Qualitative and quantitative analyses of the Carboniferous ostracod genus Carbonita from Rod El-Hamal area, Wadi Araba, north Eastern Desert, Egypt

The present work provides a qualitative analysis of the studied ostracod carapaces of the genus Carbonita. Thirty-seven ostracod specimens were collected from the Late Carboniferous Rod El-Hamal Formation at Rod El-Hamal area, Wadi Araba, north Eastern Desert, Egypt. The collected ostracods were assigned to four species in genus Carbonita; C. fabulina (Jones and Kirkby), C. inflata (Jones and Kirkby), C. humilis (Jones and Kirkby), and C. bairdoides (Jones and Kirkby) according to the qualitative traits. In order to assess the discrimination among the different Carbonita species, a new technique, geometric morphometric analyses, was carried out using ImageJ and MorphoJ software packages. Geometric morphometric analyses included landmark configurations, procrustes superimposition, principle component analysis, and thin plate spline deformation plots. Using nine landmarks, average shapes of the different Carbonita species have been provided. The principle component analysis separated Carbonita fabulina and C. bairdoides from the morphologically overlapped C. inflata and C. humilis. Shape variations in the carapace length, height, anteroventral arc, posterodorsal arc, posteroventral arc, and the anterior margin were demonstrated through the deformation plots. These quantitative analyses, along with the qualitative examination, provided considerable variations among the different Carbonita species, and hence the best way for species discrimination.