Stock identification of Kawakawa Euthynnus affinis (Cantor, 1849) from Peninsular Malaysia using discriminant analysis

Small epipelagic and migratory, Eutynnus affinis (kawakawa) is one of the commercially significant tunas of Indo-Pacific’s tropical and subtropical waters. Consequently, successful management must ensure its sustainability. Unfortunately, the management and stock structure of certain migratory species in the area are not clear. The current study aimed to discriminate the E. affinis through body shape variations and to evaluate the variations among seven populations of E. affinis. A total of 114 individuals of E. affinis collected from two main geographic area, Straits of Malacca and South China Sea. Multivariate analyses, such as discriminant function analyses (DFA) of 12 morphometric characters was carried out to discriminate seven populations of E. affinis. The results revealed there is a significant variation among the body shape and seven populations of E. affinis. The average shapes of populations from Terengganu, Kelantan, and Johor were approximately similar to each other. In contrast, the average shapes of populations from Selangor were separated. This present study is the first report using morphometric method conducted on E. affinis from Peninsular Malaysian waters.

Sexual dimorphism in morphology and plumage of endangered Yuma Ridgway’s Rails: a model for documenting sex

Many applications in wildlife management require knowledge of the sex of individual animals. The Yuma Ridgway’s Rail Rallus obsoletus yumanensis is an endangered marsh bird with monomorphic plumage and secretive behaviors, thereby complicating sex determination in field studies. We collected morphometric measurements from 270 adult Yuma Ridgway’s Rails and quantified the plumage and mandible color of 91 of those individuals throughout their geographic range to evaluate inter-sexual differences in morphology and coloration. We genetically sexed a subset of adult Yuma Ridgway’s Rails ( N =101) and used these individuals to determine the optimal combination of measurements (based on discriminant function analyses) to distinguish between sexes. Males averaged significantly larger than females in all measurements and the optimal discriminant function contained whole-leg, culmen, and tail measurements and classified correctly 97.8% (95% CI: 92.5-100.0%) of genetically sexed individuals. We used two additional functions that correctly classified ≥95.5% of genetically sexed Yuma Ridgway’s Rails to assign sex to individuals with missing measurements. These simple models provide managers and researchers with a practical tool to determine the sex of Yuma Ridgway’s Rails based on morphometric measurements. Although color measurements were not in the most accurate discriminant functions, we quantified subtle inter-sexual differences in the color of mandibles and greater coverts of Yuma Ridgway’s Rails. These results document sex-specific patterns in coloration that allow future researchers to test hypotheses to determine the mechanisms underlying sex-based differences in plumage coloration.

Morphometric Sex Identification of Nestling and Free-Flying Tasmanian Wedge-Tailed Eagles (Aquila audax fleayi)

ABSTRACT The endangered Tasmanian Wedge-tailed Eagle (Aquila audax fleayi) is the focus of continued research and conservation efforts. A tool for accurate and efficient identification of the sex of individuals would be a valuable aid to research and management. However, plumages are monomorphic between the sexes, making sex identification difficult without molecular analyses. Our aim was to assess whether Tasmanian Wedge-tailed Eagles of different age classes could be sexed accurately using morphological measurements. We took measurements of 25 live late-stage eagle nestlings and 108 carcasses of free-flying birds found opportunistically throughout Tasmania. Sex of all individuals was confirmed via genetic analyses. Free-flying birds were larger than nestlings; thus, we used age-specific statistical tools to distinguish the sexes. For both nestlings and free-flying birds, females were significantly larger than males, but overlap between the sexes prevented accurate sex identification using any single measurement. We used stepwise linear discriminant function analyses to select morphometric measurements necessary for accurate sex identification. Free-flying birds could be sexed with 97.6% accuracy using a combination of measurements of the forearm length, tarsus width (i.e., lateromedial width), and hallux length. Late-stage nestlings (9–10 wk old) could be sexed with 95.4% accuracy using measurements of the hallux width (i.e., lateromedial width), hallux breadth (i.e., anteroposterior width of hallux), and tarsus breadth (i.e., anteroposterior width of the tarsometatarsus at the narrowest point). The discriminate functions we present also allow the identification of sex in cases where morphological sex identification may be in doubt and molecular analyses should be prioritized. These equations provide a valuable research tool for studies of sexual differences in behavior and causes of mortality of this endangered subspecies.

Truss network based morphometric and meristic variations among south-western populations of Macrognathus aculeatus in Bangladesh

Aim: Landmark-based truss network system was applied to examine the morphometric and meristic differences among four different populaces of Macrognathus aculeatus namely; Dhakuriabeel, Jashore (DBJ); Arial Kha River, Madaripur (AKRM); Nabaganga River, Jhenaidah (NRJ); Kopotakkha River, Jashore (KRJ) in Bangladesh. Methodology: Completely 80 samples of M. aculeatus were collected (20 individuals from each population) for this study. Six meristic characters, 6 morphometric characters and 15 truss-based morphometric characters were measured for one-way analysis of variance (ANOVA) and Tukey-HSD post hoc test. Discriminant function analyses were also performed by using morphometric and truss-based morphometric characters to detect potential characters responsible for population separation. Results: Completely 80 samples of M. aculeatus were collected (20 individuals from each population) for this study. Six meristic characters, 6 morphometric characters and 15 truss-based morphometric characters were measured for one-way analysis of variance (ANOVA) and Tukey-HSD post hoc test. Discriminant function analyses were also performed by using morphometric and truss-based morphometric characters to detect potential characters responsible for population separation. Interpretation: The baseline information derived from the present study would be useful for appropriate conservation of M. aculeatus populations as well as for the researchers for further investigation.

Ecomorphology and ecology of the grassland specialist, Rusingoryx atopocranion (Artiodactyla: Bovidae), from the late Pleistocene of western Kenya

Rusingoryx atopocranion is an extinct alcelaphin bovid from the late Pleistocene of Kenya, known for its distinctive hollow nasal crest. A bonebed of R. atopocranion from the Lake Victoria Basin provides a unique opportunity to examine the nearly complete postcranial ecomorphology of an extinct species, and yields data that are important to studying paleoenvironments and human-environment interaction. With a comparative sample of extant African bovids, we used discriminant function analyses to develop statistical ecomorphological models for 18 skeletal elements and element portions. Forelimb and hindlimb element models overwhelmingly predict that R. atopocranion was an open-adapted taxon. However, the phalanges of Rusingoryx are remarkably short relative to their breadth, a morphology outside the range of extant African bovids, which we interpret as an extreme open-habitat adaptation. It follows that even recently extinct fossil bovids can differ in important morphological ways relative to their extant counterparts, particularly if they have novel adaptations for past environments. This unusual phalanx morphology (in combination with other skeletal indications), mesowear, and dental enamel stable isotopes, demonstrate that Rusingoryx was a grassland specialist. Together, these data are consistent with independent geological and paleontological evidence for increased aridity and expanded grassland habitats across the Lake Victoria Basin.

Discriminant Function Analyses: Classifying Drugs/Violence Victimization Typologies Among Incarcerated Rural Women

This study examined the relationship between drug use and violence victimization among incarcerated women in Appalachian Kentucky. The purpose of this study was to test the utility of Goldstein’s tripartite conceptual framework among rural incarcerated women, by examining whether distinct drugs/violence nexus groups could be classified based on psychopharmacological, economic-compulsive, and systemic factors. This study used secondary data from a National Institute on Drug Abuse (NIDA)-funded grant focused on risk reduction among high-risk incarcerated women in Appalachia ( N = 400). Predicted drugs/violence groups were developed using a series of discriminant function analyses. The data yielded three statistically significant discriminant models. Findings of the classified groupings indicated support for three distinct drugs/violence victimization subgroups. The psychopharmacological group showed the greatest prevalence ( n = 181; Wilks’s λ = .389, F = 3.94, p < .001), followed by the economic-compulsive group ( n = 77; Wilks’s λ = .584, F = 11.86, p < .001) and systemic group ( n = 55) significant (Wilks’s λ = .994, F = 2.247, p < .035). To date, this is the first study to report a relationship between systemic violence victimization among rural communities. These findings could offer novel considerations for theory development and implications for clinical practice regarding the drug-related risks for violence victimization among rural incarcerated women.

Morphological variation of the widely distributed genus Stenocorse Marsh, 1968 (Hymenoptera: Braconidae: Doryctinae)

Stenocorse is a monotypic genus with wide distribution and a large range of beetle hosts. We analyzed the morphological variation of 346 specimens from the USA south to Brasil. We studied 15 morphometric and 30 discrete characters using principal component (PCA) and discriminant function analyses (DFA) to assess character informativeness and the influence of geographic distribution and host source to detect differentiation. Mexican samples were studied according to location and biogeographic provinces. Specimens from Colombia were studied according to the plant where the host was recorded. Three measurements show group differentiation whereas four were redundant. Three groups of individuals were supported by continuous and discrete characters: one found in the USA, Mexico, Nicaragua and Costa Rica, a second from Mexico, and a third from Colombia and Brazil. These groups showed poor agreement with the differentiation of its common beetle host populations. This could be a consequence of the large number of sympatric host species feeding on a large number of plant species. This research shed light on other sources of evidence for building a sound taxonomy for Stenocorse.

Trash or treasure? Use of sagittal otoliths partially composed of vaterite for hatchery stock discrimination in steelhead

Sagittal otoliths are normally deposited as the CaCO3 polymorph aragonite; however, a proportion of otoliths transitions to vaterite during growth. This transition can complicate otolith chemistry analyses, as differences in the crystalline structure (aragonite or vaterite) of otoliths causes variation in otolith chemistry signatures. To address this issue, we introduce a method to utilize sagittal otoliths partially composed of vaterite for stock discrimination. Using this method, we determined the hatchery origins of yearlings from five Lake Erie hatcheries by using Ba, Mg, Mn, and Sr concentrations in vaterite sections of steelhead (Oncorhynchus mykiss) otoliths. We then compared the classification accuracy of our vaterite method with a method in which otoliths composed entirely of aragonite were used. Overall, quadratic discriminant function analyses revealed similar classification success when elemental concentrations from vaterite (95% accuracy) and aragonite (94% accuracy) otolith regions were used. The methods introduced here could likely be used for other fish species that have otoliths that transition to vaterite as long as an adequate number of juvenile fish are available to develop vaterite otolith chemistry signatures.

Predicting patterns of service utilization within children’s mental health agencies

Background Some children with mental health (MH) problems have been found to receive ongoing care, either continuously or episodically. We sought to replicate patterns of MH service use over extended time periods, and test predictors of these patterns. Methods Latent class analyses were applied to 4 years of visit data from five MH agencies and nearly 6000 children, 4- to 13-years-old at their first visit. Results Five patterns of service use were identified, replicating previous findings. Overall, 14% of cases had two or more episodes of care and 23% were involved for more than 2 years. Most children (53%) were seen for just a few visits within a few months. Two patterns represented cases with two or more episodes of care spanning multiple years. In the two remaining patterns, children tended to have just one episode of care, but the number of sessions and length of involvement varied. Using discriminant function analyses, we were able to predict with just over 50% accuracy children’s pattern of service use. Severe externalizing behaviors, high impairment, and high family burden predicted service use patterns with long durations of involvement and frequent visits. Conclusions Optimal treatment approaches for children seen for repeated episodes of care or for care lasting multiple years need to be developed. Children with the highest level of need (severe pathology, impairment, and burden) are probably best served by providing high intensity services at the start of care.

High frequency audible calls in northern birch mice Sicista betulina in response to handling: effects of individuality, sex and body mass on the acoustics

Objectives This is the first study of the sonic and ultrasonic vocalization in a Dipodidae rodent. For the small-sized quadrupedal northern birch mouse Sicista betulina, phylogenetically related to the bipedal jerboas (Dipodidae), we report null results for ultrasonic vocalization and investigate the acoustic cues to individual identity, sex and body size in the discomfort-related high-frequency tonal sonic calls. Results We used a parallel audio recording in the sonic and ultrasonic ranges during weighting adult northern birch mice before the scheduled hibernation in captivity. The sonic (audible) high-frequency tonal calls (ranging from 6.21 to 9.86 kHz) were presented in all individuals (7 males and 4 females). The ultrasonic calls lacked in the recordings. Two-way nested ANOVA revealed the effects of caller individual identity on all 10 measured acoustic variables and the effects of sex on four out of 10 measured acoustic variables. Discriminant function analyses with 10 acoustic variables included in the analysis showed 85.5% correct assignment of calls to individual and 79.7% correct assignment of calls to sex; both values significantly exceeded the random values (23.1% and 54.3%, respectively) calculated with randomization procedure. Body mass did not differ between sexes and did not correlate significantly with the acoustic variables.