Aim: The processes that generate biodiversity occur at finer scales than are often studied, particularly in freshwater systems of the northern Neotropics. We investigate whether fine-scale biogeographic patterns are present within the larger Grijalva-Usumacinta Area of Endemism (AoE)-a region in Middle America where nearly 60% of freshwater fishes are endemic-and if present-day river basins are single historical units. Location: Northern Central America and southern Mexico.

Revista Mexicana de Biodiversidad 89 (Suplem. 2018): S118 -S130 Suplemento Peces nativos y pesca artesanal en la cuenca Usumacinta, GuatemalaNative fish fauna and artisanal fisheries in the Usumacinta basin, ResumenLa ictiofauna nativa de la cuenca del río Usumacinta se documentó en el noroeste de Guatemala para conocer la composición de los peces nativos en 20 sitios y su importancia en la pesca artesanal. El estudio incluyó recolecta de las especies con diversas artes de pesca, evaluación de abundancia de las especies mediante muestreos en transectos e identificación de las mismas en los mercados de venta, y en entrevistas con pescadores. Se identificó un total de 54 especies, 38 géneros, 18 familias y 8 órdenes. Las familias más abundantes fueron Characidae (3 especies), Poeciliidae (12 especies) y Cichlidae (22 especies), y en términos de riqueza el 68% de las especies corresponden a las familias Cichlidae y Poeciliidae. Al menos 38 especies nativas y 7 exóticas fueron identificadas en la pesca artesanal, de las cuales Centropomus undecimalis., Megalops atlanticus y Atractosteus tropicus son de alto valor comercial. Entre las 7 especies exóticas identificadas solo las especies del género Pterygoplichthys no son parte de la pesca artesanal. Los peces del área se dividen en 2 grandes grupos, uno en las zonas bajas de Petén y otro en las zonas altas de Las Verapaces y la pesca artesanal varía de acuerdo con este patrón. Según el estudio, a pesar de las especies exóticas, la pesca en la cuenca del Usumacinta está basada principalmente en especies nativas. Se requieren medidas de control del pez diablo exótico Pterygoplichthys spp. para evitar la propagación de sus poblaciones y mitigar los efectos negativos en la comunidad íctica nativa. AbstractThe native fish fauna was characterized in 20 sites along three drainage areas of the Usumacinta river basin in northwestern Guatemala to understand the native fish fauna contribution and its importance to artisanal fisheries.

Fetal malignancies that are capable of metastasizing to other fetal organs and the placenta are exceedingly rare. Fetal tumors are suspected on ultrasonography in the presence of structures of abnormal shape or size that are occasionally associated with polyhydramnios and hydrops. Most of the large abdominal masses detected antenatally are renal in origin, although adrenal tumors should also be kept in mind in their differential diagnosis. We report a case of a large-for-gestational-age fetus with abdominal distention secondary to bilateral adrenal carcinoma, polyhydramnios and placental enlargement. Postmortem histological findings included nesidioblastosis, (i.e. hyperplasia of the cells of the islets of Langerhans) and adrenocortical cytomegaly, suggestive of a form of Beckwith-Wiedemann syndrome.

Choosing among types of genomic markers to be used in a phylogenomic study can have a major influence on the cost, design, and results of a study. Yet few attempts have been made to compare categories of next-generation sequence markers limiting our ability to compare the suitability of these different genomic fragment types. Here we explore properties of different genomic markers to find if they vary in the accuracy of component phylogenetic trees and to clarify the causes of conflict obtained from different datasets or inference methods. As a test case, we explore the causes of discordance between phylogenetic hypotheses obtained using a novel dataset of ultraconserved elements (UCEs) and a recently published exon dataset of the cichlid tribe Heroini. Resolving relationships among heroine cichlids has historically been difficult, and the processes of colonization and diversification in Middle America and the Greater Antilles are not yet well understood. Despite differences in informativeness and levels of gene tree discordance between UCEs and exons, the resulting phylogenomic hypotheses generally agree on most relationships. The independent datasets disagreed in areas with low phylogenetic signal that were overwhelmed by incomplete lineage sorting (ILS) and non-phylogenetic signals. For UCEs, high levels of ILS were found to be the major cause of gene tree discordance, whereas, for exons, non-phylogenetic signal is most likely caused by a reduced number of highly informative loci. This paucity of informative loci in exons might be due to heterogeneous substitution rates that are problematic to model (i.e., computationally restrictive) resulting in systematic errors that UCEs (being less informative individually but more uniform) are less prone to. These results generally demonstrate the robustness of phylogenomic methods to accommodate genomic markers with different biological and phylogenetic properties. However, we identify common and unique pitfalls of different categories of genomic fragments when inferring enigmatic phylogenetic relationships.

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Prenatal diagnosis of dacryocystocele is straightforward. A considerable number of lesions are bilateral, and many resolve in utero spontaneously or neonatally after minimal intervention. For those not resolving by the time of the delivery, ophthalmologic or rhinologic consultation is warranted because of potential complications. Three-dimensional sonography may provide a noninvasive method for evaluating these cystic masses and may contribute to the avoidance of additional diagnostic techniques in the neonatal period.

Diadromous fishes can exhibit interesting evolutionary and population‐level patterns given their use of freshwater and marine environments as part of their life histories. The River goby genus Awaous are prominent members of riverine ichthyofaunas and occur throughout Atlantic and Pacific slopes of the Americas from the southern United States to Ecuador and Brazil. Here we study the widespread and polymorphic Awaous banana complex to assess phylogeographic patterns and test previous hypotheses that all populations of this species in the Americas belong to the same species. Analysis of sequence data based on the mitochondrial cytochrome oxidase I gene shows multiple clades within the Atlantic and Pacific basins, which correspond to previously described species. Additionally, haplotype analysis demonstrates unique and unconnected networks between these species. Within these clades we document biogeographic patterns that are congruent with results of other co‐occurring diadromous species, as well as a novel biogeographic pattern for the region. Our results support the recognition of distinct species of Awaous in the Atlantic (A. banana and A. tajasica) and Pacific (A. transandeanus) basins. These results are concordant with previously established morphological characters permitting the separation of these species.

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