We describe several novel morphological features in the nasal region of the hammerhead shark Sphyrna tudes. Unlike the open, rounded incurrent nostril of non-hammerhead shark species, the incurrent nostril of S. tudes is a thin keyhole-like aperture. We discovered a groove running anterior and parallel to the incurrent nostril. This groove, dubbed the minor nasal groove to distinguish it from t...

Long-term fisheries independent gill net surveys conducted in Texas estuaries from 1975 to 2006 were used to develop spatially explicit estuarine habitat use models for 3 coastal shark species: bull shark Carcharhinus leucas, blacktip shark C. limbatus, and bonnethead shark Sphyrna tiburo. Relationships between environmental predictors and shark distribution were investigated using boosted regr...

As demonstrated in past studies, androgens appear to play critical roles in regulating reproduction in male sharks. However, little is known about the cell-specific actions of androgens in these fishes. To address this, this study examined androgen targets in reproductive organs of a seasonally reproducing shark, the bonnethead (Sphyrna tiburo). A partial bonnethead AR cDNA clone was isolated a...

Elasmobranchs are one of the most diverse groups in the marine realm represented by 18 orders, 55 families and about 1200 species reported, but also one of the most vulnerable to exploitation and to climate change. Phylogenetic relationships among main orders have been controversial since the emergence of the Hypnosqualean hypothesis by Shirai (1992) that considered batoids as a sister group of...

In the present study the brain mass to body mass ratio and external morphological features of the brain of Mobula japanica, Mobula thurstoni and Manta birostris (devilrays) are described. The Mobulids extended the upper boundary of the minimum convex polygon described earlier by other authors for batoids, which is plotted on a double logarithmic scale of brain to body mass, causing some change ...

We propose a novel agent-based implementation of Festingers’ Social Comparison Theory (SCT). The Social Comparison Model (SCM) consists of connectionist networks that simulate agent-level social comparison processes. Agent networks are combined into a adaptive network structure that is shaped by social comparisons between individual agents. Simulations show how the SCM produces behavior consist...

a r t i c l e i n f o The subject of positive attitudes toward self and others has recently been the recipient of growing attention. In two studies, we explored self-compassion (SC) and forms of concern for others as they relate to various aspects of psychological functioning. SC was negatively associated with pathological concern (PC) and not associated with healthy concern (HC). PC was indica...

Middle Miocene (Badenian) chondrichthyan fossils collected from the Tekeres Schlieren Member of Baden Formation at (southern Hungary, Mecsek Mts) are described here. The assemblage is exceptionally diverse and well-preserved, consists holocephalans, selachians batomorphs. Nine taxa reported for first time Badenian Central Paratethys: Ischyodus sp., Hexanchus cf. nakamurai, Centrophorus Isistius...