The topography and geology of the Cross Timbers and surrounding regions in northern Texas

Hill, Robert Thomas

doi:10.2475/ajs.s3-33.196.291

Cited by 35 publications

(5 citation statements)

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“…Thus, in its retreat it left arenaceous materials (Western Cross Timbers), calcareous materials (Fort Worth Prairie), arenaceous materials (Eastern Cross Timbers), and other marine deposits originally laid down upon the marginal bottoms of a sea which in its general retreat also at times advanced. Hill ( 1887) first stated that the position of the Cross Timbers was adapted to geologic formations, being upon outcrops of certain arenaceous formations of Cretaceous rocks and with deep permeable regolith and sandy soils which favored tree growth. These he contrasted with the close-textured calcareous soils of the treeless intervening prairie.…”

Section: Early Accounts Of Vegetationmentioning

confidence: 99%

The Vegetation of the Western Cross Timbers

Dyksterhuis¹

1948

Ecological Monographs

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Section: Early Accounts Of Vegetationmentioning

confidence: 99%

The Vegetation of the Western Cross Timbers

Dyksterhuis¹

1948

Ecological Monographs

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“…The linear regression was performed using the ‘lme4’ package in R (Bates et al., 2015). Additionally, we conducted χ 2 tests of independence between the presence and absence of insects at host plant sample sites located in central/east Texas vs. west Texas, using the Pecos River (longitude: −101.3507), the traditional demarcation of the Trans‐Pecos ecoregion, as our dividing line (Hill, 1887).…”

Section: Methodsmentioning

confidence: 99%

A test of adaptive divergence in a newly discovered host association of the soapberry bug Jadera haematoloma on Mexican buckeye, Ungnadia speciosa

Comerford

Carroll

Egan

2021

Entomologia Exp Applicata

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Host races represent an important step in the speciation process of phytophagous insects as they reflect the maintenance of genetically divergent host‐associated populations in the face of appreciable gene flow. The red‐shouldered soapberry bug, Jadera haematoloma (Herrich‐Schäffer) (Hemiptera: Rhopalidae), is an oligophagous seed predator with a history of host race evolution on plant associations in the (soapberry) family Sapindaceae. Soapberry bugs are a model group for understanding rapid ecological adaptation to their hosts, and hence good candidates for investigating evolutionary divergence in host associations over short timescales. Here, we describe the recent discovery of Mexican buckeye, Ungnadia speciosa Endl., as a host of J. haematoloma in a region of the Chihuahuan desert including west Texas and southeastern New Mexico, USA. This host differs from J. haematoloma’s previously recorded hosts in the Sapindaceae in seed chemistry, ecology, and phylogeny. The tendency toward rapid, host‐associated adaptations by populations of J. haematoloma and the unique biology of the newly discovered Ungnadia host create the opportunity for potential host race formation, as it overlaps geographically with two previously recorded host plants in this region – the native western soapberry tree, Sapindus saponaria var. drummondii (Hook & Arn.), and the non‐native goldenrain tree, Koelreuteria paniculata Laxm. We explore the possibility of host race formation on Ungnadia‐associated insects by testing for host‐associated differentiation in morphology and feeding behaviors. We find evidence of differentiation in the length of the mouth parts, which is an ecologically relevant feeding trait between host plant species with larger or smaller seed capsules. This divergence is maintained in the face of potential gene flow by reproductive isolation in the form of habitat isolation, which we detect in host preference trials. Together, our results demonstrate that soapberry bugs associated with this newly discovered host exhibit morphological and behavioral traits consistent with host race formation, but additional work is required to confirm its state along the speciation continuum.

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“…The Cretaceous-age rocks (listed in ascending order) in the study area are part of the Trinity Group (Hill, 1888;Ross, 1943;Clark and others, 2009;Blome and Clark, 2014), Edwards Group (Hill and Vaughan, 1898;Rose, 1972;Maclay and Small, 1976), Devils River Limestone (Udden, 1907), Washita Group (Adkins, 1932), Eagle Ford Group (Hill, 1887;Wilmarth, 1938), Austin Group (Shumard, 1860;Adkins, 1932), Taylor Group (Hill, 1892;Stenzel, 1938), and igneous intrusive rocks (Liddle, 1918). Lithologic units are described throughout this report in ascending order.…”

Section: Geologic Frameworkmentioning

confidence: 99%