Leonardo Cotts

The Iberian wolf ( Canis lupus signatus ) is an endangered subspecies characterized by highly fragmented populations and increasing human–carnivore conflict across the Iberian Peninsula. Although body mass strongly influences predator–prey dynamics and ecological performance, quantitative assessments of sexual size dimorphism (SSD) and body mass (BM) variation in this subspecies remain scarce. Here, we conducted a morphometric analysis of the lower carnassial tooth (m1) in 78 historical and contemporary museum specimens (1900–2006) to evaluate its applicability for non‐invasive body mass estimation and sex discrimination. We assessed the anteroposterior length (m1L) and blade length (m1BL) as potential proxies for BM and SSD. Multivariate analyses (MANOVA) based on m1L and m1BL revealed significant morphometric differences between sexes (Pillai's trace = 0.3488, p < 0.001), and Linear Discriminant Analysis produced a cross‐validated classification accuracy of 79.07%. We further developed a predictive equation specifically calibrated for the Iberian wolf using m1L, achieving a mean absolute error of 2.44 kg and a mean absolute percentage error of 7.58% under leave‐one‐out cross‐validation, demonstrating robust predictive performance for mature individuals. In immature specimens, the equation likely estimates expected adult body mass, consistent with earlier dental maturation relative to overall skeletal growth. Sexual size dimorphism was further supported by body mass estimates, with males being on average 21.4% (RBM) and 11.6% (EBM) heavier than females. Spatial analyses indicated morphological stability, with no significant differences in body mass between mature males from north and south of the Douro River, Portugal. Comparative analyses within Canis place the Iberian wolf within the range of variation of medium‐sized wolves. Overall, carnassial morphometrics provide a robust and accurate approach for assessing ecomorphological traits, offering valuable data to support field monitoring, forensic applications, and conservation research in threatened canids.

Coatis ( Nasua ) are diurnal, gregarious mesocarnivores widely distributed across the Americas. Chromatic disorders are rarely documented in this genus. Here, we report the first record of xanthochromism in Nasua , based on two individuals of N. nasua observed in Tijuca National Park, Brazil, one of the largest urban forests in the world. The xanthochromic individuals exhibited a markedly yellow-orange coat, differing from the typical coloration of the species. Records were restricted to edge areas, suggesting a potential spatial association with environmental conditions, including anthropogenic disturbance. This finding provides new insights into phenotypic variation in coatis and highlights the potential influence of environmental conditions on the emergence of anomalous coloration in urban–forest interface areas.

Caiman latirostris is a neotropical crocodilian widely distributed in Brazil, marked by a greenish-brown body, except by a yellowish-cream venter. Chromatic disorders remain unreported for C. latirostris . Here, we describe the first case of leucism in a C. latirostris and provide clinical, biometric and morphological data on this individual, including body condition index (BCI), body condition scores (qBCS and BCS), and haematological, biochemical and parasitological analyses. Additionally, we discuss the historical occurrence of the white phenotype in crocodilians and its potential as a bioindicator of environmental stress and ecosystem health.

Mustelidae is the largest and most diverse family within the order Carnivora, encompasses 65 species and 22 genera, and is widely distributed around the world. Mustelids exhibit a multiplicity of coloration patterns, ranging from darker tones, such as black and brown, to lighter tones, such as pale yellow and white. Anomalous colorations in wild mustelids are occasionally reported, but these records are still poorly discussed in the scientific literature and are often subject to misidentification and/or incorrect terminology. Among mustelids, the Tayra, Eira barbara, is suggested to have the highest frequency of chromatic disorders reported in the formal scientific literature, although most cases involve hypopigmentation. Here, we report and describe the first case of a reddish-colored tayra, a rare chromatic disorder known as erythrism, and compare their coloration to that observed in the subspecies currently suggested for E. barbara. We also conducted a survey and a review of chromatic variants in mustelids based on the formal scientific literature, reporting 119 anomalously colored individuals from 1890 to 2024, and proposed accurate terminology for misidentified cases. Additionally, we discuss the occurrence of these chromatic disorders on a global scale and their potential ecological effect on wild mustelids.

Didelphis aurita is an abundant South American didelphid. Chromatic disorders are rare and scarcely known in marsupials. We report and describe the occurrence of xanthochromism (yellowish coloration) in D. aurita, being the first record of this anomaly for opossums. The emergence of the xanthochromism correlated with the anthropogenic stress in urban-sylvatic interface suggests that chromatic disorders may serve as useful bioindicators of the health of wildlife in disturbed environments.

FIRST REPORT AND DESCRIPTION OF MELANISM AND ALBINISM IN GIANT ANTEATER, MYRMECOPHAGA TRIDACTYLA (XENARTHRA, MYRMECOPHAGIDAE)

The southern tamandua, Tamandua tetradactyla (Linnaeus, 1758), is the most common species of anteater. Even though much is known about its ecology, behavior, and parasites, there is very limited information about bone diseases in Tamandua and other anteaters. Here, we examined postcranial skeletons of 64 T. tetradactyla museum specimens covering most of the material available in Brazilian collections. The following bone diseases were identified for the first time in Tamandua and other extant and fossil vermilinguans: osteophytes, osteitis, osteoarthritis, periostitis, exostoses, enthesopathies, and a severe chronic pyogenic osteomyelitis associated with fistulae, cloacae (pus), bone loss, and neoformation processes. Musculoskeletal reconstruction revealed that an old specimen was restricted to terrestrial locomotion due to osteopathological processes that impaired its climbing. New osteopathological informations are presented for T. tetradactyla, favoring a better understanding of the expression of some bone diseases in wild animals. In addition, the diagnosis of these bone diseases in living anteaters provides useful information for studies on animal health and welfare, as well as contributing to the more effective recognition of paleodiseases in fossil xenarthrans.

The evolution of the human species is a topic of extreme importance reported in the “Parâmetros Curriculares Nacionais do Ensino Médio – PCNEM” (National Curriculum Standards of Secondary Education), although it is not often taught as part of basic education. This work presents the results of an experimental work performed with 31 students of a religious high school of State of Rio de Janeiro. Learning proficiency was assessed by using two-dimensional (2D) and three-dimensional (3D) illustration techniques of hominids skulls and a Pongidae for teaching Human Evolution. The teaching-learning process using these methodologies was more effective with the application of three-dimensional (3D) illustration techniques. The group of students that used 3D illustrations were able to observe similarities and differences between the presented taxonomic models, and formulate hypotheses about their palaeobiology more consistently than the students that used 2D models. Results of this work indicate that the use of three-dimensional techniques (3D) provides an excellent support to teaching-learning process in basic education, captivating and stimulating new interests of students during the educational process.