Disparity Changes in 370 Ma Devonian Fossils: The Signature of Ecological Dynamics?

Early periods in Earth's history have seen a progressive increase in complexity of the ecosystems, but also dramatic crises decimating the biosphere. Such patterns are usually considered as large-scale changes among supra-specific groups, including morphological novelties, radiation, and extinctions. Nevertheless, in the same time, each species evolved by the way of micro-evolutionary processes, extended over millions of years into the evolution of lineages. How these two evolutionary scales interacted is a challenging issue because this requires bridging a gap between scales of observation and processes. The present study aims at transferring a typical macro-evolutionary approach, namely disparity analysis, to the study of fine-scale evolutionary variations in order to decipher what processes actually drove the dynamics of diversity at a micro-evolutionary level. The Late Frasnian to Late Famennian period was selected because it is punctuated by two major macro-evolutionary crises, as well as a progressive diversification of marine ecosystem. Disparity was estimated through this period on conodonts, tooth-like fossil remains of small eel-like predators that were part of the nektonic fauna. The study was focused on the emblematic genus of the period, Palmatolepis. Strikingly, both crises affected an already impoverished Palmatolepis disparity, increasing risks of random extinction. The major disparity signal rather emerged as a cycle of increase and decrease in disparity during the inter-crises period. The diversification shortly followed the first crisis and might correspond to an opportunistic occupation of empty ecological niche. The subsequent oriented shrinking in the morphospace occupation suggests that the ecological space available to Palmatolepis decreased through time, due to a combination of factors: deteriorating climate, expansion of competitors and predators. Disparity changes of Palmatolepis thus reflect changes in the structure of the ecological space itself, which was prone to evolve during this ancient period where modern ecosystems were progressively shaped

Adenoid cystic carcinoma of the distal trachea: a case report

Primary malignant tumors of the trachea are very rare with incidence less than two cases in a million per year and only ten percent of these are adenoid cystic carcinomas. Eighty percent of all tracheal tumors are malignant. Diagnosis is usually late because symptoms mimic other conditions like asthma. The clinical presentation may be dramatic when the airway is almost obstructed and emergency recanalization is necessary. Diagnosis is made by chest computed tomography scan or magnetic resonance imaging. Definitive treatment is surgical resection alone or followed by radiation therapy or radiation therapy alone. Radical resection is accomplished only in about half of all cases because of the submucosal growth of the tumor and limited length of tracheal resection. The role of adjuvant radiation therapy in negative resection margin cases is not clear but all patients with positive resection margin benefit from radiation therapy. We present a rare case of a 43-year-old male patient with primary adenoid cystic carcinoma of the distal trachea treated by emergency bronchoscopic recanalization and resection of the tracheal tumor with end-to-end anastomosis

Bronchopulmonary sequestration in adults - a Croatian single institution experience

Pulmonary sequestration (PS) is a congenital lung defect rarely diagnosed in adults. PS is often misdiagnosed or not recognized early, delaying surgical management. The aim of this case series analysis was to determine the characteristics of all PS patients with surgical resections occurring over an 8-year period in a single tertiary centre