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This paper presents the first overview of aquatic alien invertebrate species (AIS) in the three major river basins (Tigris, Euphrates and Shatt Al-Arab) in southern Iraq. The results are based on field studies undertaken in 2021 and 2022. Thirteen AIS have been recorded. Three of them are "old invaders" (first recorded in the early 19th century to 1970), two species are "intermediate invaders" (first recorded between 1970 to 1990) and eight are "new invaders" (first recorded after 2000). The number of AIS has been growing substantially since 2000. The highest AIS number is recorded in the Shatt-Al-Arab (11 species), a middle number in the Euphrates basin (10 species) and the lowest number in the Tigris (6 species). On the whole, 31% of the recorded species originate from Southern America or Northern America, 23% from Asia, 8% from Southern Europe, Africa and Southern Asia, the Atlantic Ocean, Africa and Northern America, 7% from New Zealand, and the Caspian Sea. Most AIS were likely introduced unintentionally. The study demonstrated that many AIS, like e.g. Macrobrachium nipponense, have been collected both from the upper and the lower sections of the study rivers providing successful examples of aquatic AIS that can establish populations in fresh and brackish waters. The compiled species list is a first step toward the management of the invasive species that are now present in rivers of southern Iraq. It provides a basis for the creation of monitoring programs, early detection initiatives, and quick responses to prevent future invasions in the Tigris-Euphrates and Shatt Al-Arab basins. [ABSTRACT FROM AUTHOR]

The studies on the bioinvasion phenomenon focus mainly on the biological and ecological traits of a species, while scattered literature is addressed to a correct systematic assessment and an updated geographical distribution on the whole. It is noteworthy that non-indigenous species should be monitored on both sides of their range, i.e., towards the front of dispersal and beyond the original range. The backside range boundaries are not often monitored or well delimited; thus, the novel global distribution of an invasive taxon is not often accurately delimitated. A model species for highlighting criticisms about the scarce knowledge on the novel range was chosen. Brachidontes pharaonis is a mussel that has successfully colonised the Mediterranean Sea, following an immigration pathway through the Suez Canal from the Red Sea, presumably from a wider Indo-Pacific area. In this case, the Indo-Pacific boundaries have been overlooked and are still misunderstood due to diverse causes, principally as the synonymy with the congeneric B. variabilis has created confusion in the taxonomic identification. The present review demonstrates that the borders of the B. pharaonis range are still unclear and that the species should be analysed in a wider geographical area. Records of B. pharaonis from Southeast Asia should be treated with caution as this area is out of its range. The Indian and Pacific Oceans host the taxon B. variabilis, composed of two potential cryptic species. Data from the literature highlight the importance of the integrative taxonomic approach to solving various issues concerning the species group complex, morphological variations and cosmopolitan claims of species. [ABSTRACT FROM AUTHOR]

Abstract Background Little attention has been paid to the consequences of the last landbridge between Africa and Sicily on Mediterranean biogeography. Previous paleontological and scarce molecular data suggest possible faunal exchange later than the well-documented landbridge in the Messinian (5.3 My); however, a possible African origin of recent terrestrial Sicilian fauna has not been thoroughly tested with molecular methods. To gain insight into the phylogeography of the region, we examine two mitochondrial and two nuclear markers (one is a newly adapted intron marker) in green toads (Bufo viridis subgroup) across that sea barrier, the Strait of Sicily. Results Extensive sampling throughout the western Mediterranean and North Africa revealed a deep sister relationship between Sicilian (Bufo siculus n.sp.) and African green toads (B. boulengeri) on the mitochondrial and nuclear level. Divergence times estimated under a Bayesian-coalescence framework (mtDNA control region and 16S rRNA) range from the Middle Pliocene (3.6 My) to Pleistocene (0.16 My) with an average (1.83 to 2.0 My) around the Pliocene/Pleistocene boundary, suggesting possible land connections younger than the Messinian (5.3 My). We describe green toads from Sicily and some surrounding islands as a new endemic species (Bufo siculus). Bufo balearicus occurs on some western Mediterranean islands (Corsica, Sardinia, Mallorca, and Menorca) and the Apennine Peninsula, and is well differentiated on the mitochondrial and nuclear level from B. siculus as well as from B. viridis (Laurenti), whose haplotype group reaches northeastern Italy, north of the Po River. Detection of Calabrian B. balearicus haplotypes in northeastern Sicily suggests recent invasion. Our data agree with paleogeographic and fossil data, which suggest long Plio-Pleistocene isolation of Sicily and episodic Pleistocene faunal exchange across the Strait of Messina. It remains unknown whether both species (B. balearicus, B. siculus) occur in sympatry in northern Sicily. Conclusion Our findings on green toads give the first combined mitochondrial and nuclear sequence evidence for a phylogeographic connection across the Strait of Sicily in terrestrial vertebrates. These relationships may have implications for comparative phylogeographic research on other terrestrial animals co-occurring in North Africa and Sicily.