatômica do esqueleto de Melanosuchus niger, com o intuito de contribuir com informações evolutivas sobre a espécie. Utilizaram-se três espécimes adultos de M. niger, com comprimento médio de 2,40m, provenientes da coleção biológica do Lapas-UFU. Na cintura peitoral, a escápula é maior do que o coracóide. Já nos elementos da cintura pelvina, o púbis não participa da formação do acetábulo, o contato com o ilío, ocorre por ligamentos, e sua articulação com o ísquio, permite movimentos dorso-ventrais. Nos membros torácicos, o úmero figura como elemento do estilopódio, a ulna e rádio como elementos do zeugopódio. No carpo há o ulnar do carpo, fusão do radial+intermédio, fusão dos distais do carpo 3+4+5 e o pisiforme; possui cinco metacarpos, numerados lateromedialmente e a fórmula falângica 2:3:4:3:2. Nos membros pelvinos, o estilopódio é formado pelo fêmur e o zeugopódio pela tíbia e fíbula. No tarso há a fusão do intermédio+central, fibular do tarso, distal do tarso 3, distal do tarso 4; possui quatro metatarsos longos I, II, III e IV, sendo os metatarsos II e III maiores que os demais. O metatarso V é um osso bastante reduzido e o pé possui a fórmula falângica 2:3:4:4. No crânio, a abertura nasal é única, o palatino, vômer, pterigóide, pré-maxila e maxila formam a estrutura óssea do palato secundário; o osso parietal é o único elemento no teto craniano. No esqueleto pós- axial em pares de costelas distintas que se articulam com as vértebras cervicais, dorsais, lombares, sacrais e caudais. A gastrália é formada por sete fileiras de ossos finos localizados entre o púbis e a região caudal do esterno.(AU)

The objective was an anatomical description of the skeleton of Melanosuchus niger, in order to contribute with evolutionary information about the species. Three adult specimens of M. niger with an average length of 2.40m were used, originating from the biologic collection of Lapas-UFU. In the forelimb, the scapula is bigger than the coracoid. Regarding the hindlimbs, the pubic does not participate in the formation of the acetabulum; the contact with the ilium is made by ligaments, and its articulation with the rump allows dorsal-ventral movements. Regarding the forelimbs, the humerus is a stylopodium element, and the ulna and radius a zeugopodium element. The carpus exibits the ulnar-radial+intermedium fusion, fusion of the distal carpals 3+4+5, and the pisiform. It has five metacarpals, numbered lateromedially as metacarpal 1, 2, 3, 4, and 5. The phalangeal formula is 2:3:4:3:2. Regarding the pelvic limbs, the stylopodium is formed by the femur, and the zeugopodium by tibia and fibula. In tarsus has four bones: fusion of the intermedium+centrale, fibulare, distal tarsal 3, and distal tarsal 4. It has four long metatarsals I, II, III and IV, with metatarsal II and III being relatively longer than the others. Metatarsal V is a very small bone; the feet have the phalangeal formula 2:3:4:4. At the skull, the nasal opening is only the palatine bones, vomer, pterygoid, premaxilla and maxilla forming the bone structure of the secondary palate; the parietal bone is the only element on the cranial roof. In the pos- axial skeleton ist distinct pairs of ribs which articulate with the cervical, dorsal, lumbar, sacral and caudal vertebrae. The gastralia consists of seven rows of fine bone located between the pubic bone and caudal part of the sternum.(AU)

Osteologia de Melanosuchus niger (Crocodylia: Alligatoridae) e a evidência evolutiva / Osteology of Melanosuchus niger (Crocodylia: Alligatoridae) and the evolutionary evidence

The objective was an anatomical description of the skeleton of Melanosuchus niger, in order to contribute with evolutionary information about the species. Three adult specimens of M. niger with an average length of 2.40m were used, originating from the biologic collection of Lapas-UFU. In the forelimb, the scapula is bigger than the coracoid. Regarding the hindlimbs, the pubic does not participate in the formation of the acetabulum; the contact with the ilium is made by ligaments, and its articulation with the rump allows dorsal-ventral movements. Regarding the forelimbs, the humerus is a stylopodium element, and the ulna and radius a zeugopodium element. The carpus exibits the ulnar-radial+intermedium fusion, fusion of the distal carpals 3+4+5, and the pisiform. It has five metacarpals, numbered lateromedially as metacarpal 1, 2, 3, 4, and 5. The phalangeal formula is 2:3:4:3:2. Regarding the pelvic limbs, the stylopodium is formed by the femur, and the zeugopodium by tibia and fibula. In tarsus has four bones: fusion of the intermedium+centrale, fibulare, distal tarsal 3, and distal tarsal 4. It has four long metatarsals I, II, III and IV, with metatarsal II and III being relatively longer than the others. Metatarsal V is a very small bone; the feet have the phalangeal formula 2:3:4:4. At the skull, the nasal opening is only the palatine bones, vomer, pterygoid, premaxilla and maxilla forming the bone structure of the secondary palate; the parietal bone is the only element on the cranial roof. In the pos- axial skeleton ist distinct pairs of ribs which articulate with the cervical, dorsal, lumbar, sacral and caudal vertebrae. The gastralia consists of seven rows of fine bone located between the pubic bone and caudal part of the sternum.(AU)

O objetivo foi realizar a descrição anatômica do esqueleto de Melanosuchus niger, com o intuito de contribuir com informações evolutivas sobre a espécie. Utilizaram-se três espécimes adultos de M. niger, com comprimento médio de 2,40m, provenientes da coleção biológica do Lapas-UFU. Na cintura peitoral, a escápula é maior do que o coracóide. Já nos elementos da cintura pelvina, o púbis não participa da formação do acetábulo, o contato com o ilío, ocorre por ligamentos, e sua articulação com o ísquio, permite movimentos dorso-ventrais. Nos membros torácicos, o úmero figura como elemento do estilopódio, a ulna e rádio como elementos do zeugopódio. No carpo há o ulnar do carpo, fusão do radial+intermédio, fusão dos distais do carpo 3+4+5 e o pisiforme; possui cinco metacarpos, numerados lateromedialmente e a fórmula falângica 2:3:4:3:2. Nos membros pelvinos, o estilopódio é formado pelo fêmur e o zeugopódio pela tíbia e fíbula. No tarso há a fusão do intermédio+central, fibular do tarso, distal do tarso 3, distal do tarso 4; possui quatro metatarsos longos I, II, III e IV, sendo os metatarsos II e III maiores que os demais. O metatarso V é um osso bastante reduzido e o pé possui a fórmula falângica 2:3:4:4. No crânio, a abertura nasal é única, o palatino, vômer, pterigóide, pré-maxila e maxila formam a estrutura óssea do palato secundário; o osso parietal é o único elemento no teto craniano. No esqueleto pós- axial em pares de costelas distintas que se articulam com as vértebras cervicais, dorsais, lombares, sacrais e caudais. A gastrália é formada por sete fileiras de ossos finos localizados entre o púbis e a região caudal do esterno.(AU)

Food conversion rate (FCR) in Caiman latirostris resulted more efficient at higher temperatures / La tasa de conversión alimenticia (FCR) de Caiman latirostris resulta más eficiente a temperaturas altas / A Taxa de conversão do alimento (FCR) do Caiman latirostris é mais eficiente a temperaturas mais elevadas

The effects of temperature on the growth of Caiman latirostris were investigated in order to evaluate the efficiency of food conversion at 29 and 33°C. Sixty-eight captive raised animals, two months old, taken from four nests, were used. All groups were maintained up to 70 or 72 days in similar environmental treatments except for temperature. Animals maintained at 33°C reached greater body mass (BM) and total length (TL) than those maintained at 29°C. A more efficient nutritional conversion rate was found in animals kept at 33°C. The increase of temperature could improve the amount of energy extracted from food, producing a more efficient FCR.

El efecto de la temperatura sobre el crecimiento de Caiman latirostris fue estudiado a fin de evaluar la eficacia de la conversión alimenticia en cautiverio a 29 y 33°C. Fueron utilizados 68 animales cautivos de dos meses de edad, provenientes de cuatro nidadas. Todos los grupos fueron mantenidos hasta por 70 o 72 días en tratamientos ambientales similares, a excepción de la temperatura. Los animales mantenidos a 33°C alcanzaron mayor peso y longitud total que aquellos mantenidos a 29°C. Una tasa de conversión alimenticia más eficiente fue encontrada en los animales criados a 33°C. El aumento de la temperatura podría mejorar la cantidad de energía extraída del alimento, produciendo un FCR más eficiente.

Para avaliação de um método econômico na criação em cativeiro de Jacaré-de-Papo-Amarelo (Caiman latirostris) estudio-se o consumo de ração, a taxa de conversão e o efeito da temperatura de cria no crescimento da espécie. Para este estudo foram utilizados 68 jacarés de dois meses de idade, nascidos de quatro ninhos coletados na natureza e incubados artificialmente. Durante o experimento os animais foram mantidos a duas temperaturas: 29ºC e 33ºC até 70 ou 72 dias. Como esperado, os animais mantidos a 33ºC mostraram maior taxa de crecimento (comprimento total e peso), e maior consumo de ração que aqueles mantidos a 29ºC. A taxa de conversão de alimento também foi mais efetiva quando a temperatura de cria foi maior. Concluí-se que o aumento da temperatura poderia melhorar a quantidade de energia extraída da ração, produzindo uma taxa de conversão mais eficiente.