scholarly journals Body size and shape in insular environments and applications of the island rule in biological anthropology

2021 ◽  
Author(s):  
◽  
Colleen Brennan Young
Keyword(s):  
Body Size ◽  
Biological Anthropology ◽  
Human Populations ◽  
Size And Shape ◽  
Island Fox ◽  
Research Areas ◽  
Reduced Body ◽  
Island Evolution ◽  
Body Sizes ◽  
History Of

The discovery of small-bodied hominin fossils in 2004 on the island of Flores, Indonesia, unearthed a large debate within biological anthropology. This debate has exemplified that there are questions and research areas that biological anthropologists do not understand about island evolution. To improve understanding on the causes and products of evolution within island areas for biological anthropologists, this dissertation addresses three overarching research areas relevant to the biological anthropology community. The first is an analysis of how primate body sizes vary on islands, with interpretations that are anchored in the evolutionary history of body sizes of primates. Primates that initially evolved body sizes to survive within a frugivorous niche, with elongated life spans to improve survival in unpredictable environments, have body sizes distributed among islands in relation to the presence of absence of these pressures. Smaller islands contain more large, bodied primates overall, whereas larger islands contain more small-bodied ones. Second, an analysis of island fox body size and shape indicates that island foxes have reduced body sizes and divergent skeletal traits compared to mainland, closely related counterparts. Distinct body proportions are likely due to selection because allometric scaling of limb lengths to body mass are divergent for the island fox. Further, the island fox is not a scaled down version of the mainland fox, with limbs decreasing in size at a faster rate compared to the mainland. Last, an investigation on the diversity of two human populations in the Baja California peninsula demonstrates that Amerindians who migrated to and survived in these regions were impacted by ecogeographic pressures in different degrees, likely related to access to resources. Heat-adapted skeletal traits are apparent in both human populations who inhabited this hot desert, but body size is distinct for the two groups. Body size is smaller for individuals with less access to marine resources and increased susceptibility to periods of drought and starvation. Body size is larger for humans with convenient access to oceanic and terrestrial resources. These studies demonstrate that primates, omnivores, and humans are not immune to the effects of insularity as has been suggested. Rather, interpreting body size and shape alterations requires contextualizing the organism with their evolutionary histories and subsequent interactions within the island areas. Body size alterations are the result of shifting selective pressures from competing with other community members to competing with other individuals within a population over finite resources. As such, body shape can also be divergent compared to closely related mainland counterparts due to adaptation to local ecogeographic pressures. Skeletal traits of organisms need to be interpreted in relation to their migratory journeys and adaptation to local ecogeographic pressures within the island. For humans, contextualizing these variables with cultural and behavioral characteristics is imperative to understand a body size response within a sociocultural omnivorous niche.

An investigation of factors influencing erythrocyte morphology of red-backed salamanders (Plethodon cinereus)

2009 ◽  
Vol 59 (2) ◽  
pp. 201-209 ◽  
Author(s):  
John Maerz ◽  
Joseph Milanovich ◽  
Andrew Davis ◽  
Jayna DeVore
Keyword(s):  
Body Size ◽  
Body Condition ◽  
Oxygen Demand ◽  
Plethodon Cinereus ◽  
Future Research ◽  
Health State ◽  
Erythrocyte Morphology ◽  
Size And Shape ◽  
Plethodontid Salamanders ◽  
Body Sizes

AbstractAmphibians have long been known to display wide variation in erythrocyte morphology across species, but within species there has been little attention given to individual variation in red blood cell morphology. We captured 49 red-backed salamanders (Plethodon cinereus) from central Pennsylvania, USA and used image analysis procedures to measure erythrocyte morphology (size and shape) on blood smears made from all individuals. We then statistically examined whether variation in snout-vent-length, sex, tail loss, or capture location influenced these cell variables. Only snout-vent-length affected erythrocyte size and shape, with increasing body sizes associated with increasing cell areas and increasingly rounder cells. Further, erythrocyte shape was also associated with a measure of body condition that was corrected for body size, such that individuals with high body condition scores had rounder cells. Given the oxygen-carrying role of erythrocytes in all vertebrates, we suspect this discovery is related to size-related changes in oxygen demand, since total oxygen consumption increases with body size in an allometric manner. While our results warrant further investigation to understand the mechanism, the association we found between cell roundness and both body size and condition nevertheless indicates this parameter could be used to assess the health state of plethodontid salamanders in future research, provided non-destructive sampling is employed. Our results also underscore the value of hematological investigations in the study of animal biology.

Changing invaders: trends of gigantism in insular introduced rats

2018 ◽  
Vol 45 (3) ◽  
pp. 203-211 ◽  
Author(s):  
ALEXANDRA A.E. VAN DER GEER
Keyword(s):  
Body Size ◽  
Solomon Islands ◽  
Mammalian Species ◽  
Island Rule ◽  
Island Populations ◽  
Island Group ◽  
Body Sizes ◽  
History Of ◽  
Analyse Data ◽  
Insular Populations

SUMMARYThe degree and direction of morphological change in invasive species with a long history of introduction are insufficiently known for a larger scale than the archipelago or island group. Here, I analyse data for 105 island populations of Polynesian rats,Rattus exulans, covering the entirety of Oceania and Wallacea to test whether body size differs in insular populations and, if so, what biotic and abiotic features are correlated with it. All insular populations of this rat, except one, exhibit body sizes up to twice the size of their mainland conspecifics. Body size of insular populations is positively correlated with latitude, consistent with thermoregulatory predictions based on Bergmann's rule. Body size is negatively correlated with number of co-occurring mammalian species, confirming an ecological hypothesis of the island rule. The largest rats are found in the temperate zone of New Zealand, as well as on mammalian species-poor islands of Polynesia and the Solomon Islands. Carnivory in the form of predation on nesting seabird colonies seems to promote 1.4- to 1.9-fold body size increases.

scholarly journals Warming waters beget smaller fish: evidence for reduced size and altered morphology in a desert fish following anthropogenic temperature change

2019 ◽  
Vol 15 (10) ◽  
pp. 20190518 ◽  
Author(s):  
Sean C. Lema ◽  
Samantha L. Bock ◽  
Morgan M. Malley ◽  
Emma A. Elkins
Keyword(s):  
Body Size ◽  
Morphological Changes ◽  
Global Climate ◽  
Reaction Rates ◽  
Metabolic Energy ◽  
Body Depth ◽  
Reduced Body ◽  
Energy Demands ◽  
Ecological Changes ◽  
Body Sizes

Poikilothermic organisms are predicted to show reduced body sizes as they experience warming environments under a changing global climate. Such a shrinking of size is expected under scenarios where rising temperatures increase cellular reaction rates and basal metabolic energy demands, therein requiring limited energy to be shifted from growth. Here, we provide evidence that the ecological changes associated with warming may not only lead to shrinking body size but also trigger shifts in morphology. We documented 33.4 and 39.0% declines in body mass and 7.2 and 7.6% reductions in length for males and females, respectively, in a wild population of Amargosa pupfish, Cyprinodon nevadensis amargosae , following an abrupt anthropogenically driven temperature increase. That reduction in size was accompanied by the partial or complete loss of paired pelvic fins in approximately 34% of the population, a morphological change concomitant with altered body dimensions including head size and body depth. These observations confirm that increasing temperatures can reduce body size under some ecological scenarios and highlight how human-induced environmental warming may also trigger morphological changes with potential relevance for fitness.

scholarly journals Reduced body sizes in climate-impacted Borneo moth assemblages are primarily explained by range shifts

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chung-Huey Wu ◽  
Jeremy D. Holloway ◽  
Jane K. Hill ◽  
Chris D. Thomas ◽  
I-Ching Chen ◽  
...  
Keyword(s):  
Body Size ◽  
Climate Warming ◽  
Species Range ◽  
Range Shifts ◽  
Community Size ◽  
Relative Contribution ◽  
Reduced Body ◽  
Body Sizes ◽  
High Elevations ◽  
Length Reduction

Abstract Both community composition changes due to species redistribution and within-species size shifts may alter body-size structures under climate warming. Here we assess the relative contribution of these processes in community-level body-size changes in tropical moth assemblages that moved uphill during a period of warming. Based on resurvey data for seven assemblages of geometrid moths (>8000 individuals) on Mt. Kinabalu, Borneo, in 1965 and 2007, we show significant wing-length reduction (mean shrinkage of 1.3% per species). Range shifts explain most size restructuring, due to uphill shifts of relatively small species, especially at high elevations. Overall, mean forewing length shrank by ca. 5%, much of which is accounted for by species range boundary shifts (3.9%), followed by within-boundary distribution changes (0.5%), and within-species size shrinkage (0.6%). We conclude that the effects of range shifting predominate, but considering species physiological responses is also important for understanding community size reorganization under climate warming.

A new, diminutive species ofCatopsalis(Mammalia, Multituberculata, Taeniolabidoidea) from the early Paleocene of southwestern Alberta, Canada

2018 ◽  
Vol 92 (5) ◽  
pp. 896-910
Author(s):  
Craig S. Scott ◽  
Anne Weil ◽  
Jessica M. Theodor
Keyword(s):  
New Species ◽  
Body Size ◽  
Body Mass ◽  
North American ◽  
Phylogenetic Position ◽  
Early Paleocene ◽  
Body Sizes ◽  
History Of ◽  
American Clade ◽  
A New Species

AbstractMultituberculates were among the most taxonomically diverse mammals of the early Paleocene, having survived the catastrophic Cretaceous-Paleogene mass extinction and radiating soon thereafter. Although their evolution during the early Paleocene saw the advent of increasingly specialized dentitions, multituberculates generally remained small, rarely exceeding body sizes greater than those of extant rabbits. A conspicuous exception is the Taeniolabidoidea, a primarily North American clade whose members include the largest multituberculates yet discovered. Taeniolabidoidea includes several genera, with one of these,Catopsalis, being speciose and geographically wide ranging. Until recently, the chronological succession ofCatopsalisappeared to document a trend of increasing body size. We report here on a new species ofCatopsalisfrom the early Paleocene of Alberta that violates this trend and suggests that the evolutionary history ofCatopsalisis considerably more complex.Catopsalis kakwanew species is not only the smallest species ofCatopsalis, but is the smallest taeniolabidoid so far discovered, with an estimated body mass between 400 g and 660 g. In contrast to previous studies, we used recently proposed regressions based on lower cheek tooth row length to estimate body masses for North American taeniolabidoids. Our results propose more modest body mass estimates, particularly for the largest taeniolabidoids. The occurrence ofC.kakwan. sp. in the late early Paleocene implies either a significant ghost lineage, or reversal of several characters, including body size, during the latter part of the early Paleocene; the more likely of these scenarios must await a better understanding of the phylogenetic position ofC.kakwan. sp.UUID:http://zoobank.org/66d85345-49b8-4a46-ba6e-a4d4369cb3e0urn:lsid:zoobank.org:pub:AF7A5659-9068-4F2F-A6EC-5522A2BBA4CB

Reduced Body Size and Shape-Related Symptoms in Young Adults Born Preterm with Very Low Birth Weight: Helsinki Study of Very Low Birth Weight Adults

2010 ◽  
Vol 157 (3) ◽  
pp. 421-427.e1 ◽  
Author(s):  
Karoliina Wehkalampi ◽  
Petteri Hovi ◽  
Sonja Strang-Karlsson ◽  
Katri Räikkönen ◽  
Anu-Katriina Pesonen ◽  
...  
Keyword(s):  
Young Adults ◽  
Body Size ◽  
Birth Weight ◽  
Low Birth Weight ◽  
Very Low Birth Weight ◽  
Size And Shape ◽  
Reduced Body

scholarly journals Taxonomy of the winged popcorn flower: Cryptantha pterocarya (Boraginaceae)

Phytotaxa ◽  
2016 ◽  
Vol 253 (2) ◽  
pp. 97 ◽  
Author(s):  
MAKENZIE E. MABRY ◽  
REGINA A. DOWDY ◽  
LEE M. SIMPSON ◽  
JON P. REBMAN ◽  
MICHAEL G. SIMPSON
Keyword(s):  
Body Size ◽  
Phylogenetic Relationships ◽  
Morphological Characters ◽  
Geographic Range ◽  
Wing Morphology ◽  
Type Specimens ◽  
Size And Shape ◽  
Molecular Studies ◽  
History Of ◽  
Voucher Specimens

Cryptantha pterocarya (Boraginaceae), the winged nut popcorn flower, is distinguished in part by nutlets with marginal, typically lobed wings. Four varieties of this species have been accepted in recent treatments: vars. cycloptera, pterocarya, purpusii, and stenoloba. We tested the taxonomic discreteness, degree of variation, and geographic range of these varieties of C. pterocarya by examining material from numerous voucher specimens. We quantified differences among specimens by measuring or calculating twenty features of the corolla and fruit, the latter focusing on mature (fruiting) calyx and nutlet characteristics. Type specimens of all four varieties were examined and quantified, and all specimens were georeferenced and mapped. From our observations and measurements, we recognize two new morphological forms in the complex, termed the “pseudocycloptera” form and the “truncata” form. The “pseudocycloptera” form is similar to var. pterocarya but is homomorphic, with all four nutlets winged. The “truncata” form is similar to var. cycloptera, but is heteromorphic, with the odd nutlet having a reduced basal wing (somewhat truncate in shape) and having a slightly reduced gynobase stipe. We conclude that C. p. var. pterocarya, var. purpusii, and var. stenoloba should continue to be recognized as taxa at that rank. The “pseudocycloptera” form, although generally morphologically discrete in nutlet heteromophism, shows some intergradation, even within a specimen, of the typical form of C. p. var. pterocarya and exhibits no clear geographic discontinuity; it should thus be recognized as a homomorphic form of that taxon, which we formally name forma pseudocycloptera. Variety purpusii should continue to be recognized at that rank given its variation in nutlet wing morphology but with continuity in geographic range. Variety stenoloba should also continue to be recognized at this rank given its distinctive calyx and nutlet body size and shape, but having a quite limited geographic range. We conclude that what has been most commonly recognized as C. pterocarya var. cycloptera should be resurrected to the rank of species, as C. cycloptera, because of the distinctiveness of this taxon in three, discrete morphological characters, one of which (gynobase stipe) was previously undescribed. The “truncata” form, which shows some intergradation with C. cycloptera and lacks geographic discontinuity, should be recognized as a heteromorphic form of C. cycloptera, which we formally name forma truncata. A revised key is proposed to better accommodate the identity of these taxa and forms. We hope that future molecular studies will elucidate the phylogenetic relationships, character evolution, and geographic history of this interesting taxonomic complex.

Ontogeny and phylogeny of the dorsal cup in calceocrinid crinoids

1990 ◽  
Vol 64 (2) ◽  
pp. 300-318 ◽  
Author(s):  
James C. Brower
Keyword(s):  
Body Size ◽  
Allometric Equations ◽  
Plate Structure ◽  
Adult Body Size ◽  
Size And Shape ◽  
Dominant Pattern ◽  
Adult Body ◽  
Primitive Species ◽  
Body Sizes

The dorsal cups of 17 calceocrinid species illustrate the relations between ontogeny and phylogeny for this unique family. Paedomorphosis in conjunction with increasing adult body size comprises the dominant pattern. During evolution, the plate structure of the dorsal cup was rearranged so that the hinge of advanced crinoids resembles the juvenile configuration of more primitive species. Consideration of allometric equations dealing with the size and shape of the dorsal cup and hinge suggests that most changes were caused by displacements of the initial intercepts and offsets of timing in development. The growth of the hinge moment of typical taxa produces hinges that are functionally equivalent in adult crinoids of different body sizes.

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