A newly discovered skull of the temnospondyl amphibian Dendrerpeton acadianum Owen

1987 ◽  
Vol 24 (4) ◽  
pp. 796-805 ◽  
Author(s):  
Stephen J. Godfrey ◽  
Anthony R. Fiorillo ◽  
Robert L. Carroll

A virtually complete three-dimensional skull of a subadult of the temnospondyl amphibian Dendrerpeton acadianum provides new information on the structure of the palate and lower jaw. The left stapes appears to lie in a natural position on the quadrate ramus of the pterygoid. The proportionately large otic ossicle probably precluded it from having acted as a transmitter of airborne vibrations from a tympanum to the inner ear. The use of the term "otic notch" should be restricted to amphibians or reptiles in which the embayment of the posterior margin of the cheek is accompanied by the presence of a slender rod-like stapes that could have functioned as part of an impedance matching system. In those species in which a notch is present but the stapes is a massive "supporting" element, the term "squamosal embayment" should be used, rather than "otic notch." The squamosal embayment in early tetrapods may have been inherited directly from their fish ancestors and had no functional relationship to hearing.

2017 ◽  
Vol 4 (8) ◽  
pp. 170685 ◽  
Author(s):  
Alessandro Palci ◽  
Mark N. Hutchinson ◽  
Michael W. Caldwell ◽  
Michael S. Y. Lee

The inner ear morphology of 80 snake and lizard species, representative of a range of ecologies, is here analysed and compared to that of the fossil stem snake Dinilysia patagonica , using three-dimensional geometric morphometrics. Inner ear morphology is linked to phylogeny (we find here a strong phylogenetic signal in the data that can complicate ecological correlations), but also correlated with ecology, with Dinilysia resembling certain semi-fossorial forms ( Xenopeltis and Cylindrophis ), consistent with previous reports. We here also find striking resemblances between Dinilysia and some semi-aquatic snakes, such as Myron (Caenophidia, Homalopsidae). Therefore, the inner ear morphology of Dinilysia is consistent with semi-aquatic as well as semi-fossorial habits: the most similar forms are either semi-fossorial burrowers with a strong affinity to water ( Xenopeltis and Cylindrophis ) or amphibious, intertidal forms which shelter in burrows ( Myron). Notably, Dinilysia does not cluster as closely with snakes with exclusively terrestrial or obligate burrowing habits (e.g. scolecophidians and uropeltids). Moreover, despite the above similarities, Dinilysia also occupies a totally unique morphospace, raising issues with linking it with any particular ecological category.


Author(s):  
John R. BOLT ◽  
R. Eric LOMBARD

ABSTRACTThe reconstructed palate ofWhatcheeria deltaeindicates a skull that was unusually narrow: at least 2.2 times longer than wide if the pterygoids are conservatively placed in the horizontal plane. This maximum width is narrower than any other early tetrapod reconstructed so far. Rotating the pterygoids to produce a vaulted palate would produce an even narrower skull. Primitive palatal features include very narrow interpterygoid vacuities and a vomer, palatine, and ectopterygoid with fang-sized replacement pairs. It is derived in that there is no anterior palatal fenestra and the premaxilla has a substantial palatal shelf – a combination of characters shared only with Proterogyrinus among early tetrapods. There is a possible septomaxilla in one specimen.Whatcheeriadiffers from and is more derived thanPederpes, its likely sister taxon, in that only the pterygoid is covered with denticles, the vomer, palatine, and ectopterygoid containing labyrinthine teeth only. Reconstructed dental occlusion indicates that the large choana apparently accommodated the large dentary fangs; this would be a unique feature among early tetrapods. The palatal ramus of the pterygoid is longer than the quadrate ramus, which does not have a descending flange. Like Meckel's cartilage in the lower jaw, the palatoquadrate is fully ossified in larger specimens, such that in a posterior view of the skull the pterygoid is mostly hidden from sight by the epipterygoid. The ossified neurocranium consists of the basiparasphenoid and basioccipital; no ossified sphenethmoid has been found. Remains of otic capsules are partial, crushed, and smeared, so no useful morphology is available. The stapes appears to be more columnar and less plate-like than in many other primitive, early tetrapods.


1993 ◽  
Vol 265 (6) ◽  
pp. L521-L548 ◽  
Author(s):  
R. P. Bolender ◽  
D. M. Hyde ◽  
R. T. Dehoff

Today all structural information of the lung can be quantified and interpreted in the three-dimensional space of real-world biology. Remarkable achievements in the theory and practice of biological stereology are creating a new generation of data suitable for constructing structural hierarchies. Such hierarchies serve to organize and link biological data, thereby providing a framework on which to build new information systems. In this review, we describe the new tools of quantitative morphology and show how they can be used to design new experiments for lung research.


2010 ◽  
Vol 8 (3) ◽  
pp. 120-128 ◽  
Author(s):  
Glen H. MacDonald ◽  
Edwin W Rubel

2007 ◽  
Vol 4 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Qing Liu ◽  
Patrick Fay ◽  
Gary H. Bernstein

Quilt Packaging (QP), a novel chip-to-chip communication paradigm for system-in-package integration, is presented. By forming protruding metal nodules along the edges of the chips and interconnecting integrated circuits (ICs) through them, QP offers an approach to ameliorate the I/O speed bottleneck. A fabrication process that includes deep reactive ion etching, electroplating, and chemical-mechanical polishing is demonstrated. As a low-temperature process, it can be easily integrated into a standard IC fabrication process. Three-dimensional electromagnetic simulations of coplanar waveguide QP structures have been performed, and geometries intended to improve impedance matching at the interface between the on-chip interconnects and the chip-to-chip nodule structures were evaluated. Test chips with 100 μm wide nodules were fabricated on silicon substrates, and s-parameters of chip-to-chip interconnects were measured. The insertion loss of the chip-to-chip interconnects was as low as 0.2 dB at 40 GHz. Simulations of 20 μm wide QP structures suggest that the bandwidth of the inter-chip nodules is expected to be above 200 GHz.


ORL ◽  
2009 ◽  
Vol 71 (6) ◽  
pp. 334-341 ◽  
Author(s):  
Fang-Lu Chi ◽  
Zhao Han ◽  
Pei-Dong Dai ◽  
Yi-Bo Huang ◽  
Ning Cong ◽  
...  

2013 ◽  
Vol 813 ◽  
pp. 225-229
Author(s):  
Bin Zhao ◽  
Jian Guo Li ◽  
Shao Wei Sun ◽  
Xin Peng Zhou ◽  
Zhen Bin Wang ◽  
...  

As the lack of work on comprehensive rock physical properties in deep geophysical exploration in Yudu-Ganxian ore concentration area, this paper focuses in comprehensive and systematic study about the comprehensive rock physical properties in this area. Known from the rock (ore) actual distribution in this area, this paper presents the comprehensive rock physical properties research method of the area, which use varieties of techniques to collect specimens systematic, determine the physical parameters, and even study the distribution characteristics and variation law of rock (ore) integrated rock physical properties parameters. In this paper, the results can provide the new information about integrated rock physical property parameters for understanding and explaining the integrated geophysical anomaly, providing the basis for the future in Nanling to carry out deep geophysical three-dimensional exploration and deep metallogenic prognosis.


Sign in / Sign up

Export Citation Format

Share Document