Increasing species richness along elevational gradients is associated with niche packing in bat assemblages.

The change in species richness along elevational gradients is a well-known pattern in nature. Niche theory predicts that increasing species richness in assemblages can either lead to denser packing of niche space ('niche packing') or an expansion into its novel regions ('niche expansion'). Traditionally, these scenarios have been studied using functional traits but stable isotopes provide advantages such as identifying the degree of resource specialisation, or niche partitioning among functionally similar species. In this study, we evaluate the relevance of niche packing versus niche expansion by investigating stable carbon and nitrogen isotopic niche width and overlap among 23 bat species from six functional groups across a 1500 m elevational gradient in the Himalaya. Our results suggest that an increase in species richness in the low elevation is accompanied by small niche width with high overlap, whereas the high elevation assemblage shows large niche width with low overlap among functional group members. At the functional group level, edge-space foraging, trawling, and active gleaning bats have the highest niche width while passive gleaning bats that are only found in high elevations are isotopic specialists showing low overlap with other groups. Edge and open-space foraging bats showed idiosyncratic changes in niche width across elevations. We also find that the niches of rhinolophid bats overlap with edge-space and open-space foraging bats despite their unique functional traits. These results support the idea that at low elevations high species richness is associated with niche packing while at high elevations strong niche partitioning prevails in dynamic and resource-poor environments. We conclude that although high elevation animal assemblages are often 'functionally underdispersed', that is show homogenous functional traits, our approach based on stable isotopes demonstrates niche partitioning among such functionally similar species.

Radiological Diagnosis of a Rare Prepontine Lesion: Ecchordosis Physaliphora.

Ecchordosis physaliphora (EP) is a notochordal remnant tissue rarely encountered during routine clinical practice. These lesions usually do not produce any significant symptoms as they are slow-growing and mostly small in size. Symptoms are due to mass effects on adjacent structures when they are large or extra-tumoral hemorrhage. Because of histological similarity with chordoma, diagnosis is challenging, and this differentiation is essential as the disease course and treatment differ significantly. Imaging plays a crucial role in identifying and distinguishing these lesions. We report the case of a 16-year-old male who presented with intermittent headache and neck pain for six months. His routine clinical examinations were within normal limits. On neurological assessment, there was no focal neurodeficit. Evaluation of cranial nerves did not reveal any evidence of palsy. Routine hematological tests were also normal. A computed tomography (CT) scan of the brain revealed a mass in front of the pons. Magnetic resonance imaging (MRI) for further evaluation revealed a T1 hypointense and T2/fluid-attenuated inversion recovery hyperintense lesion in the pre-pontine cistern. There was no enhancement in the mass either in the post-contrast CT or MRI scans. There was no bony erosion and clivus was normal. Based on the location and characteristic imaging features, a diagnosis of EP was made. There may be several other lesions that may present as a mass in the pre-pontine region. Histopathological tests may find it difficult to distinguish between lesions that originate from notochord remnants. Imaging studies play a vital role in confirming the diagnosis and help in planning treatment and follow-up.

Functional diversity of Himalayan bat communities declines at high elevation without the loss of phylogenetic diversity.

Species richness exhibits well-known patterns across elevational gradients in various taxa, but represents only one aspect of quantifying biodiversity patterns. Functional and phylogenetic diversity have received much less attention, particularly for vertebrate taxa. There is still a limited understanding of how functional, phylogenetic and taxonomic diversity change in concert across large gradients of elevation. Here, we focused on the Himalaya-representing the largest elevational gradients in the world-to investigate the patterns of taxonomic, functional and phylogenetic diversity in a bat assemblage. Combining field data on species occurrence, relative abundance, and functional traits with measures of phylogenetic diversity, we found that bat species richness and functional diversity declined at high elevation but phylogenetic diversity remained unchanged. At the lowest elevation, we observed low functional dispersion despite high species and functional richness, suggesting a niche packing mechanism. The decline in functional richness, dispersion, and divergence at the highest elevation is consistent with patterns observed due to environmental filtering. These patterns are driven by the absence of rhinolophid bats, four congeners with extreme trait values. Our data, some of the first on mammals from the Himalayan region, suggest that in bat assemblages with relatively high species diversity, phylogenetic diversity may not be a substitute to measure functional diversity.

Radiological diagnosis of rare pancreatic serous cystadenoma.

Serous cystadenoma of the pancreas, also known as microcystic adenoma, is a very rare type of pancreatic neoplasm. It is a benign cystic lesion. It is composed of many small cysts lined by cuboidal or flattened cells containing glycogen. Herein, we report a rare case of serous cystadenoma of the pancreas in an 82-year-old male. The tumor was located in the body and tail of the pancreas and postoperative sample revealed a sponge-like appearance due to multiple tiny cysts containing clear serous fluid. Microscopic analysis showed cystic spaces lined by cuboidal cells with intracytoplasmic glycogen.

Diagnosis of tubo-ovarian filariasis with retroperitoneal extension: A radiological challenge.

The purpose of this report is to describe a very rare case of bilateral tubo-ovarian filariasis with retroperitoneal extension in a 20-year-old female patient. The patient complained of low-grade fever with whitish cloudy urine. Computerized tomography imaging revealed hypodense cystic abdominopelvic masses with nonenhancing septations involving the retroperitoneum and ultrasound showing the characteristic "dancing larvae sign" suggesting filariasis.