Changes in body surface temperature reveal the thermal challenge associated with catastrophic moult in captive gentoo penguins.

Once a year, penguins undergo a catastrophic moult, replacing their entire plumage during a fasting period on land or on sea-ice during which time individuals can lose 45% of their body mass. In penguins, new feather synthesis precedes the loss of old feathers, leading to an accumulation of two feather layers (double coat) before the old plumage is shed. We hypothesized that the combination of the high metabolism required for new feather synthesis and the potentially high thermal insulation linked to the double coat could lead to a thermal challenge requiring additional peripheral circulation to thermal windows to dissipate the extra heat. To test this hypothesis, we measured the surface temperature of different body regions of captive gentoo penguins (Pygoscelis papua) throughout the moult under constant environmental conditions. The surface temperature of the main body trunk decreased during the initial stages of the moult, suggesting greater thermal insulation. In contrast, the periorbital region, a potential proxy of core temperature in birds, increased during these same early moulting stages. The surface temperature of the bill, flipper and foot (thermal windows) tended to initially increase during the moult, highlighting the likely need for extra heat dissipation in moulting penguins. These results raise questions regarding the thermoregulatory capacities of penguins in the wild during the challenging period of moulting on land in the current context of global warming.

Detection of Mycoplasma spp. in free-living seabirds.

This study aimed to investigate the presence of Mycoplasma spp. and identify the species of mycoplasma isolates obtained from seabirds found on Brazilian coastal beaches. Tracheal and cloacal swab samples were collected from 50 seabirds rescued by three conservation and marine animal rehabilitation centers located in Brazil. The tracheal and cloacal samples were subjected to mycoplasma culture and the isolates were identified through PCR. A "Mollicutes-specific" 16S rRNA PCR reaction was employed for triage. Four species-specific PCR reactions were used to detect Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, or M. gallinarum. The Mollicutes positive and species negative samples were submitted do 16S rRNA sequencing. Eighteen (36%) of 50 seabirds tested positive for mycoplasma by culture. In the PCR for the genus, 28 (56%) of 50 seabirds were positive for Mycoplasma spp., with 13 (26%) detected in the trachea, one (2%) in the cloaca, and 14 (28%) in both sites. In the species-specific PCR, M. gallisepticum was detected in 17.8%, and M. meleagridis in 17.8%. Both species were detected in 14.3%. Of the isolates not characterized at species level, we obtained ten sequences and they were divided into three clusters. The first cluster was closely related to M. meleagridis, the second to M. synoviae, and the third grouped M. tully, M. gallisepticum, and M. imitans. Four and five of nine species of seabirds studied had mycoplasma detected by culture or PCR, respectively. Mycoplasmas were found in the majority of the animals studied, with the highest prevalence proportionally found in Sula leucogaster, and the lowest in Fregata magnificens. The phylogenetic analysis identified Mycoplasma spp. adapted to aquatic birds.

The first report of ovarian torsion causing intracoelomic hemorrhage and subsequent hemorrhagic shock in a captive Humboldt penguin (Spheniscus humboldti).

A 21-year-old captive female Humboldt penguin (Spheniscus humboldti) was in good health until the day before the animal died. However, the animal suddenly exhibited symptoms of vomiting and anorexia, and died in shortly thereafter. The autopsy revealed a blood clot in the abdominal air sac and 280 mL of dark red fluid in the body cavity. The ovary was twisted around a blood vessel. Based on the findings described, it was considered that the cause of death was hypovolemic shock due to massive intracoelomic hemorrhage by vascular collapse resulting from ovarian torsion. This is the first report of ovarian torsion in penguins.

Identification and function analysis of BCL2 in immune response of Pteria penguin.

B-cell lymphoma/leukemia-2 (BCL2), an anti-apoptotic factor in the mitochondrial regulatory pathway of apoptosis, is critically important in immune defenses. In this study, a novel BCL2 gene was characterized from Pteria penguin (P. penguin). The PpBCL2 was 1482 bp long, containing an open reading frame (ORF) of 588 bp encoding 195 amino acids. Four highly conserved BCL-2 homology (BH) domains were found in PpBCL2. Amino acid alignment and phylogenetic tree showed that PpBCL2 had the highest similarity with BCL2 of Crassostrea gigas at 65.24 %. Tissue expression analysis showed that PpBCL2 had high constitutive expression in gill, digestive diverticulum and mantle, and was significantly increased 72 h of Vibrio parahaemolyticus (V. parahaemolyticus) challenge in these immune tissues. Furthermore, PpBCL2 silencing significantly inhibited antimicrobial activity of hemolymph supernatant by 1.4-fold, and significantly reduced the survival rate by 51.7 % at 72 h post infection in P. penguin. These data indicated that PpBCL2 played an important role in immune response of P. penguin against V. parahaemolyticus infection.

A fearful scourge to the penguin colonies: Southern giant petrel (Macronectes giganteus) predation on living Magellanic penguins (Spheniscus magellanicus) may be more common than assumed.

Southern giant petrels (Macronectes giganteus) are important consumers that range across the oceans throughout the southern hemisphere. In Argentina, previous studies have shown they eat primarily pinnipeds and penguins, which they are assumed to scavenge, although there are occasional anecdotes of them attacking living penguins. Here we describe a predation attempt by a trio of southern giant petrels on a molting adult Magellanic penguin (Spheniscus magellanicus) at the large colony at Punta Tombo, Argentina. We relate giant petrel attendance patterns at the colony to the penguins' phenology, showing how giant petrel numbers rise with the increasing prevalence of vulnerable penguins. We suggest that living penguins-both fledglings and adults-may constitute a more seasonally significant proportion of the giant petrel diet than previously assumed, and their capture may represent a specialized predation technique.

Biomechanical analysis of little penguins' underwater locomotion from the free-ranging dive data.

Penguins are proficient swimmers, and their survival depends on their ability to catch prey. The diving behaviour of these fascinating birds should then minimize the associated energy cost. For the first time, the energy cost of penguin dives is computed from the free-ranging dive data, on the basis of an existing biomechanical model. Time-resolved acceleration and depth data collected for 300 dives of little penguins (Eudyptula minor) are specifically employed to compute the bird dive angles and swimming speeds, which are needed for the energy estimate. We find that the numerically obtained energy cost by using the free-ranging dive data is not far from the minimum cost predicted by the model. The outcome, therefore, supports the physical soundness of the chosen model; however, it also suggests that, for closer agreement, one should consider previously neglected effects, such as those due to water currents and those associated with motion unsteadiness. Additionally, from the free-ranging dive data, we calculate hydrodynamic forces and non-dimensional indicators of propulsion performance - Strouhal and Reynolds numbers. The obtained values further confirm that little penguins employ efficient propulsion mechanisms, in agreement with previous investigations.

Pathogenic potential of an environmental Aspergillus fumigatus strain recovered from soil of Pygoscelis papua (Gentoo penguins) colony in Antarctica.

Aspergillus fumigatus is a common opportunistic pathogen in different animals, including birds such as penguins. For the first time, a fungal strain identified as A. fumigatus was isolated from soil in the nests of gentoo penguins, Pygoscelis papua, on Livingston Island, South Shetland Islands (maritime Antarctica). This isolate (A. fumigatus UFMGCB 11829) displayed a series of potentially pathogenic characteristics in vitro. We evaluated its detailed molecular taxonomy and submitted the A. fumigatus UFMGCB 11829 Antarctic strain to in vivo pathogenic modelling. The isolate was confirmed to represent A. fumigatus morphological and phylogenetic analysis showed that it was closely related to A. fumigatus sequences reported from animals, immunosuppressed humans, storage grains, plants and soils. The strain displayed the best mycelial growth and conidia production at 37 ºC; however, it was also able to grow and produce conidia at 15º, demonstrating its capability to survive and colonize penguin nest at least in the summer season in maritime Antarctica. In pathogenicity tests, healthy mice did not showed symptoms of infection; however, 50% lethality was observed in immunosuppressed mice that were inoculated with 106 and 107 spores. Lethality increased to 100% when inoculated with 108 spores. Our data highlight the potential pathogenicity of opportunistic A. fumigatus that may be present in the Antarctic, and the risks of both their further transfer within Antarctica and outwards to other continents, risks which may be exacerbated due global climatic changes.

Capillary Zone Electrophoresis in Humboldt Penguins (Spheniscus humboldti).

Electrophoresis is a useful diagnostic tool for detecting inflammation, including inflammation associated with infectious diseases (eg, aspergillosis in penguins). To our knowledge, reference intervals are not available for plasma proteins via electrophoresis in Humboldt penguins (Spheniscus humboldti). Therefore, preliminary reference intervals for blood plasma proteins measured by capillary zone electrophoresis were calculated for Humboldt penguins from a single zoological collection, and possible differences between the sexes and the ages of the birds were evaluated. Lithium heparinized plasma samples from 39 Humboldt penguins were analyzed. The following sex- and age-independent reference intervals were calculated: total protein 33.8-70.4 g/L, prealbumin 1.9-4.9 g/L, albumin 12.9-31.1 g/L, albumin: globulin ratio 0.7-1.7, α-globulins 4.5-11.6 g/L, ß-globulins 5.6-20.6 g/L, and γ-globulins 2.6-8.4 g/L. Male penguins had a significantly (P = 0.047) higher albumin: globulin ratio and lower percentage of ß-globulins (P = 0.015) in comparison with female penguins. Prealbumin (g/L) significantly (P = 0.021) decreased with increased age of the penguins. These results showed some differences between the sexes and ages of the penguins, which should be considered when interpreting the results. Further studies are needed to determine whether differences in other age groups or seasons exist, and also to evaluate which infectious diseases affect plasma proteins and how the reference values calculated here may deviate in ill penguins.

Retrospective evaluation of Penguin Cold Caps for chemotherapy-induced alopecia.

BACKGROUND: Scalp cooling is an increasingly recognized non-pharmacologic approach to minimize chemotherapy-induced alopecia (CIA). Several commercially available machine-based and manual scalp cooling systems are available; however, literature reports of effectiveness are highly variable. The purpose of this study was to determine real-world tolerability and subjective effectiveness of a manual cold capping system in minimizing CIA across a variety of patient race and hair types. This study was a single-institution review of outcomes from manual cold capping. METHODS: We identified retrospective cohort of adult patients who presented to discuss cold capping between January 14, 2019, and March 31, 2022. Data collected from medical records included demographics, decision to pursue/continue cold capping, diagnoses, chemotherapy regimens, hair characteristics (length, thickness, coarseness, type), and subjective perception of percentage of hair retained. Those with successful vs. unsuccessful cold capping (≥ 50% vs. < 50% of hair retained) were compared based on the patient-level factors of interest. FINDINGS: A total of 100 patients initiated cold capping during the study period, and 95% of them completed cold capping. The majority of patients who started cold capping completed it. The median-reported percentage of hair maintained was 75%, and 82/89 (92.1% of patients) had favorable results, defined as ≥ 50% of hair retained. The only patient-level factor associated with favorable response was chemotherapy regimen, with fewer patients receiving doxorubicin-containing regimens having successful hair retention compared to other chemotherapy types (71.4% successful results vs. 95.7% for those receiving paclitaxel-containing regimens and 96.6% for those receiving docetaxel-containing regimens (p = 0.018). There was no difference in success based on patient race/ethnicity or hair characteristics. INTERPRETATION: The overall effectiveness (92.1%) in this study is consistent to higher than many literature reports. One possible reason for the high success in our cohort is compliance with cold capping protocols, meaning applying the cap in the appropriate manner and wearing the cap for the prescribed durations, which may impact effectiveness.

Spread of antibiotic resistance genes to Antarctica by migratory birds.

Recent studies have highlighted the presence of antibiotic resistance genes (ARGs) in Antarctica, which are typically indicative of human activity. However, these studies have concentrated in the Antarctic Peninsula region, and relatively less is known about ARG prevalence in East Antarctica, where human activity levels are lower compared to the Antarctic Peninsula. In addition, the mechanisms of ARG transmission to Antarctica through natural or anthropogenic pathways remain unclear. In this study, we analyzed the fecal samples of Adélie penguins and South polar skuas by using high-throughput sequencing and microfluidic quantitative PCR to detect potential pathogens and ARGs at their breeding colonies near Syowa Station in East Antarctica. These results revealed the presence of several potential pathogens in the fecal matter of both bird species. However, the HF183 marker, which indicates human fecal contamination, was absent in all samples, as well as seawater sampled near the breeding colonies. This suggests that the human fecal contamination was negligible in our study area. In addition to pathogens, we found a significant number of ARGs and metal resistance genes in the feces of both Adélie penguins and South polar skuas, with higher detection rates in skuas than in penguins. To better understand how these birds acquire and transmit these genes, we analyzed the migratory patterns of Adélie penguins and South polar skuas by geolocator tracking. We found that the skuas migrate to the tropical and subtropical regions of the Indian Ocean during the austral winter. On the other hand, Adélie penguins exhibited a more localized migration pattern, mainly staying within Antarctic waters. Because the Indian Ocean is considered one of the major reservoirs of ARGs, South polar skuas might be exposed to ARGs during their winter migration and transfer these genes to Antarctica.

Living in a challenging environment: Monitoring stress ecology by non-destructive methods in an Antarctic seabird.

How Antarctic species are facing historical and new stressors remains under-surveyed and risks to wildlife are still largely unknown. Adélie penguins Pygoscelis adeliae are well-known bioindicators and sentinels of Antarctic ecosystem changes, a true canary in the coal mine. Immuno-haematological parameters have been proved to detect stress in wild animals, given their rapid physiological response that allows them tracking environmental changes and thus inferring habitat quality. Here, we investigated variation in Erythrocyte Nuclear Abnormalities (ENAs) and White Blood Cells (WBCs) in penguins from three clustered colonies in the Ross Sea, evaluating immuno-haematological parameters according to geography, breeding stage, and individual penguin characteristics such as sex, body condition and nest quality. Concentrations of mercury (Hg) and stable isotopes of carbon and nitrogen (as proxies of the penguin's trophic ecology) were analysed in feathers to investigate the association between stress biomarkers and Hg contamination in Adélie penguins. Colony and breeding stage were not supported as predictors of immuno-haematological parameters. ENAs and WBCs were respectively ∼30 % and ∼20 % higher in male than in female penguins. Body condition influenced WBCs, with penguins in the best condition having a ∼22 % higher level of WBCs than those in the worst condition. Nest position affected the proportion of micronuclei (MNs), with inner-nesting penguins having more than three times the proportion of MNs than penguins nesting in peripheral positions. Heterophils:Lymphocytes (H:L) ratio was not affected by any of the above predictors. Multiple factors acting as stressors are expected to increase prominently in Antarctic wildlife in the near future, therefore extensive monitoring aimed to assess the health status of penguin populations is mandatory.

Ancient and Modern Genomes Reveal Microsatellites Maintain a Dynamic Equilibrium Through Deep Time.

Microsatellites are widely used in population genetics, but their evolutionary dynamics remain poorly understood. It is unclear whether microsatellite loci drift in length over time. This is important because the mutation processes that underlie these important genetic markers are central to the evolutionary models that employ microsatellites. We identify more than 27 million microsatellites using a novel and unique dataset of modern and ancient Adélie penguin genomes along with data from 63 published chordate genomes. We investigate microsatellite evolutionary dynamics over 2 timescales: one based on Adélie penguin samples dating to ∼46.5 ka and the other dating to the diversification of chordates aged more than 500 Ma. We show that the process of microsatellite allele length evolution is at dynamic equilibrium; while there is length polymorphism among individuals, the length distribution for a given locus remains stable. Many microsatellites persist over very long timescales, particularly in exons and regulatory sequences. These often retain length variability, suggesting that they may play a role in maintaining phenotypic variation within populations.

Evaluation of Metal Partitioning across Humboldt Penguin (Spheniscus humboldti) Egg Components.

Humboldt Penguin (Spheniscus humboldti) population declines are attributable to several multifaceted anthropogenic impacts. At present, the exposure of Humboldt Penguins to high concentrations of heavy metals in the marine environment is a preeminent concern, due to mining along the Peruvian coast near key rookery sites. Metal and selenium concentrations were determined in eggs collected from September 2020 to April 2021 from a managed-care penguin population at the Brookfield Zoo to establish reference values for health indices conducted on wild populations. Concentrations of 16 elements, with emphasis on those found in mine efflux-arsenic, cadmium, copper, lead, mercury, selenium, and zinc-were assessed via inductively coupled plasma mass spectrometry in yolk, albumen, and eggshell. Data analyses indicate a clear delineation between egg constituents, with lipid-rich yolk displaying notably higher concentrations (µg/g) of arsenic (0.20 ± 0.064), chromium (0.086 ± 0.03), cobalt (0.01 ± 0.003), iron (238.65 ± 54.72), lead (0.32 ± 0.97), manganese (2.71 ± 0.66), molybdenum (0.57 ± 0.14), tin (3.29 ± 0.99), and zinc (64.03 ± 13.01) than other components (albumen and eggshell). These data confirm that heavy metals are partitioned differently across Humboldt Penguin egg components, which provides insight into the potential connection between embryonic nutrient source contamination and subsequent chick viability.

Sex-specific recruitment rates contribute to male-biased sex ratio in Adélie penguins.

Sex-related differences in vital rates that drive population change reflect the basic life history of a species. However, for visually monomorphic bird species, determining the effect of sex on demographics can be a challenge. In this study, we investigated the effect of sex on apparent survival, recruitment, and breeding propensity in the Adélie penguin (Pygoscelis adeliae), a monochromatic, slightly size dimorphic species with known age, known sex, and known breeding history data collected during 1996-2019 (n = 2127 birds) from three breeding colonies on Ross Island, Antarctica. Using a multistate capture-mark-recapture maximum-likelihood model, we estimated apparent survival (S^), recapture (resighting) probability (p^), and the probability of transitioning among breeding states and moving between colonies (ψ^; colony-specific non-juvenile pre-breeders, breeders, and non-breeders). Survival rate varied by breeding status and colony, but not sex, and pre-breeders had higher survival rates than breeders and non-breeders. Females had a higher probability of recruiting into the breeding population each year and may enter the breeding pool at younger ages. In contrast, both sexes had the same probability of breeding from year to year once they had recruited. Although we detected no direct sex effects on survival, the variation in recruitment probability and age-at-first reproduction, along with lower survival rates of breeders compared to pre-breeders, likely leads to shorter lifespans for females. This is supported by our findings of a male-biased mean adult sex ratio (ASR) of 1.4 males for every female (x^ proportion of males = 0.57, SD = 0.07) across all colonies and years in this metapopulation. Our study illustrates how important it can be to disentangle sex-related variation in population vital rates, particularly for species with complex life histories and demographic dynamics.

Increased Contribution of Circumpolar Deep Water Upwelling to Methylmercury in the Upper Ocean around Antarctica: Evidence from Mercury Isotopes in the Ornithogenic Sediments.

Upwelling plays a pivotal role in supplying methylmercury (MeHg) to the upper oceans, contributing to the bioaccumulation of MeHg in the marine food web. However, the influence of the upwelling of Circumpolar Deep Water (CDW), the most voluminous water mass in the Southern Ocean, on the MeHg cycle in the surrounding oceans and marine biota of Antarctica remains unclear. Here, we study the mercury (Hg) isotopes in an ornithogenic sedimentary profile strongly influenced by penguin activity on Ross Island, Antarctica. Results indicate that penguin guano is the primary source of Hg in the sediments, and the mass-independent isotope fractionation of Hg (represented by Δ199Hg) can provide insights on the source of marine MeHg accumulated by penguin. The Δ199Hg in the sediments shows a significant decrease at ∼1550 CE, which is primarily attributed to the enhanced upwelling of CDW that brought more MeHg with lower Δ199Hg from the deeper seawater to the upper ocean. We estimate that the contribution of MeHg from the deeper seawater may reach more than 38% in order to explain the decline in Δ199Hg at ∼1550 CE. Moreover, we found that the intensified upwelling may have increased the MeHg exposure for marine organisms, highlighting the importance of CDW upwelling on the MeHg cycle in Antarctic coastal ecosystems.

Corynebacterium mendelii sp. nov., a novel bacterium isolated from Adélie penguin oral cavity.

The taxonomic status of strain P5891T, isolated from an Adélie penguin beak swab, was investigated. Based on the 16S rRNA gene sequence, the strain was identified as a potentially novel Corynebacterium species, with the highest sequence similarities to Corynebacterium rouxii FRC0190T (96.7 %) and Corynebacterium epidermidicanis DSM 45586T (96.6 %). The average nucleotide identity values between strain P5891T and C. rouxii FRC0190T and C. epidermidicanis DSM 45586T were 68.2 and 69.2 %, respectively. The digital DNA-DNA hybridization values between strain P5891T and C. rouxii FRC0190T and C. epidermidicanis DSM 45586T were 23.7 and 21.4 %, respectively. Phylogenetic trees based on the 16S rRNA sequence placed strain P5891T in a separate branch with Corynebacterium canis 1170T and Corynebacterium freiburgense 1045T, while a phylogenomic tree based on the Corynebacterium species core genome placed the strain next to Corynebacterium choanae 200CHT. Extensive phenotyping and genomic analyses clearly confirmed that strain P5891T represents a novel species of the genus Corynebacterium, for which the name Corynebacterium mendelii sp. nov. is proposed, with the type strain P5891T (=CCM 8862T=LMG 31627T).

Co-administration of the prebiotic 1-kestose and the paraprobiotic Lactiplantibacillus plantarum FM8 in magellanic penguins promotes the activity of intestinal Lactobacillaceae and reduces the plc gene levels encoding Clostridium perfringens toxin.

Despite the well-known potential health benefits of prebiotics and non-viable probiotics (paraprobiotics) in various animal species, research regarding their use in penguins is scarce. Our study aimed to investigate the impact of a combined administration of prebiotics and paraprobiotics (referred to here as "parasynbiotics") on the gut microbiome and overall health of Magellanic penguins (Spheniscus magellanicus). The parasynbiotics consisted of 1-kestose, which is a fructooligosaccharide comprising sucrose and fructose, and heat-killed Lactiplantibacillus plantarum FM8, isolated from pickled vegetables. It was administered to eight penguins aged <3 years (Young-group) and nine penguins aged >17 years (Adult-group) for 8 weeks. Results from 16S rRNA sequencing revealed that compared to baseline, parasynbiotic administration significantly decreased the relative abundance of intestinal Clostridiaceae_222000 in both groups and significantly increased that of Lactobacillaceae in the Young-group. Quantitative real-time polymerase chain reaction revealed a significant decrease in the plc gene levels encoding alpha-toxin of Clostridium perfringens in the Young-group after parasynbiotic administration (P=0.0078). In the Young-group, parasynbiotic administration significantly increased the plasma levels of total alpha-globulin (P=0.0234), which is associated with inflammatory responses. Furthermore, exposure of dendritic cells to heat-killed L. plantarum FM8 promoted the secretion of interleukin 10, a major anti-inflammatory cytokine. Overall, parasynbiotic administration enhanced the activity of gut Lactobacillaceae, decreased the levels of C. perfringens and its toxin encoding plc gene, and reduced inflammatory response in penguins. These results provide novel insights into the potential benefits of parasynbiotics for improving penguin health.

Usefulness of combining computed tomography and air sac fluid examination to rule out aspergillosis: case study in two gentoo penguins (Pygoscelis papua) with respiratory clinical signs.

Pulmonary aspergillosis occurring in captive penguins living in zoos and aquariums is a fatal disease owing to its high mortality rate. On conducting computed tomography, two gentoo penguins (Pygoscelis papua) with respiratory clinical signs that were housed at an aquarium in Hokkaido, Japan were found to have a certain amount of fluid in their air sacs. This fluid was collected and cultured for bacteria and fungi, the results of which both came back negative. These results enabled us to rule out bacterial infection or aspergillosis and supported our decision not to administer antibacterial and antifungal drugs. Overall, the combination of computed tomography and air sac fluid examination was useful for ruling out bacterial infection or aspergillosis in penguins with respiratory clinical signs.

The Effects of Critical Care Nutrition on Weight Gain in African Penguin (Spheniscus demersus) Chicks.

Nutritional support in malnourished animals is an essential aspect of wildlife rehabilitation; this support is especially relevant when providing lifesaving nutrition to endangered species such as the African penguin (Spheniscus demersus). This study investigated the short-term effects of a commercially available, semi-elemental, critical care diet compared with a hand-made fish formula. Twenty-one African penguin chicks were selected on admission to the Southern African Foundation for the Conservation of Costal Birds in Cape Town, South Africa, in November 2015. Initial assessment included body weight, a full clinical exam, white blood cell count, packed cell volume, and total plasma protein. Ten animals received the commercial critical care diet, whereas a control group of 11 animals were fed hand-made formula for the 2-week study period. All animals were weighed daily and blood sampling was repeated after 14 days. The median weight of both groups increased significantly over 14 days (critical care diet χ2 = 10.1, P = 0.002; control χ2 = 7.4, P = 0.006). The difference was not significant between the groups for start weight (χ2 = 0.1, P = 0.725) or end weight (χ2 = 0, P = 1.000) and was not significantly different in the change over time for either absolute numbers (χ2 = 1.7, P = 0.193) or percent gain (χ2 = 0.8, P = 0.36). The values for packed cell volume, total plasma protein, and white blood cell count increased in all animals after the 14-day study period was complete. On the basis of the results of this study, it was determined that the differing diets led to similar weight gain.

Phylogenetic Analyses of Lizards from the Chilean Humboldt Archipelago Reveal a New Species for the Chañaral Island (Squamata: Liolaemidae).

The Humboldt Archipelago, situated on Chile's north-central coast, is renowned for its exceptional biodiversity. However, lizards of the Liolaemus genus are a particularly understudied group in this archipelago. Liolaemus genus is divided into two clades: chiliensis and nigromaculatus. Within the nigromaculatus clade the zapallarensis group is restricted to the semi-arid and arid coastal habitats of the Atacama Desert in north-central Chile. While it has been reported that lizards from the zapallarensis group inhabit various islands within the Humboldt Archipelago, there has been limited knowledge regarding their specific species identification. To identify the lizard species inhabiting these islands, we conducted phylogenetic analyses using a mitochondrial gene and examined morphological characteristics. Our findings reveal that lizards from the Damas, Choros, and Gaviota islands belong to Liolaemus silvai. In contrast, the lizards on Chañaral Island form a distinct and previously unrecognised group, clearly distinguishable from Liolaemus silvai. In conclusion, our study not only confirms the presence of L. silvai on the Damas, Choros, and Gaviota islands but also describes a new lizard species on Chañaral Island named Liolaemus carezzae sp. nov. These findings contribute valuable insights into the biodiversity of these islands and introduce a newly discovered endemic taxon to the region, enriching our understanding of Chile's unique island ecosystems.