We provide a mitochondrial DNA-based phylogenetic hypothesis for 21
Tityus species collected in Venezuela, Trinidad, Brazil and Panama, including 12 taxa known to be toxic to humans. Our phylogenetic ...reconstruction is based on 850 nucleotides of the combined cytochrome oxidase subunit I and 16S rRNA genes for most species, and centered on Venezuelan scorpions owing to the detailed taxonomic and biogeographic information available for
Tityus in this region. The principal phylogenetic result was the strong support for mtDNA clades representing geographical groupings associated with the Perijá mountain range, the Mérida Andes, or the central and eastern coastal ranges in Venezuela, suggesting that vicariance has been a potent force in the diversification of local scorpions. Venezuelan
Tityus species have been organized by González-Sponga into three artificial morphological groups, “androcottoides”, “discrepans”, and “nematochirus”, based on the array of ventral carinae in metasomal segments II–IV. We also incorporated a fourth morphological group (“
Tityus clathratus”), recently documented in Venezuela. Our results do not support the clustering of the species in the “androcottoides” and “discrepans” morphological groups, which include the majority of taxa of medical importance, but provided support for the “nematochirus” species group.
T. clathratus was found to cluster with the Brazilian
T. serrulatus and
T. bahiensis. Divergence times of most clades are consistent with major events in the geological history of northern Venezuela and suggest that many Venezuelan
Tityus species formed in the late Miocene and the Pliocene. In turn, we used the
Tityus mtDNA phylogeny to determine the potential utility of phylogenetic systematics to predict
Tityus venom antigenic reactivity by testing the recognition of
T. nororientalis,
T. discrepans,
T. zulianus,
T. perijanensis, and
T. clathratus venoms by anti-
T. discrepans horse antibodies. Cross-reactivity was significantly higher for the closely related eastern (
T. nororientalis) and central coastal (
T. discrepans) species in comparison to the distantly related Andean (
T. zulianus) and Perijá (
T. perijanensis) species. Reactivity of
T. clathratus low mol. mass toxic components towards anti
-T. serrulatus and anti-
T. discrepans antivenoms was low, suggesting that venom components produced by the subgenus
Archaeotityus (which encompass “clathratus” species) diverge antigenically from other
Tityus scorpions.
We assessed the reproductive ecology of the American crocodile (Crocodylus acutus) on Coiba Island, Panama from JanuaryâDecember 2013. We examined nest site characteristics from JanuaryâApril and ...hatchling survivorship from AprilâDecember. Ten nests were examined at three nesting localities where 30% of the nests were found under forest canopies and 70% were exposed to sunlight (distance to nearest tree = 280 ± 110 cm). Half of the nests were built closer to the sea and the other half closer to bodies of freshwater (700 ± 360 cm). The nest dimensions were 17.5 ± 7.8 cm from the top of the clutch to the surface, 42.9 ± 9.9 cm from the bottom of the clutch to the surface, and 35.9 ± 3.6 cm wide at the top of the nest cavity. The average soil conditions in the nests consistently had high concentrations of potassium (69.3 mL/L) and manganese (9.2 mg/L), moderate concentrations of phosphorus (6.6 mg/L) and iron (3.7 mg/L), and low concentrations of zinc (0.5 mg/L) and copper (0.0 mL/L). Cation exchange capacity showed consistently high concentrations of calcium (2.2 cmol/kg), moderate of magnesium (1.1 cmol/kg), and low in aluminum (0.1 cmol/L). Volumetric water content was about 25.0 ± 2.6% at the bottom and 22.8 ± .3% in the middle of the clutches. Hatching success was 88.9%, of which 68.3% hatched by themselves or with the mother's aid and 20.6% hatched with our aid. Mean size of the mother was 219 ± 6.2 cm total length (TL) and 115.9 ± 3.0 cm snout-vent length (SVL). The incubation period was estimated to be 85â88 days. TL and SVL growth rate of those individuals were 0.03â0.16 cm/day and 0.00â0.09 cm/day, respectively. Population size was estimated to be 218.6 hatchlings in 22.4 km²; the hatchling population declined 65.7% after the first 2 months (May and June) and 95.9% by July, leaving only 0.5% remaining by December. This is the first study to assess nest-site characteristics and estimate hatchling survival in a Pacific population of American crocodiles.
To assess the historical biogeography of freshwater topminnows in the genus Poeciliopsis, we examined sequence variation in two mitochondrial genes, cytochrome b (1140 bp) and NADH subunit 2 (1047 ...bp). This widespread fish genus is distributed from Arizona to western Colombia, and nearly half of its 21 named species have distributions that border on the geologically active Trans-Mexican Volcanic Belt (TMVB), a region that defines the uplifted plateau (Mesa Central) of Mexico. We used the parametric bootstrap method to test the hypothesis that a single vicariant event associated with the TMVB was responsible for divergence of taxa found to the north and south of this boundary. Because the single-event hypothesis was rejected as highly unlikely, we hypothesize that at least two geological events were responsible for divergence of these species. The first (8–16 million years ago) separated ancestral populations that were distributed across the present TMVB region. A second event (2.8–6.4 million years ago) was associated with northward dispersal and subsequent vicariance of two independent southern lineages across the TMVB. The geological history of this tectonically and volcanically active region is discussed and systematic implications for the genus are outlined. Corresponding Editor: L. Bernatchez
Origins and biogeography of the chub, genus
Squalius (formerly within the genus
Leuciscus), in the Iberian Peninsula were inferred from comparison between patterns of geographic distribution and ...phylogenetic relationships among populations belonging to 14 European
Squalius species. The phylogeny recovered was based on the complete sequence of the mitochondrial cytochrome
b gene.
Squalius species were grouped into three major clades. The basal clade included species distributed across the ancient Paratethys Sea. The second clade included species from Central and East Europe and the northern areas of the Mediterranean basin towards Minor Asia. The third clade included species from the Mediterranean Peninsulas (Iberian, Italy, and Balkans). The Iberian
Squalius species do not constitutes a monophyletic group. Our data indicate that the Iberian Peninsula was colonized at least twice by two different monophyletic lineages, a meridional group and a Central Europe group. The amount of species diversity found in the Iberian Peninsula and the phylogenetic relationships among these species, together with their geographic distribution, suggest that the Central Europe lineage colonized the Iberian Peninsula at a latter time. Our data indicate that the northeastern Iberian lineage is phylogenetically close to Greek populations of
Squalius cephalus, while the second lineage formed a monophyletic group including
Squalius pyrenaicus,
Squalius carolitertii,
Squalius aradensis, and
Squalius torgalensis. The speciation process that generated these species and the geographic structure of their populations, principally in
S. pyrenaicus, can be attributed to paleogeographical events like the ancient endorrheism and the development of hydrographic basins.
Anopheles albimanus appears to be a single, albeit polymorphic, species that is not at mutation-drift equilibrium due to past geographic fragmentation and regional fluctuation in its effective ...population size. The
COI gene suggests a common pattern of historical isolation, subsequent haplotype mixing, and population expansion of four mtDNA
COI lineages in the late Pleistocene. Data from the
white gene do not reflect the high genetic diversity of the
COI, but are consistent with the scenario of late Pleistocene population expansion. Finally, lower genetic diversity by both the
COI and
white genes across Panama suggest that
An. albimanus populations contracted, then subsequently expanded toward Nicaragua and Ecuador.
Display omitted
► The map shows the geographic distribution of four
COI haplogroups (A, red), (B, green), (C, black) and (D, yellow) of
Anopheles albimanus. ► Three population demes defined by SAMOVA are outlined: Nicaragua, Costa Rica and the Atlantic coast of western Panama; the Pacific coast of western Panama, central-eastern Panama and the Caribbean coast of Colombia; and the Pacific coast of Colombia and Ecuador. ► The SP network of eighteen
white gene alleles (I–XVIII) and their geographical distributions.
We investigated the historical demography of
Anopheles albimanus using mosquitoes from five countries and three different DNA regions, the mitochondrial cytochrome oxidase subunit I gene (
COI), the single copy nuclear
white gene and the ribosomal internal transcribed spacer two (ITS2). All the molecular markers supported the taxonomic status of a single species of
An. albimanus. Furthermore, agreement between the
COI and the
white genes suggested a scenario of Pleistocene geographic fragmentation (i.e., population contraction) and subsequent range expansion across southern Central America.
Free-ranging ticks are widely known to be restricted to the ground level of vegetation. Here, we document the capture of the tick species
Amblyomma tapirellum
in light traps placed in the forest ...canopy of Barro Colorado Island, central Panama. A total of forty eight adults and three nymphs were removed from carbon dioxide–octenol baited CDC light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. To our knowledge, this represents the first report of questing ticks from the canopy of tropical forests. Our finding suggests a novel ecological relationship between
A. tapirellum
and arboreal mammals, perhaps monkeys that come to the ground to drink or to feed on fallen fruits.
There is little information on the reproductive biology of the male Baird's tapir (Tapirus bairdii). In this study, we characterized the ejaculate traits and evaluated the efficacy of 2 cryodiluents ...on sperm cryosurvival. Ejaculates were assessed for volume, pH, sperm motility, forward progression, osmolality, sperm concentration, sperm morphology, and acrosomal integrity. For cryopreservation, ejaculates with >50% total sperm motility were washed, and sperm pellets were resuspended in either Botu‐Crio (CryoVital, Grandau, Germany) or INRA 96 containing 2% egg yolk and 2.5% each of methyl‐ and dimethylformamide (INRA 96), and they were cryopreserved over liquid nitrogen vapor. Thawed samples were incubated in vitro (25°C) and evaluated for percent total sperm motility, forward progression, and acrosomal integrity at hourly intervals for 4 hours. Spermic ejaculates were obtained from all males, and the mean seminal volume, sperm concentration per milliliter, percent sperm motility, progressive status, and percent morphologically normal cells were 20.4 ± 4.3 mL, 101.2 ± 24.0 × 106/mL, 46.1% ± 5.0%, 2.9 ± 0.1, and 6.9% ± 1.4%, respectively. There was a positive significant correlation between percent normal sperm and animal age (r = 0.66; P < .004). Cryopreservation in either Botu‐Crio or INRA 96 resulted in a decline (P < .05) in percent sperm motility and acrosomal integrity. Sperm forward progression remained unaffected immediately after thawing in INRA 96 but continued to decline over time. These results characterize, for the first time, the ejaculate traits of the tapir; demonstrate that tapir spermatozoa can be cryopreserved in diluents containing amides alone or in combination with glycerol; and provide fundamental information critical for development of assisted reproductive technologies for the Baird's tapir.
Iberian minnows collectively known as the Tropidophoxinellus alburnoides Steindachner complex comprise diploid and polyploid forms with highly female biased sex ratios. Previous investigators ...suggested that all-female clonal reproduction and interspecific hybridization may occur in this complex. We examined nuclear (allozymes) and cytoplasmic genes (mtDNA) to assess the evolutionary origins, relationships, and reproductive modes of T. alburnoides from western Spain. The multi-locus allozyme data clearly revealed the hybrid nature of all polyploid forms of this fish and some diploid forms as well. Diagnostic markers identified fish from the genus Leuciscus as the paternal ancestor of hybrids in the Duero and Guadiana River Basins. Additionally, analysis of nuclear markers revealed that hybridogenetic reproduction occurs in the diploid and triploid hybrids. The hybrids fully express the paternal Leuciscus genome and then discard it during oogenesis. Hybridogenetic ova contain only maternal nuclear genes and mtDNA from a non-hybrid T. alburnoides ancestor. Apparently diploid and triploid hybrids of T. alburnoides persist as sperm parasites on males of a sexually reproducing Leuciscus host species.
PDF
