Morphological, mitochondrial, and nuclear phylogenomic data were combined to address phylogenetic and species delimitation questions in cave-limited Cicurina spiders from central Texas. Special effort was focused on specimens and cave locations in the San Antonio region (Bexar County), home to four eyeless species listed as US Federally Endangered. Sequence capture experiments resulted in the recovery of ~200–400 homologous ultra-conserved element (UCE) nuclear loci across taxa, and nearly complete COI mitochondrial DNA sequences from the same set of individuals. Some of these nuclear and mitochondrial sequences were recovered from “standard” museum specimens without special preservation of DNA material, including museum specimens preserved in the 1990s. Multiple phylogenetic analyses of the UCE data agree in the recovery of two major lineages of eyeless Cicurina in Texas. These lineages also differ in mitochondrial clade membership, female genitalic morphology, degree of troglomorphy (as measured by relative leg length), and are mostly allopatric across much of Texas. Rare sympatry was confirmed in Bexar County, where members of the two major clades sometimes co-exist in the same karst feature. Both nuclear phylogenomic and mitochondrial data indicate the existence of undescribed species from the San Antonio region, although further sampling and collection of adult specimens is needed to explicitly test these hypotheses. Our data support the two following species synonymies (Cicurina venii Gertsch, 1992 = Cicurina madla Gertsch, 1992; Cicurina loftini Cokendolpher, 2004 = Cicurina vespera Gertsch, 1992), formally proposed here. Overall, our taxonomy-focused research has many important conservation implications, and again highlights the fundamental importance of robust taxonomy in conservation research.
The spectrum of disease that affects the temporomandibular joint (TMJ) can be varied. To differentiate among the diseases that cause pain and dysfunction, an intimate knowledge of the anatomy, physiology, and pathology of this region is necessary. Due to the joint's complex anatomy and relationship to the skin, it has been difficult to image in the past. Magnetic resonance imaging is ideally suited for visualizing TMJ because of its superb contrast resolution when imaging soft tissues. Magnetic resonance imaging allows simultaneous bilateral visualization of both joints. The ability to noninvasively resolve anatomic detail can be performed easily and quickly using magnetic resonance imaging. The development of magnetic resonance imaging has greatly aided the diagnosis of TMJ disorders. An understanding of TMJ anatomy and pathogenesis of TMJ pain is crucial for interpretation of magnetic resonance imaging and subsequent treatment.
We assessed differences in the otolith microchemistry of koi carp, a colour variant of the invasive common carp Cyprinus carpio, at various locations in the Waikato region of New Zealand. Although koi carp are abundant here, little is known about where and in what habitats they breed. We investigated the feasibility of determining the natal habitats of adult koi carp (in the Waikato River, selected tributaries, and riverine lakes in the catchment) using otolith elemental signatures and employing laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Differences in elemental concentrations in water among the sites indicated that variation in otolith microchemistry was likely. Ratios of manganese (Mn), rubidium (Rb), strontium (Sr), and barium (Ba) to calcium (Ca) in otolith edges differed significantly among the sites, and Sr:Ca in the water and otoliths was positively correlated. A discriminant function analysis using Rb, Sr, and Ba accurately classified the otolith edge signatures of koi carp from some locations, but the otolith signatures of koi carp caught from adjacent locations were often indistinguishable. This suggests that our results could have been confounded by either (1) recent movement of koi carp or (2) a lack of differences in water chemistry among sites. Taken together, these results demonstrate that otolith microchemistry can be used to test retrospectively for koi carp migration between sites on a broad scale in the Waikato region, but fine-scale movements may not be detectable.
We characterised seasonal and ontogenetic changes in diet and prey energy density of rainbow trout (Oncorhynchus mykiss) in Lake Rotoiti, New Zealand, to better understand the prey requirements of trout in central North Island lakes. Common smelt (Retropinna retropinna) was the dominant prey item of rainbow trout larger than 200 mm (77.8% of diet by weight), followed by kō ura (freshwater crayfish Paranephrops planifrons; 6.3%), common bully (Gobiomorphus cotidianus; 5.5%), and kō aro (Galaxias brevipinnis; 3.4%). Juvenile rainbow trout (B200 mm) consumed amphipods, aquatic and terrestrial insects, oligochaetes, tanaid shrimps, and smelt. Trout consumed kō aro only in autumn and winter; consumption of other species did not vary seasonally. The maximum size of smelt consumed increased with increasing trout size, but trout continued to consume small smelt even as large adults. Consumption of larger prey items (kō aro and kō ura) also increased with increasing trout size. This study indicates the importance of smelt for sustaining rainbow trout populations, as predation on other species was relatively low. These findings provide a basis for bioenergetic modelling of rainbow trout populations in lakes of the central North Island of New Zealand.
Summary To investigate the carrying capacity and factors affecting growth of rainbow trout in Lake Rotoiti, we employed a bioenergetics model to assess the influence of stocking rates, timing of releases and prey abundance on growth and prey consumption. We hypothesised that stocking rates and prey abundance would affect growth and prey consumption by influencing per‐capita prey availability, and that the environmental conditions encountered by fish at the time of stocking would affect growth and consumption. Prey consumption of stocked rainbow trout was calculated with the Wisconsin bioenergetics model. We calculated growth trajectories of released trout based on data from stocked trout that were released in spring and autumn from 1993 to 2009 and then re‐captured by anglers. Diet, prey energy density, body mass lost during spawning and lake temperature were measured locally. Stocking timing had no effect on return rates to anglers or length or weight of caught fish. Although trout released in autumn were smaller than those released in spring, autumn‐released trout grew at a faster rate and had similar lengths and weights to spring cohorts after 2 years of growth in the lake. Modelled consumption parameters were negatively correlated with trout population size, suggesting that stocking rates (347–809 fish ha−1 year−1) caused density‐dependent effects on growth. Although common smelt (Retropinna retropinna) accounted for 85% of total prey consumption, no significant relationship was found between prey consumption by individual trout and adult smelt abundance, possibly because trout are targeting smaller smelt that our abundance estimate did not account for. Releasing trout in autumn appears to be advantageous for growth, possibly because (i) temperature is more suitable for growth in autumn–winter than in spring–summer and (ii) prey for small trout is abundant in autumn. Mild winter conditions appear to enhance overwinter survival and growth of rainbow trout in warm‐temperate lakes compared to higher latitudes. This implies that moderately productive warm‐temperate lake ecosystems are highly suitable for trout growth in winter, but less so in summer, when lake stratification and high nutrient levels may create conditions suitable for algal blooms and hypolimnetic deoxygenation. High growth rates of trout in warm‐temperate lakes can therefore be supported by timing releases to coincide with favourable winter conditions.
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