Traditional Morphometric Data Research Articles

Elucidating species diversity of genus Betta from Aceh waters Indonesia using morphometric and genetic data

Species of the genus Betta are very similar morphologically which could lead to inaccuracy in taxonomic identification. Therefore, morphological data should also be complemented with other approaches such as genetics to validate the taxonomic status of member species. The objective of this study was to validate the taxonomic status of the genus Betta from Aceh waters using morphometric and genetic data. Sampling was conducted from January to September 2020 at 12 locations within Aceh province. Based on initial assessment identification of morphology, there were four presumed species of Betta in Aceh waters, namely; Betta rubra, Betta dennisyongi, Betta splendens, Betta imbellis. A total of 50 samples from each presumed species were assessed for traditional and truss morphometric analysis, while 5 specimens were randomly selected from each morphospecies for genetic analysis based on the cytochrome oxidase subunit I (COI) gene. The traditional morphometric data divided the four Betta species into two group with B. rubra and B. dennisyongi in same group (group I), while B. splendens and B. imbellis in different group (group II). While, the truss morphometric data divided the four Betta species into three groups with B. rubra and B. dennisyongi in group 1, B. splendens in group 2, while B. imbellis form the other group. The head depth of the fishes was an important characteristic to distinguish members of the four species. In parallel, the genetic analysis supported the occurrence of four valid species with intraspecific values of 0.0–1.59% and interspecific values ranging from 3.3 to 24.7%, the same clustering relationship as in the morphometric data. While B. rubra, B. splendens, and B. imbellis sequences are already available in GenBank, this study reports the first record of B. dennisyongi COI sequences.

Morphological Analysis of Size and Shape (MASS): An integrative software program for morphometric analyses of leaves.

PremiseMorphometric analysis is a common approach for comparing and categorizing botanical samples; however, completing a suite of analyses using existing tools may require a multi‐stage, multi‐program process. To facilitate streamlined analysis within a single program, Morphological Analysis of Size and Shape (MASS) for leaves was developed. Its utility is demonstrated using exemplar leaf samples from Acer saccharum, Malus domestica, and Lithospermum.MethodsExemplar samples were obtained from across a single tree (Acer saccharum), three trees in the same species (Malus domestica), and online, digitized herbarium specimens (Lithospermum). MASS was used to complete simple geometric measurements of samples, such as length and area, as well as geometric morphological analyses including elliptical Fourier and Procrustes analyses. Principal component analysis (PCA) of data was also completed within the same program.Results MASS is capable of making desired measurements and analyzing traditional morphometric data as well as landmark and outline data.DiscussionUsing MASS, differences were observed among leaves of the three studied taxa, but only in Malus domestica were differences statistically significant or correlated with other morphological features. In the future, MASS could be applied for analysis of other two‐dimensional organs and structures. MASS is available for download at https://github.com/gillianlynnryan/MASS.

Discrete and morphometric traits reveal contrasting patterns and processes in the macroevolutionary history of a clade of scorpions.

Many palaeontological studies have investigated the evolution of entire body plans, generally relying on discrete character-taxon matrices. In contrast, macroevolutionary studies performed by neontologists have mostly focused on morphometric traits. Although these data types are very different, some studies have suggested that they capture common patterns. Nonetheless, the tests employed to support this claim have not explicitly incorporated a phylogenetic framework and may therefore be susceptible to confounding effects due to the presence of common phylogenetic structure. We address this question using the scorpion genus Brachistosternus Pocock 1893 as case study. We make use of a time-calibrated multilocus molecular phylogeny, and compile discrete and traditional morphometric data sets, both capturing the overall morphology of the organisms. We find that morphospaces derived from these matrices are significantly different, and that the degree of discordance cannot be replicated by simulations of random character evolution. Moreover, we find strong support for contrasting modes of evolution, with discrete characters being congruent with an 'early burst' scenario whereas morphometric traits suggest species-specific adaptations to have driven morphological evolution. The inferred macroevolutionary dynamics are therefore contingent on the choice of character type. Finally, we confirm that metrics of correlation fail to detect these profound differences given common phylogenetic structure in both data sets, and that methods incorporating a phylogenetic framework and accounting for expected covariance should be favoured.

Where to Live? How Morphology and Evolutionary History Predict Microhabitat Choice by Tropical Tadpoles

AbstractTadpoles have diverse morphologies and occupy diverse habitats. The morphological differences between tadpoles can be represented by linear and geometric measurements and used to explain the organization of tadpole assemblages. However, the effects of evolutionary history must be isolated from the morphological differences before we can determine which patterns result from the use and sharing of common ecological resources. Here, we aimed to determine how morphological similarities and phylogenetic distances affect microhabitat choice by tadpoles. We analyzed the tadpoles of 101 anuran species and classified them according to ecomorphological guild, habitat use, position in the water column, and floor substrate. We used geometric and traditional morphometric approaches to describe the morphological variation among tadpoles and calculated the patristic distance for each species. Afterwards, we used morphometric and phylogenetic matrices as predictors of the variance in the ecological matrix, using a partial redundancy analysis. When we used traditional morphometric data, phylogeny explained a large amount of the ecological variation. By contrast, when we used geometric morphometric data, morphology and phylogeny explained similar amounts of the ecological variation, showing that the technique used to extract morphological variation affects the results. We provide evidence that both morphology, as a surrogate for contemporary factors, and evolutionary inertia are important in determining the behavior of tadpoles. Thus, niche conservatism can be important in modeling the behavior of tadpoles, but does not explain all the preferences of tadpoles.

Morphometric Studies on the Skull in Three Marsupial Species (Koala, Wombat, Wallaby)

Although many gross anatomical studies are published on Phascolarctos cinereus (Koala), Vombatus ursinus (Wombat) and Macropus greyi (wallaby) there appear to be no morphometric studies on the skull of these species. Traditional morphometric data are useful when either absolute or relative sizes are of particular interest, such as in studies of growth. These data are also useful when size measurements are of theoretical importance in studies of functional morphology. Three koala, two wombat and threeGrey’s wallaby skulls were used inthis traditional morphometric study. All estimated morphometric data were expressed as means±SD with the maximum and minimum values. The skull weight (with mandible) was 44.4±8.1 g, 224.5±50.2 g, 55.7±23.1 g & the skull length was 12.0±0.9 cm, 16.6±0.8 cm, 13.2±1.4 cm & the cranial length was 8.7±1.1 cm, 10.4± 0.5 cm, 7.7±0.4 cm. The skull index was 58.333, 77.71, 56.06, cranial index 60.92, 50.96, 54.55, facial index 186.11, 148.44, 114.29 and orbital index 90.00, 85.294, 91.304, and cranial capacity 20.0±2.4 cc, 61.7±11.8 cc, 33.5 ±3.7 cc in the koala, wombat and wallaby respectively. These results were discussed in terms of the usage of these morphometric measurements in several basic and clinical applications as well as in evaluating the intelligence status of these species. Two tables and four figures supported the results of this study.

Geometric craniometric analysis of sexual dimorphism and ontogenetic variation: A case study based on two geographically disparate species, Aethomys ineptus from southern Africa and Arvicanthis niloticus from Sudan (Rodentia: Muridae)

Non-geographic morphometric variation, particularly at the level of sexual dimorphism and ontogenetic (age-related) variation, has been documented in rodents, and useful for establishing whether to analyse sexes separately or together, and for selecting adult specimens for subsequent data recording and analysis. However, such studies have largely been based on traditional morphometric analyses of linear measurements that mainly focus on overall size, rather than shape-related morphometric variation. Unit-free, landmark/outline-based geometric morphometric analyses are considered to offer a more appropriate tool for assessing shape-related morphometric variation. In this study, we used geometric cranial morphometric analysis to assess the nature and extent of sexual dimorphism and age variation within the Tete veld rat, Aethomys ineptus (Thomas and Wroughton, 1908) from southern Africa and the African Nile rat, Arvicanthis niloticus (Desmarest, 1822) from Sudan. The results obtained were in turn compared with previously published results based on independent geometric and traditional cranial morphometric data from the same sampled populations examined in the present study. While our geometric morphometric results detected statistically significant sexual dimorphism in cranial shape within Ar. niloticus only, previously published results based on traditional morphometric data failed to detect significant sexual dimorphism within this species. However, similar to previously published traditional morphometric data, our geometric morphometric results detected statistically significant age-related variation in cranial shape and size within both Ae. ineptus and Ar. niloticus, with individuals of age classes 5 and 6 being considered to represent adult specimens. Our results highlight the importance of carefully evaluating both size- and shape-related non-geographic morphometric variation prior to the analysis of geographic variation and the delineation of species. Erroneous conclusions of non-geographic variation may have implications in the interpretation of geographic and evolutionary processes that may be responsible for morphological differences at both the inter- and intra-specific levels.

Morphometric Variation inHylomyscus AlleniandH. stella(Rodentia: Muridae), and Description of a New Species

We compared 7 populations of woodmice, Hylomyscus stella (Thomas, 1911), from west-central, east-central, and east Africa using traditional morphometric data of the cranium. Our results are congruent with previous molecular and cytogenetic data, and demonstrate that specimens previously identified as H. stella represent 2 cryptic species: H. stella from east-central and east Africa, and Hylomyscus sp. nov. from west-central Africa. According to current knowledge, the new species of Hylomuscus is a forest-dwelling species inhabiting the region between the Sanaga River and the Oubangui and Congo rivers in Cameroon, Central African Republic, Gabon, and Republic of the Congo. It is sympatric, and even syntopic, with the morphologically closely related species H. alleni. These 2 cryptic species can be distinguished by traditional morphometric analysis of the cranium and by examination of molecular data.

Geometric morphometrics and cladistics: testing evolutionary relationships in mega- and microbats

Traditionally, morphometric data have consisted of distances, angles, or ratios, and have been considered inappropriate for cladistic analyses. Recently, geometric morphometrics, based on homologous landmark point-coordinates, has provided a number of advantages over traditional morphometric data and methods, including the possibility that phylogenetically informative characters and character-states may be extracted and used in cladistic analyses. Using two data sets of 3-dimensional point coordinates collected from skulls of bats, we empirically evaluate this possibility. Partial warps were extracted from the point-coordinate matrix, and these were then re-coded by gap-coding, for use in the cladistic analyses. In the case of samples from Eidolon helvum populations (two mainland localities and four islands in the Gulf of Guinea), analyzing males and females separately, our analyses based on these data were unable to detect consistent phylogeographic patterns among the populations. In the case of samples from plecotine bat species, these analyses produced a consensus cladogram showing considerable concordance with an earlier cladistic analysis by us of this group. In both cases, our results reflect those of earlier studies (based on both morphologic and genetic data), suggesting that the data and analytic techniques described herein may have interesting utility in cladistic analyses.