Texas beckons.

Many Canadian medical families have been approached by US headhunters anxious to recruit family physicians to practise in the US. Lynne Sears Williams and her husband, Calgary family physician Jim Williams, went to Texas to see what opportunities awaited. In this article she describes the high and low points of recruitment efforts south of the border.     

Preferential predatory peeling: Ammonoid vs. nautiloid shells from the Upper Carboniferous of Texas,USA

Narrow groove-like excavations on ammonoid and coiled nautiloid shells are rare in Upper Carboniferous units from Texas, USA. The morphological characteristics of the excavation grooves typically are confined to the ventral and ventrolateral parts of the outer whorl of the shell, are narrower than the length, and have irregular edges where small segments or chips of shells have been removed. Analysis of these features reveals a statistically significant preferential occurrence on ammonoids (1.195% of ca. 3515 specimens) as compared to coiled nautiloids (0.506% of ca. 2965 specimens). The ammonoids typically have longer excavations that penetrate the phragmocone more frequently than those observed in the coiled nautiloids. The groove-like excavations were probably formed by the removal and peeling of shell material by one or more predatory or scavenging arthropods to obtain organic material (tissue and membranes) within the ammonoid and nautiloid body chambers and phragmocones. The excavations probably occurred when the cephalopod was alive (i.e., the cause of death) or shortly after the cephalopod's death. There is no evidence that the excavations are related to sheltering by the excavating organism.     

Unusual aetosaur armor from the Upper Triassic of West Texas,U.S.A.

We report two unusual aetosaur scutes from the Tecovas Member of the Dockum Formation, Chinle Group (upper Carnian) of Crosby County, Texas, U.S.A. Originally collected by University of Michigan expeditions in the 1920’s, these scutes cannot be assigned with certainty to any known species of aetosaurs known from the American Southwest. One of these scutes may be a cervical horn ofParatypothorax, and if so confirms the similarities of this aetosaur toDesmatosuchus in the possession of horned lateral spikes. The other is a paramedian scute of a new aetosaur taxon inadequately known at present to be assigned a formal name. These scutes indicate that aetosaurs were more diverse in the Chinle Group than currently known, but do not alter the robust Late Triassic biochronology based on aetosaurs.     

Palynology of the Dockum group (Upper Triassic), Texas,U.S.A.

A palynofloral assemblage is described from the Upper Triassic Dockum Group of Texas. Forty palynomorph species are recorded and these are correlated with European Upper Triassic assemblages. The Dockum Group assemblage is considered to be of late Karnian age.Two new genera, Tulesporites gen. nov., type species T. briscoensis sp. nov., and Daughertyspora gen. nov., type species D. chinleanus (Daugherty) comb. nov. have been erected; new species are Converrucosisporites matsenii sp. nov., Pyramidosporites traversei sp. nov., Callialasporites triassicus sp. nov., Plicatipollenites minutotriletus sp. nov., Triadispora dockumensis sp. nov., Bhardwajispora jansonii sp. nov., Protodiploxypinus americus sp. nov., P. ujhelyi sp. nov., Klausipollenites gouldii sp. nov., Pityosporites old-hamensis sp. nov., Abietineaepollenites bujakii sp. nov., Falcisporites oviformis sp. nov. and F. tecovasensis sp. nov.     

Larval Hannemania sp. infestations of Spea spp. in the Southern High Plains, Texas, USA

We describe a case history of larval Hannemania sp. (Acari: Trombiculidae) infestations in two spadefoot toads (Spea spp. Anura: Pelobatidae) captured from playa wetlands in the Southern High Plains, Texas. Hannemania sp. larvae were superficially attached to the skin, not encysted, and dermal changes were not observed. Gross field examinations revealed a presumed occurrence of Hannemania sp. in Spea spp. at four of 24 wetlands in 2003 and 2004. Although other species of amphibians were present (Ambystoma tigrinum mavortium, Bufo cognatus, Bufo debilis insidior, Pseudacris clarkii, Gastrophryne olivacea, Rana blairi, Scaphiopus couchii), investigators did not observe infestations in these species. Future research should focus on identifying this Hannemania to species level and determining if it influences Spea spp. survival.     

Morphological variation in intergrade pupfish populations from the Pecos River, Texas, U.S.A.

In the early 1980s, sheepshead minnow Cyprinodon variegates was introduced into the Pecos River, Texas, U.S.A. where it hybridized with the endemic Pecos pupfish C. pecosensis . By 1985, pupfish populations throughout approximately 300 km of the river consisted exclusively of individuals of hybrid origin (intergrades). There was significant ( P <0·05) geographic variation in most morphological characters; the general pattern of variation was of a bidirectional cline centred near Pecos, Texas. At that site, morphology of intergrade populations resembled mostly that of the introduced species. Upstream and downstream from Pecos, morphology shifted progressively toward that typical of the native form. Intergrade populations were morphologically intermediate to the parental forms, showed a rapid approach to random assortment of characters, and generally exhibited greater morphological variability than occurred in either parent species. These observations and the consistent lack of bimodality in frequency distributions of a morphological hybrid index support the contention that intergrade populations comprise panmictic admixtures of C. variegates and C. pecosensis .     

Identification, capture, and biotelemetry of socially living monkeys.

Remote monitoring of physiologic function using socially living monkeys differs from that using individually housed animals in that access to subjects may be limited. Some logistic aspects of working with socially housed monkeys are reviewed, including identification of individuals and capturing subjects. Methods of remote sampling include hormonal assays of urine and fecal samples, measurement of physical indices as estimates of reproductive status, and the use of telemetry devices to record activity and biopotentials. Key factors in the selection of a telemetry system are discussed. In many cases, remote monitoring may permit assessment of physiologic function without the stress of handling or restraint.