Morphological Redescription and Monthly Variation in the Population Density of the Terrestrial Isopod Porcellionides pruinosus (Isopoda: Porcellionidae) in Southern Iraq

Abstract

This study provides an integrative ecological and taxonomic assessment of Porcellionides pruinosus (Brandt, 1833) from agricultural habitats in Dhi Qar Province, southern Iraq. Field sampling was conducted monthly from August 2024 to July 2025 across four agricultural stations: Al-Shatrah, Al-Rifai, Al-Nasr, and Qalat Sukkar. Morphological redescription confirmed key diagnostic traits including a subrectangular cephalon, pale reticulate patterning, and spear-shaped uropods consistent with previously published descriptions of the species. Population density exhibited clear spatial and seasonal fluctuations. The annual mean density was highest in Al-Rifai (281.3 ± 108.2 ind./m²) and Al-Nasr (257.1 ± 123.5 ind./m²) followed by Al-Shatrah (246.3 ± 91.2 ind./m²) and Qalat Sukkar (213.7 ± 92.3 ind./m²). Peak values were recorded during spring, especially in March and April, while the lowest densities occurred in winter months. These patterns reflect the species’ ecological adaptability and seasonal responsiveness under semi-arid conditions. The findings highlight the potential of P. pruinosus to serve as a bioindicator of soil health and habitat stability in disturbed agroecosystems. This study also provides novel regional data to the limited body of knowledge on terrestrial isopods in the Middle East.