scholarly journals Geometric Morphometric Analyses Support Incorporating the Goshen Point Type into Plainview

2019 ◽  
Vol 85 (1) ◽  
pp. 171-181 ◽  
Author(s):  
Briggs Buchanan ◽  
Mark Collard ◽  
Michael J. O'Brien
Keyword(s):  
Recent Work ◽  
Social Dynamics ◽  
Spatiotemporal Variation ◽  
Single Type ◽  
Geometric Morphometric ◽  
Morphometric Analyses ◽  
Morphometric Methods ◽  
Point Type

Recent work has demonstrated that Goshen points overlap in time with another group of unfluted lanceolate points from the Plains, Plainview points. This has raised the question of whether the two types should be kept separate or consolidated into a single type. We sought to resolve this issue by applying geometric morphometric methods to a sample of points from well-documented Goshen and Plainview assemblages. We found that their shapes were statistically indistinguishable, which indicates that Goshen and Plainview points should be assigned to the same type. Because Plainview points were recognized before Goshen points, it is the latter type name that should be dropped. Sinking Goshen into Plainview allows us to move beyond taxonomic issues and toward understanding both the spatiotemporal variation that exists among Plainview assemblages and what it can tell us about the adaptations and social dynamics of Plainview groups.

scholarly journals Arothron: An R package for geometric morphometric methods and virtual anthropology applications

2021 ◽  
Author(s):  
Profico Antonio ◽  
Buzi Costantino ◽  
Castiglione Silvia ◽  
Melchionna Marina ◽  
Piras Paolo ◽  
...  
Keyword(s):  
R Package ◽  
Geometric Morphometric ◽  
Morphometric Methods ◽  
Virtual Anthropology

scholarly journals Comparing skull formation of the Hungarian (Hortobágy) Zackel sheep breed by geometrics morphometrics

2015 ◽  
pp. 29-33
Author(s):  
Zsuzsanna Csóri ◽  
András Gáspárdy ◽  
András Jávor
Keyword(s):  
Morphological Changes ◽  
Time Change ◽  
Carpathian Basin ◽  
Sheep Breed ◽  
Geometric Morphometric ◽  
The Past ◽  
Morphometric Methods ◽  
Skull Formation ◽  
Over Time

This work seeks to explore the morphological changes of the Hungarian (Hortobágy) Zackel sheep's skull, which occurred in the past 50–70 years. In this study, we compared individuals skull forms by geometric morphometric methods. The origin of the breed is not known, we do not know when entering the Carpathian Basin. Therefore, the comparison involved the only known early archaeological findings. We have shown that there is no difference between each period colour variations, but over time change has occurred in the skull formation of the breed.

scholarly journals Morphological diversity in tenrecs (Afrosoricida, Tenrecidae): comparing tenrec skull diversity to their closest relatives

2015 ◽  
Author(s):  
Sive Finlay ◽  
Natalie Cooper
Keyword(s):  
Quantitative Analysis ◽  
Quantitative Methods ◽  
Morphological Diversity ◽  
Lateral View ◽  
Ecological Niches ◽  
Diverse Group ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Morphometric Analyses ◽  
The Family

Morphological diversity is often studied qualitatively. However, to truly understand the evolution of exceptional diversity, it is important to take a quantitative approach instead of relying on subjective, qualitative assessments. Here, we present a quantitative analysis of morphological diversity in a Family of small mammals, the tenrecs (Afrosoricida, Tenrecidae). Tenrecs are often cited as an example of an exceptionally morphologically diverse group. However, this assumption has not been tested quantitatively. We use geometric morphometric analyses of skull shape to test whether tenrecs are more morphologically diverse than their closest relatives, the golden moles (Afrosoricida, Chrysochloridae). Tenrecs occupy a wider range of ecological niches than golden moles so we predict that they will be more morphologically diverse. Contrary to our expectations, We find that tenrec skulls are only more morphologically diverse than golden moles when measured in lateral view. Furthermore, similarities among the species-rich Microgale tenrec Genus appear to mask higher morphological diversity in the rest of the Family. These results reveal new insights into the morphological diversity of tenrecs and highlight the importance of using quantitative methods to test qualitative assumptions about patterns of morphological diversity.

On the morphospace of eurypterine sea scorpions

2021 ◽  
pp. 1-6
Author(s):  
Russell D. C. BICKNELL ◽  
Lisa AMATI
Keyword(s):  
New Taxa ◽  
Compound Eye ◽  
Developmental Changes ◽  
Apex Predators ◽  
Geometric Morphometric ◽  
Eye Morphology ◽  
Morphometric Analyses ◽  
Ontogenetic Trajectories ◽  
Landmark Analyses ◽  
Shape Data

ABSTRACT Eurypterids (sea scorpions) are a group of extinct, marine euchelicerates that have an extensive Palaeozoic record. Despite lacking a biomineralised exoskeleton, eurypterids are abundantly preserved within select deposits. These collections make statistical analyses comparing the morphology of different genera possible. However, eurypterid shape has not yet been documented with modern geometric morphometric tools. Here, we summarise the previous statistical assessments of eurypterid morphology and expand this research by presenting landmark and semi-landmark analyses of 115 eurypterid specimens within the suborder Eurypterina. We illustrate that lateral compound eye morphology and position drives specimen placement in morphospace and separates proposed apex predators from more generalist forms. Additionally, evidence for size clusters in Eurypterus that may reflect ontogeny is uncovered. We highlight the use of geometric morphometric analyses in supporting the naming of new taxa and demonstrate that these shape data represent a novel means of understanding inter-generic ontogenetic trajectories and uncovering developmental changes within the diverse euarthropod group.

Morphometric variation of fish scales among some species of rattail fish from New Zealand waters

2018 ◽  
Vol 98 (8) ◽  
pp. 1991-1998
Author(s):  
A. L. Ibáñez ◽  
L. A. Jawad
Keyword(s):  
New Zealand ◽  
Discriminant Analysis ◽  
Morphological Evolution ◽  
Procrustes Analysis ◽  
Fish Scales ◽  
Geometric Morphometric ◽  
Morphometric Variation ◽  
Generalized Procrustes Analysis ◽  
Morphometric Methods ◽  
Components Analysis

New Zealand rattail fish are of great interest both to biologists who study their phylogenetics and in fisheries. In contrast, their morphological evolution is little studied and poorly understood. Geometric morphometric methods based on scale shape were applied in this study to determine differences among species and genera. Scale shapes were described using seven landmarks, the coordinates of which were subjected to a generalized Procrustes analysis, followed by a principal components analysis. A cross-validated discriminant analysis was applied to assess and compare the size-shape (centroid size plus shape variables) efficacy in the species and the discrimination of the genera. Two main phenetic groups were identified: cluster no. 1 with eight species and cluster no. 2 with six species. Coelorhinchus aspercephalus and Mesovagus antipodum were more separated from the other species in the first cluster. The cross-validated canonical discriminant analysis correctly classified 74% at the genus level, with most misclassifications occurring between Coelorhinchus and Coryphaenoides, whereas the best classified genera were Mesovagus and Trachyrincus. The discrimination of correctly classified species ranged from 41.2 to 100%. The highest correct classification rates were recorded for Coryphaenoides armatus, Coelorhinchus innotabilis, Trachyrincus longirostris and Mesovagus antipodum.

scholarly journals Do island populations differ in size and shape compared to mainland counterparts?

2019 ◽  
Vol 101 (2) ◽  
pp. 373-385 ◽  
Author(s):  
Sergio Ticul Álvarez-Castañeda ◽  
Laura A Nájera-Cortazar
Keyword(s):  
Geometric Morphometric ◽  
Island Populations ◽  
Terrestrial Vertebrates ◽  
Skull Shape ◽  
Skull Size ◽  
Morphometric Analyses ◽  
Interpopulation Variation ◽  
Pocket Mouse ◽  
Shape Analyses ◽  
Insular Populations

Abstract Adaptation and evolution of terrestrial vertebrates inhabiting islands have been the topic of many studies, particularly those seeking to identify trends or patterns in body size in mammals, albeit not necessarily in shape, in relation to mainland populations. The spiny pocket mouse, Chaetodipus spinatus, is distributed in the Baja California peninsula and its surrounding islands. Insular populations became isolated ~12,000 due to changes in sea level; these populations’ matrilinear (mitochondrial) DNA shows minor interpopulation variation. We tested the hypothesis that adaptation and evolution in these island populations involve variation in both skull size and skull shape (using geometric morphometrics) relative to mainland populations, rather than only in size as previously assumed. A total of 363 specimens from 15 insular and peninsular populations were used in analysis of the skull length and geometric morphometric analyses. Our findings revealed significant differences related to skull size among population. The skull shape analyses showed two significantly different morphotypes: one for all island specimens and one for all mainland samples. Our analyses support the hypothesis that insular populations may not only vary in size relative to mainland populations, but may also show variations in shape, regardless of differing conditions across islands.

scholarly journals Local domestication or diffusion? Insights into viticulture in Greece from Neolithic to Archaic times, using geometric morphometric analyses of archaeological grape seeds

2021 ◽  
Vol 125 ◽  
pp. 105263 ◽  
Author(s):  
Clémence Pagnoux ◽  
Laurent Bouby ◽  
Soultana Maria Valamoti ◽  
Vincent Bonhomme ◽  
Sarah Ivorra ◽  
...  
Keyword(s):  
Grape Seeds ◽  
Geometric Morphometric ◽  
Morphometric Analyses

scholarly journals Heterochronic Shifts Mediate Ecomorphological Convergence in Skull Shape of Microcephalic Sea Snakes

2019 ◽  
Vol 59 (3) ◽  
pp. 616-624 ◽  
Author(s):  
Emma Sherratt ◽  
Kate L Sanders ◽  
Amy Watson ◽  
Mark N Hutchinson ◽  
Michael S Y Lee ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Shape Variation ◽  
Micro Computed Tomography ◽  
Trophic Specialization ◽  
Evolutionary Patterns ◽  
Dietary Specialization ◽  
Geometric Morphometric ◽  
Sea Snakes ◽  
Morphometric Methods ◽  
Cranial Shape

Abstract Morphological variation among the viviparous sea snakes (Hydrophiinae), a clade of fully aquatic elapid snakes, includes an extreme “microcephalic” ecomorph that has a very small head atop a narrow forebody, while the hind body is much thicker (up to three times the forebody girth). Previous research has demonstrated that this morphology has evolved at least nine times as a consequence of dietary specialization on burrowing eels, and has also examined morphological changes to the vertebral column underlying this body shape. The question addressed in this study is what happens to the skull during this extreme evolutionary change? Here we use X-ray micro-computed tomography and geometric morphometric methods to characterize cranial shape variation in 30 species of sea snakes. We investigate ontogenetic and evolutionary patterns of cranial shape diversity to understand whether cranial shape is predicted by dietary specialization, and examine whether cranial shape of microcephalic species may be a result of heterochronic processes. We show that the diminutive cranial size of microcephalic species has a convergent shape that is correlated with trophic specialization to burrowing prey. Furthermore, their cranial shape is predictable for their size and very similar to that of juvenile individuals of closely related but non-microcephalic sea snakes. Our findings suggest that heterochronic changes (resulting in pedomorphosis) have driven cranial shape convergence in response to dietary specializations in sea snakes.

Larval anatomy of Andean tadpoles of Telmatobius (Anura: Ceratophryidae) from Northwestern Argentina

Zootaxa ◽  
2008 ◽  
Vol 1938 (1) ◽  
pp. 40-60 ◽  
Author(s):  
M. FLORENCIA VERA CANDIOTI
Keyword(s):  
Intraspecific Variation ◽  
Characteristic Pattern ◽  
Species Discrimination ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Northwestern Argentina ◽  
Preliminary Results ◽  
Internal Morphology ◽  
Morphometric Methods ◽  
Interspecific And Intraspecific Variation

In this paper I study the oral, buccopharyngeal, and musculoskeletal configuration in tadpoles of nine Telmatobius species from Northwestern Argentina (T. atacamensis, T. ceiorum, T. laticeps, T. oxycephalus, T. pinguiculus, T. pisanoi, T. cf. schreiteri, T. scrocchii, and T. stephani; N = 30, Gosner stages 31–36). Specimens were prepared according to standard clearing and staining protocols; additionally, I applied landmark and outline-based geometric morphometric methods in order to quantify shape variation in chondrocrania, hyobranchial skeletons, and suprarostral cartilages. Although preliminary, results show a marked morphological uniformity on the analyzed levels, and overlapping interspecific and intraspecific variation, which renders species discrimination difficult. Some distinctive traits for the genus are bicuspidate buccal spurs, peculiar arrangement of buccal roof and floor papillae, tetrapartite suprarostral, adrostral cartilages, a lateral slip of the m. subarcualis rectus II-IV invading branchial septum IV, and a characteristic pattern of muscles inserted on the diaphragm. The conservative larval internal morphology in this genus could be explained by a recent speciation and a development possibly characterized by the postmetamorphic appearance of specific features.En este trabajo estudio la morfología oral, bucofaríngea y musculoesquelética de larvas de nueve especies de Telmatobius del Noroeste argentino (T. atacamensis, T. ceiorum, T. laticeps, T. oxycephalus, T. pinguiculus, T. pisanoi, T. cf. schreiteri, T. scrocchii y T. stephani; N = 30, estadios de Gosner 31–36). Los especímenes se prepararon siguiendo protocolos clásicos de transparentación y coloración diferencial; adicionalmente, apliqué métodos de morfometría geométrica basada en landmarks y contornos para cuantificar la variación de formas en condrocráneos, esqueletos hiobranquiales y cartílagos suprarostrales. Aunque de carácter preliminar, los resultados muestran una notable uniformidad morfológica en los niveles analizados, y una variación intraespecífica que se superpone con la interespecífica, dificultando la distinción entre especies. Algunos rasgos distintivos del género son un par de espolones bucales bífidos, un arreglo particular de las papilas del techo y piso bucales, suprarostral tetrapartito, adrostrales, un haz del m. subarcualis rectus II-IV invadiendo el septo branquial IV, y un patrón aparentemente característico de los músculos insertos en el diafragma. La morfología larval interna conservadora en el género podría explicarse por una especiación reciente y un desarrollo posiblemente caracterizado por la aparición postmetamórfica de los rasgos específicos.

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