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Abstract Background The scientific literature contains many examples where DNA sequence analyses have been used to provide definitive answers to phylogenetic problems that traditional (non-DNA based) approaches alone have failed to resolve. One notable example concerns the rhinoceroses, a group for which several contradictory phylogenies were proposed on the basis of morphology, then apparently resolved using mitochondrial DNA fragments. Results In this study we report the first complete mitochondrial genome sequences of the extinct ice-age woolly rhinoceros (Coelodonta antiquitatis), and the threatened Javan (Rhinoceros sondaicus), Sumatran (Dicerorhinus sumatrensis), and black (Diceros bicornis) rhinoceroses. In combination with the previously published mitochondrial genomes of the white (Ceratotherium simum) and Indian (Rhinoceros unicornis) rhinoceroses, this data set putatively enables reconstruction of the rhinoceros phylogeny. While the six species cluster into three strongly supported sister-pairings: (i) The black/white, (ii) the woolly/Sumatran, and (iii) the Javan/Indian, resolution of the higher-level relationships has no statistical support. The phylogenetic signal from individual genes is highly diffuse, with mixed topological support from different genes. Furthermore, the choice of outgroup (horse vs tapir) has considerable effect on reconstruction of the phylogeny. The lack of resolution is suggestive of a hard polytomy at the base of crown-group Rhinocerotidae, and this is supported by an investigation of the relative branch lengths. Conclusion Satisfactory resolution of the rhinoceros phylogeny may not be achievable without additional analyses of substantial amounts of nuclear DNA. This study provides a compelling demonstration that, in spite of substantial sequence length, there are significant limitations with single-locus phylogenetics. We expect further examples of this to appear as next-generation, large-scale sequencing of complete mitochondrial genomes becomes commonplace in evolutionary studies. "The human factor in classification is nowhere more evident than in dealing with this superfamily (Rhinocerotoidea)." G. G. Simpson (1945)

Nonbreeding white rhino bulls are traditionally housed individually in zoos, but space limitations require the exploration of alternative techniques. There are no studies of group-housed bulls, and the feasibility of managing a bachelor group is unknown. Six bulls (two bulls each of 3-, 5-, and 8-yr-olds) in a 3.1 ha enclosure were observed for 30 min each 2×/wk for 20–31 wks. The 3-yr-olds were relocated after the first 20 weeks. Rhino location, nearest neighbor, aggressive behaviors, and dominance interactions were recorded. There was no evidence of habitat spatial segregation. The 3- and 5-yr-olds grouped together by age; 8-yr-olds did not associate as much as younger rhinos. Aggressive vocalizations and physical aggression were infrequent (range 0–1.5/h/bull and 0–1/h/bull, respectively). Eight-year-olds displayed and received aggressive vocalizations the most; three-year-olds displayed and received physical aggression the most. After the 3-yr-olds were removed, the habitat usage and social proximity of the remaining bulls did not change. Aggressive behaviors increased, but vocalizations (range 0.18–3.1/h/bull) remained more frequent than physical aggression (range 0.18–0.73/h/bull). The highest-ranking 8-yr-old engaged in physical altercations the least. The bulls shared space, and the use of vocalizations more than physical aggression deterred injury. These findings indicate that bachelor group management is feasible in a large enclosure with young bulls. [ABSTRACT FROM AUTHOR]

More than 50% of caudates are threatened with extinction and are in need of ex-situ breeding programs to support conservation efforts and species recovery. Unfortunately, many salamander populations under human care can experience reproductive failure, primarily due to missing environmental cues necessary for breeding. Assisted reproductive technologies (ARTs) are a useful suite of techniques for overcoming or bypassing these missing environmental cues to promote breeding. Exogenous hormones are used to stimulate natural breeding behaviors or gamete expression for in-vitro fertilization or biobanking and are typically administered intramuscularly in caudates. While effective, intramuscular injection is risky to perform in smaller-bodied animals, resulting in health and welfare risks. This research investigated the spermiation response to hormone administration through a non-invasive oral bioencapsulation route using the tiger salamander (Ambystoma tigrinum) as a model species. Male salamanders were randomly rotated six weeks apart through four treatments (n = 11 males/treatment) in which animals received a resolving dose of gonadotropin-releasing hormone (GnRH) as follows: (1) Prime-Only (0.0 μg/g); (2) Low (0.25 μg/g); (3) Medium (1.0 μg/g); and (4) High (2.0 μg/g). All males were given a GnRH priming dose (0.25 μg/g) 24 hours prior to the resolving dose. Exogenous hormone was delivered inside of a cricket (Gryllodes sigillatus) that was presented as a food item by tweezers. Sperm samples were collected at 1, 3, 6, 9, 12, and 24 hours after the resolving dose and analyzed for quantity and quality. For all treatments, sperm concentration was produced in an episodic pattern over time. The Prime-Only treatment had a lower (p < 0.05) percent of sperm exhibiting normal morphology compared to treatments utilizing a resolving dose of GnRH. Overall, oral administration of GnRH is a feasible route of inducing spermiation in salamanders, yielding sperm of sufficient quantity and quality for in-vitro fertilization and biobanking efforts. [ABSTRACT FROM AUTHOR]

A consequence of the poaching crisis is that managed rhinoceros populations are increasingly important for species conservation. However, black rhinoceroses (BR; Diceros bicornis) and Sumatran rhinoceroses (SR; Dicerorhinus Sumatrensis) in human care often store excessive iron in organ tissues, a condition termed iron overload disorder (IOD). IOD research is impeded by the challenge of accurately monitoring body iron load in living rhinoceroses. The goals of this study were to (i) determine if labile plasma iron (LPI) is an accurate IOD biomarker and (ii) identify factors associated with iron-independent serum oxidative reduction potential (ORP). Serum (106 samples) from SRs (n  = 8), BRs (n  = 28), white rhinoceros (n  = 24) and greater one-horned rhinoceros (GOH; n  = 16) was analysed for LPI. Samples from all four species tested positive for LPI, and a higher proportion of GOH rhinoceros samples were LPI positive compared with those of the other three species (P  < 0.05). In SRs, the only LPI-positive samples were those from individuals clinically ill with IOD, but samples from outwardly healthy individuals of the other three species were LPI positive. Serum ORP was lower in SRs compared with that in the other three species (P  < 0.001), and iron chelation only reduced ORP in the GOH species (P  < 0.01; ~5%). Serum ORP sex bias was revealed in three species with males exhibiting higher ORP than females (P  < 0.001), the exception being the SR in which ORP was low for both sexes. ORP was not associated with age or serum iron concentrations (P  ≥ 0.05), but was positively correlated with ferritin (P  < 0.01). The disconnect between LPI and IOD was unanticipated, and LPI cannot be recommended as a biomarker of advanced rhino IOD. However, data provide valuable insight into the complex puzzle of rhinoceros IOD. [ABSTRACT FROM AUTHOR]

Urinary hormone analysis was conducted on two adult female Indian rhinoceroses ( Rhinoceros unicornis) that exhibited minimal or no estrual behaviors traditionally used to time breeding. Urine was collected throughout two consecutive estrous cycles to establish preliminary data on each individual's pattern and concentration of estrogen conjugates (EC) and progesterone metabolites (PdG) during follicular and luteal phases. Following preliminary endocrine analysis, urine samples were shipped on a frequent basis to verify when each female was off baseline in EC. Estrus and breeding dates were then predicted. Females were introduced to fresh male rhinoceros fecal samples daily throughout the follicular phase to potentially stimulate estrous behaviors. Despite successful assessment of follicular phase dynamics, females sometimes failed to exhibit estrus. Both females conceived following mating introductions that were timed using hormone analysis. Pregnancy was diagnosed either by endocrine analysis or rectal ultrasonography. Progestational support (altrenogest) occurred after pregnancy confirmation and varied for each female (21 and 66 days post-breeding). One female experienced early pregnancy loss and the other successfully completed a term pregnancy. These results demonstrate that a science based management strategy that relies on urinary biomarkers of ovarian function can facilitate naturally breeding captive Indian rhinoceroses. Zoo Biol. 33:83-88, 2014. © 2013 Wiley Periodicals Inc. [ABSTRACT FROM AUTHOR]