3D Digitization in Functional Morphology: Where is the Point of Diminishing Returns?

Integrative and Comparative Biology, Journal Year: 2019, Volume and Issue: 59(3), P. 656 - 668

Published: June 5, 2019

Modern computational and imaging methods are revolutionizing the fields of comparative morphology, biomechanics, ecomorphology. In particular, tools such as X-ray micro computed tomography (µCT) diffusible iodine-based contrast enhanced CT allow observing measuring small and/or otherwise inaccessible anatomical structures, creating highly accurate three-dimensional (3D) renditions that can be used in biomechanical modeling tests functional or evolutionary hypotheses. But, do larger datasets generated through 3D digitization always confer greater power to uncover patterns, when compared with more traditional methodologies? And, if so, why? Here, we advantages challenges using data via versus (2D) approaches study skull macroevolution feeding morphology bats. First, test for effect dimensionality landmark number on inferences adaptive shifts during cranial evolution by contrasting results from 2D geometric morphometric bat crania. We find sharp differences between some (xy, yz, ventral, frontal), which appear primarily driven loss critical dimensions morphological variation rather than landmarks. Second, examine accuracy precision among predictive models bite force comparing three lever differ sources muscle data. a model relies µCT scans partly derived diceCT is slightly based photographs fully dissections. However, benefit diceCT-informed modest given effort it currently takes virtually dissect muscles scans. By modern tools, illustrate why may preferable over data, vice versa, how different methodologies complement each other analyses function evolution.

Language: Английский

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Sexual dimorphism in the electric knifefish, Gymnorhamphichthys rondoni (Rhamphichthyidae: Gymnotiformes)

Acta Amazonica, Journal Year: 2019, Volume and Issue: 49(3), P. 213 - 220

Published: Aug. 16, 2019

ABSTRACT Sexual dimorfism refers to morphological differences between males and females of a species. It may be result different selection pressures acting on either or both sexes occur in any sexually-reproducing dioecious species, including fishes. We analyzed 63 adult Gymnorhamphichthys rondoni (Gymnotiformes) collected by us deposited museum collections. Sex was identified through abdominal dissection. measured length from snout posterior end anal-fin, anal-fin length, distance anus origin, genital papilla body width at beginning head length. Morphometric data submitted Principal Component Analysis (PCA) grouped according variables related size (along the first component) height along second third components. Females were larger than males, whereas had proportionally heads higher bodies females. The urogenital showed shape, relative position body. female elongated horizontally, that located vertical line below eye, while vertically operculum. To our knowledge, this is recorded case sexual dimorphism species Rhamphichthyidae, condition now known all currently recognized families Gymnotiformes.

Language: Английский

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Patterns of diversification and phylogenetic structure in the dorsolateral head musculature of Neotropical electric eels (Ostariophysi: Gymnotiformes), with a myological synonymy

Neotropical Ichthyology, Journal Year: 2022, Volume and Issue: 20(1)

Published: Jan. 1, 2022

Abstract The present study offers a broad comparative analysis of the dorsolateral head musculature in Gymnotiformes, with detailed descriptions and illustrations muscles 83 species representing combined all valid genera. Results permit assessment primary homologies taxonomically-relevant variation across order. This provides basis for myological synonymy, which organizes 33 previously proposed names 15 recognized muscles. Morphological derived from was coded into 56 characters. When analyzed isolation, that set characters results Gymnotidae as sister group remaining gymnotiforms, other currently families monophyletic groups. In second analysis, were concatenated phenotypic matrix. reveal new synapomorphies nearly taxonomic categories within Gymnotiformes. A Partitioned Bremer Support (PBS) used to asses significance myology elucidating phylogenetic relationships. PBS values show strongly non-uniform distributions on tree, positive scores skewed towards more inclusive taxa, negative concentrated less clades. Our provide background future studies biomechanical constraints evolved early stages gymnotiform evolution.

Language: Английский

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Mosaic Evolution of Craniofacial Morphologies in Ghost Electric Fishes (Gymnotiformes: Apteronotidae)

Ichthyology & Herpetology, Journal Year: 2022, Volume and Issue: 110(2)

Published: May 26, 2022

Ghost electric knifefishes (Gymnotiformes: Apteronotidae) are a dominant component of the species diversity and biomass large lowland rivers in Greater Amazonia, including 77 that exhibit diverse craniofacial morphologies associated with trophic secondary sexual traits. Here we use open-source computed micro-tomography (µCT) scans to generate 3D reconstructions for majority apteronotid almost all valid genera, geometric morphometric phylogenetic analyses explore patterns skull evolution. As most vertebrates, principal 1 (PC1) summarizes variance from brachycephalic dolichocephalic morphologies, previously described as heterocephaly, PC2 recurved (upturned) decurved (downturned) snout here heterorhynchy. Phylomorphospace traitogram found instances both convergent divergent evolution along first two PC axes, well preponderance clades characterized by morphological stasis or conservatism. Certain phenotypic combinations predominate among clades, elongated-downturned snouts foreshortened-upturned snouts, while other not observed, elongated-upturned foreshortened-downturned snouts. These results highlight power morphometrics study indicate developmental functional constraints phenotypes an ecologically clade riverine Amazonian fishes.

Language: Английский

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Patterns of Body Shape Diversity and Evolution in Intertidal and Subtidal Lineages of Combtooth Blennies (Blenniidae)

Integrative Organismal Biology, Journal Year: 2021, Volume and Issue: 3(1)

Published: Jan. 1, 2021

Abstract Marine intertidal zones can be harsher and more dynamic than bordering subtidal zones, with extreme temporally variable turbulence, water velocity, salinity, temperature, dissolved oxygen levels. Contrasting environmental conditions ecological opportunities in versus habitats may generate differing patterns of morphological diversity. In this study we used phylogenetic comparative methods, measurements body length, two-dimensional landmarks to characterize shape size diversity combtooth blennies (Ovalentaria: Blenniidae) test for differences between intertidal, subtidal, supralittoral zones. We found that have significantly higher disparity occupy a region morphospace three times larger lineages. The was almost entirely contained within the morphospace, showing did not evolve unique shapes. no significant tidal correlations zone or zone, convergence associated zone. Our findings suggest subset blenny shapes are suitable life both habitats. Many species regions exhibit distinct microhabitat use, which suggests environments promoted diversification via evolutionary transitions. contrast, limited due strong selective pressures constrained evolution filtering prevented colonization by certain

Language: Английский

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Ontogenetic growth in the crania ofExaeretodon argentinus(Synapsida: Cynodontia) captures a dietary shift

PeerJ, Journal Year: 2022, Volume and Issue: 10, P. e14196 - e14196

Published: Oct. 21, 2022

Background An ontogenetic niche shift in vertebrates is a common occurrence where ecology shifts with morphological changes throughout growth. How over vertebrate’s lifetime often reconstructed extant species—by combining observational and skeletal data from growth series of the same species—because interactions between organisms their environment can be observed directly. However, reconstructing using extinct difficult requires well-sampled series, specimens relatively complete preservation, easily observable traits associated ecologies suspected to change growth, such as diet. Methods To reconstruct ecological stem-mammal, we describe dietary crania large-bodied (∼2 m length) herbivorous form, Exaeretodon argentinus (Cynodontia: Traversodontidae) Late Triassic Ischigualasto Formation, San Juan, Argentina. Nearly all were deformed by taphonomic processes, so allometric slope generalized linear mixed effects model distortion random effect. Results Under model, find that E. reduced relative length palate, postcanine orbits, basicranium, expanded temporal region height zygomatic arch. The relationship arch total skull approximate rate for feeding musculature. Based on higher slope, zygoma growing faster than region. may suggest smaller individuals had crushing-dominated style transitioned into chewing-dominated larger individuals, suggesting possible faunivory more plant-dominated Dietary differentiation development further supported an increase sutural complexity orientation microwear anisotropy small large . A developmental transition reflective across Gomphodontia, wherein earliest-diverging species are inferred omnivorous well-nested traversodontids herbivorous, potentially immature Traversodontidae plesiomorphic clade.

Language: Английский

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Electrocommunication signals and aggressive behavior vary among male morphs in an apteronotid fish,Compsaraia samueli

Journal of Experimental Biology, Journal Year: 2022, Volume and Issue: 225(12)

Published: May 23, 2022

Within-species variation in male morphology is common among vertebrates and often characterized by dramatic differences behavior hormonal profiles. Males with divergent morphs also use communication signals a status-dependent way. Weakly electric knifefish are an excellent system for studying its control. Knifefish transiently modulate the frequency of their organ discharge (EOD) during social encounters to produce chirps rises. In Compsaraia samueli, males vary extensively jaw length. EODs modulations (chirps rises) have never been investigated this species, so it unclear whether length related function these signals. We used three behavioral assays analyze EOD C. samueli: (1) artificial playbacks, (2) relatively brief, live agonistic dyadic encounters, (3) long-term overnight recordings. measured circulating levels two androgens, 11-ketotestosterone testosterone. Chirp structure varied within across individuals response playback, but was unrelated longer jaws were more dominant interactions. Chirps rises correlated preceded attacks regardless status, suggesting aggression. longer-term interactions, chirp rate declined after 1 week pairing, morphology. Levels androgens low not predictive or signal parameters. These results suggest that linked outcomes non-breeding contests.

Language: Английский

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Annotated checklist of the primarily freshwater fishes of Guyana

Proceedings of the Academy of Natural Sciences of Philadelphia, Journal Year: 2022, Volume and Issue: 168(1)

Published: Nov. 1, 2022

Guyana, located in northern South America north of Brazil between Venezuela and Suriname, includes portions the Orinoco, Amazon, Courantyne river basins, a majority Essequibo River Basin, all Berbice Demerara basins. Partly as consequence historical contemporary drainage complexity, Guyana has remarkably diverse freshwater fish fauna. Here, we compile first comprehensive list Guyana's fishes, totaling some 657 species-level taxa (97 records, 117 endemics at least three introduced species), based on photographic published reports, over 145,000 type non-type specimens 29 museum collections. The IUCN conservation status for each species is provided. We separately an additional 151 undocumented that are possibly or likely present their adjacent distributions either Orinoco Delta Suriname. largest holdings specimen vouchers frozen tissues from housed Royal Ontario Museum, Toronto (ROM), Auburn University (AUM), Michigan Museum Zoology, Ann Arbor (UMMZ), Academy Natural Sciences Drexel University, Philadelphia (ANSP). Additional important collections Guyanese fishes deposited Centre Study Biological Diversity, Georgetown, (CSBD), Field History, Chicago (FMNH), Illinois History Survey, Champaign (INHS), London (NHMUK, formerly BMNH), Oregon State Corvallis (OS), US National Washington (USNM). Despite many have been made still lack vouchered tissues, more require formal description.

Language: Английский

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New Method for Rapid 3D Reconstruction of Semi-Transparent Underwater Animals and Structures

Integrative Organismal Biology, Journal Year: 2023, Volume and Issue: 5(1)

Published: Jan. 1, 2023

Synopsis Morphological features are the primary identifying properties of most animals and key to many comparative physiological studies, yet current techniques for preservation documentation soft-bodied marine limited in terms quality accessibility. Digital records can complement physical specimens, with a wide array applications ranging from species description kinematics modeling, but options lacking creating models semi-transparent underwater animals. We developed lab-based technique that live-scan semi-transparent, submerged animals, objects within seconds. To demonstrate method, we generated full three-dimensional reconstructions (3DRs) an object known dimensions verification, as well two live animals—a siphonophore amphipod—allowing detailed measurements on each. Techniques like these pave way faster data capture, integrative quantitative approaches, more accessible collections fragile rare biological samples.

Language: Английский

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Phylogenetic structure of body shape in a diverse inland ichthyofauna

Scientific Reports, Journal Year: 2023, Volume and Issue: 13(1)

Published: Nov. 25, 2023

Abstract Body shape is a fundamental metric of animal diversity affecting critical behavioral and ecological dynamics conservation status, yet previously available methods capture only fraction total body-shape variance. Here we use structure-from-motion (SFM) 3D photogrammetry to generate digital models adult fishes from the Lower Mississippi Basin, one most diverse temperate-zone freshwater faunas on Earth, geometric morphometrics morphologically distinct variables, interpreting principal components as growth fields. The mean body in this fauna resembles plesiomorphic teleost fishes, major dimensions disparity are similar those other fish worldwide. Major patterns structured by phylogeny, with nested clades occupying portions morphospace, morphospace occupied multiple clades, clade (Acanthomorpha) accounting for over half In contrast previous studies, variance depth (59.4%) structures overall more than does length (31.1%), while width accounts non-trivial (9.5%) amount disparity.

Language: Английский

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