Convergence, parallelism, and function of extreme parietal callus in diverse groups of Cenozoic Gastropoda

Paleobiology ◽  
2020 ◽  
pp. 1-26
Author(s):  
Carlie Pietsch ◽  
Brendan M. Anderson ◽  
Lauren M. Maistros ◽  
Ethan C. Padalino ◽  
Warren D. Allmon
Keyword(s):  
Body Size ◽  
Functional Ecology ◽  
Low Density ◽  
Shell Microstructure ◽  
Shell Surface ◽  
Microscopy Imaging ◽  
Living Species ◽  
Essential Contribution ◽  
And Function ◽  
Diverse Groups

Abstract We use scanning electron microscopy imaging to examine the shell microstructure of fossil and living species in five families of caenogastropods (Strombidae, Volutidae, Olividae, Pseudolividae, and Ancillariidae) to determine whether parallel or convergent evolution is responsible for the development of a unique caenogastropod trait, the extreme parietal callus (EPC). The EPC is defined as a substantial thickening of both the spire callus and the callus on the ventral shell surface such that it covers 50% or more of the surface. Caenogastropods as a whole construct the EPC convergently, using a variety of low-density, poorly organized microstructures that are otherwise uncommon in caenogastropod non-callus shell construction. Within clades, however, we see evidence for parallelism in decreased regulation in both the shell and callus microstructure. Low-density and poorly ordered microstructure—such as used for the EPC—uses less organic scaffolding and is less energetically expensive than normal shell microstructure. This suggests the EPC functions to rapidly and inexpensively increase shell thickness and overall body size. Tests of functional ecology suggest that the EPC might function both to defend against crushing predation through increased body size and dissipation of forces while aiding in shell orientation of highly mobile gastropods. These interpretations hinge on the current phylogenetic placement of caenogastropod families, emphasizing the essential contribution of phylogeny when interpreting homoplasy.

scholarly journals Functional ecological convergence between the thylacine and small prey-focused canids

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Douglass S. Rovinsky ◽  
Alistair R. Evans ◽  
Justin W. Adams
Keyword(s):  
Body Mass ◽  
Prey Size ◽  
Functional Ecology ◽  
Fundamental Aspect ◽  
South American ◽  
Form And Function ◽  
Living Species ◽  
Superficial Similarity ◽  
Degree Of Convergence ◽  
And Function

Abstract Background Morphological convergence is a fundamental aspect of evolution, allowing for inference of the biology and ecology of extinct species by comparison with the form and function of living species as analogues. The thylacine (Thylacinus cynocephalus), the iconic recently extinct marsupial, is considered a classic example of convergent evolution with the distantly related placental wolf or dog, though almost nothing is actually known regarding its ecology. This lack of data leads to questions regarding the degree of convergence with, and the similarity of, the functional ecology of the thylacine and the wolf/dog. Here, we examined the cranium of the thylacine using 3D geometric morphometrics and two quantitative tests of convergence to more precisely determine convergent analogues, within a phylogenetically informed dataset of 56 comparative species across 12 families of marsupial and placental faunivorous mammals. Using this dataset, we investigated patterns of correlation between cranial shape and diet, phylogeny, and relative prey size across these terrestrial faunivores. Results We find a correlation between cranial, facial, and neurocranial shape and the ratio of prey-to-predator body mass, though neurocranial shape may not correlate with prey size within marsupials. The thylacine was found to group with predators that routinely take prey smaller than 45% of their own body mass, not with predators that take subequal-sized or larger prey. Both convergence tests find significant levels of convergence between the thylacine and the African jackals and South American ‘foxes’, with lesser support for the coyote and red fox. We find little support for convergence between the thylacine and the wolf or dog. Conclusions Our study finds little support for a wolf/dog-like functional ecology in the thylacine, with it instead being most similar to mid-sized canids such as African jackals and South American ‘foxes’ that mainly take prey less than half their size. This work suggests that concepts of convergence should extend beyond superficial similarity, and broader comparisons can lead to false interpretations of functional ecology. The thylacine was a predator of small to mid-sized prey, not a big-game specialist like the placental wolf.

Effects of population density on female and male burrow characteristics in the fiddler crab, Uca bengali Crane, 1975

Crustaceana ◽  
2015 ◽  
Vol 88 (12-14) ◽  
pp. 1283-1299 ◽  
Author(s):  
Fahmida Wazed Tina ◽  
Mullica Jaroensutasinee ◽  
Krisanadej Jaroensutasinee
Keyword(s):  
Body Size ◽  
Population Density ◽  
Fiddler Crab ◽  
High Density ◽  
The Other ◽  
Low Density ◽  
Density Effects ◽  
Egg Incubation ◽  
Other Hand ◽  
Males And Females

We examined the effects of population density on body size and burrow characteristics ofUca bengaliCrane, 1975. We predicted that (1) males in high-density areas (HD) should be larger in size and build higher quality burrows than males in low-density areas (LD), and (2) HD females should be larger in size, but build lower quality burrows than LD females, as HD females can find higher numbers of good quality male burrows around them for breeding and egg incubation. Our results showed that males and females in HD were larger in size than those in LD. Since HD males were larger in size, they built higher quality burrows than males in LD. On the other hand, even though LD females were smaller in size than HD ones, they built higher quality burrows than HD females. Our results thus indicate that density effects both body size and burrow characteristics.

The non-linear relationship between body size and function in parrotfishes

Coral Reefs ◽  
2008 ◽  
Vol 27 (4) ◽  
pp. 967-974 ◽  
Author(s):  
J. Lokrantz ◽  
M. Nyström ◽  
M. Thyresson ◽  
C. Johansson
Keyword(s):  
Body Size ◽  
Linear Relationship ◽  
Non Linear ◽  
And Function

Functional diversity of ISWI complexes

2004 ◽  
Vol 82 (4) ◽  
pp. 482-489 ◽  
Author(s):  
Sara S Dirscherl ◽  
Jocelyn E Krebs
Keyword(s):  
Chromatin Remodeling ◽  
Catalytic Core ◽  
Chromatin Remodelers ◽  
Form And Function ◽  
Curr Opin Cell Biol ◽  
Chromatid Cohesion ◽  
Chromatin Remodeling Complexes ◽  
And Function ◽  
Diverse Groups ◽  
Nuclear Processes

The yeast SWI/SNF ATP-dependent chromatin remodeling complex was first identified and characterized over 10 years ago (F. Winston and M. Carlson. 1992. Trends Genet. 8: 387–391.) Since then, the number of distinct ATP-dependent chromatin remodeling complexes and the variety of roles they play in nuclear processes have become dizzying (J.A. Martens and F. Winston. 2003. Curr. Opin. Genet. Dev. 13: 136–142; A. Vacquero et al. 2003. Sci. Aging Knowledge Environ. 2003: RE4) — and that does not even include the companion suite of histone modifying enzymes, which exhibit a comparable diversity in both number of complexes and variety of functions (M.J. Carrozza et al. 2003. Trends Genet. 19: 321–329; W. Fischle et al. 2003. Curr. Opin. Cell Biol. 15: 172–183; M. Iizuka and M.M. Smith. 2003. Curr. Opin. Genet. Dev. 13: 1529–1539). This vast complexity is hardly surprising, given that all nuclear processes that involve DNA — transcription, replication, repair, recombination, sister chromatid cohesion, etc. — must all occur in the context of chromatin. The SWI/SNF-related ATP-dependent remodelers are divided into a number of subfamilies, all related by the SWI2/SNF2 ATPase at their catalytic core. In nearly every species where researchers have looked for them, one or more members of each subfamily have been identified. Even the budding yeast, with its comparatively small genome, contains eight different chromatin remodelers in five different subfamilies. This review will focus on just one subfamily, the Imitation Switch (ISWI) family, which is proving to be one of the most diverse groups of chromatin remodelers in both form and function.

The role of Spadefoot Toad tadpoles in wetland trophic structure as influenced by environmental and morphological factors

2011 ◽  
Vol 89 (1) ◽  
pp. 47-59 ◽  
Author(s):  
D. M. Ghioca-Robrecht ◽  
L. M. Smith
Keyword(s):  
Body Size ◽  
Great Plains ◽  
Trophic Structure ◽  
Trophic Levels ◽  
Wetland Ecosystems ◽  
Southern Great Plains ◽  
Larval Amphibians ◽  
Spadefoot Toad ◽  
Spea Bombifrons ◽  
And Function

Larval amphibians reach high densities in playa wetlands in the Southern Great Plains (SGP), USA, and thus may influence the entire structure and function of these ecosystems. We investigated whether both carnivorous and omnivorous morphotypes of Spadefoot Toad tadpoles (New Mexico Spadefoot, Spea multiplicata (Cope, 1863), and Plains Spadefoot, Spea bombifrons (Cope, 1863)) would exhibit a macrophagous feeding behavior that would allow them to occupy several trophic levels in playas. We also compared tadpole diets and foregut widths as influenced by the land use surrounding playas (cultivated versus grassland watersheds), year (dry versus wet year), and body size (snout-to-vent length). Tadpole diets were dominated by detritus and diatoms and tadpole foreguts increased with body size. Generally, more arthropods and less cyanobacteria were found in Spea tadpole diets as tadpoles grew larger, suggesting they influence different trophic levels with age. Foreguts were wider in carnivores than omnivores, suggesting carnivores had increased ability to ingest larger prey. Also, omnivores had wider foreguts in cropland than grassland playas, suggesting they ingest larger food items in cropland playas. From estimates of the amounts of invertebrates, detritus, and algae consumed by Spea tadpoles, we demonstrate that these larvae influence the entire trophic structure of wetland ecosystems.

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