Despite the biological and economic importance of earthworms, the taxonomic status and evolutionary relationships of most lumbricid genera are still under debate. Further complications arise from the recognition that earthworms also show a high cryptic diversity. Past and current field studies of Iranian earthworm fauna have resulted in the identification of a total number of 28 earthworm species. However, many specimens do not fully fit into their original descriptions, making the species assignation very difficult. In this study, we evaluated the genetic diversity using mitochondrial markers as a tool to assess the species occurrence of some problematic species in Iran. Four species with high morphological variation were selected: Aporrectodea caliginosa (Savigny, 1826), Aporrectodea trapezoides (Dugès, 1828), Dendrobaena byblica (Rosa, 1893) and Dendrobaena veneta (Rosa, 1886). Morphological identification was contrasted with the molecular information generated through COI and 16S barcoding and the COI and 16S sequences stored in the Genbank. The results of this first integrative taxonomic analysis revealed that D. veneta consisted of two separated clades and that a number of species assigned to D. byblica showed very close relationships with those belonging to the genus Philomontanus. The lack of taxonomic expertise and identification characters providing a clear and unambiguous identification of earthworms highlights the urgent need of new tools to identify species unequivocally. Therefore, it is concluded that more taxonomical studies are needed to clarify the diagnostic characters and taxonomic status of the species belonging to two genera, Aporrectodea and Dendrobaena (Lumbricidae), in Iran.
Abstract:In the present study two new species of Tetragonocephalum Shipley et Hornell, 1905, T. mackenziei sp. n. and T. kazemii sp. n., are described from the spiral intestine of the cowtail stingray, Pastinachus sephen (Forsskål), from the northern coast of the Gulf of Oman. Tetragonocephalum mackenziei is distinguished from the 16 other valid species of Tetragonocephalum by a unique combination of characteristics, i.e. sperm-filled seminal receptacle in immature proglottids, body length (7.7−17.5 mm), body width (213−288 µm), number of proglottids (34−49), number of testes (10−14), size of scolex (228−315 µm × 213−288 µm) and size of acetabula (56−73 µm × 61−75 µm). Tetragonocephalum kazemii is morphologically distinguishable from its valid congeners and T. mackenziei based on a combination of characteristics, including body length (28.8−36.6 mm), number of proglottids (50−65), number of testes (30−42), size of scolex (388−564 µm × 326−448 µm), size of acetabula (62−86 µm × 57−90 µm) and testes (25−39 × 21−32). This brings the total number of validly described species of Tetragonocephalum to 18 and expands our knowledge of this diverse genus to now include the Gulf of Oman, as well as Arafura Sea, northern Indian Ocean and western Pacific Ocean.
Earthworms are the most important soil invertebrates worldwide, in terms of biomass and effects on soil processes. In this study, 21 earthworm species, including four new records were identified from Caspian Hyrcanian Forests (North of Iran). Four species; Criodrilus lacuum, Lumbricus rubellus, Metaphire californica, and Octodrilus transpadanus and the family Criodrilidae are reported for the first time. Previous studies have identified 31 earthworm species belonging to 14 genera and three families (Lumbricidae, Acanthodrilidae, and Megascolecidae) in Iran; therefore, these new records increase the number of earthworm species to a total of 35.
This research investigates and traces heavy metals (As, Pb, Cd and Cu) in a model of the aqueous food chain in the Aras River, located in northwestern of Iran. The selected model includes the zander (Sander lucioperca L.) and crustacean species known as amphipods (Gammarus spp.) that belong to the food chain of this sh. A total of 172 samples (70 sh and 102 Amphipoda) were collected randomly from the stations and analyzed for heavy metals using an Atomic Absorption Spectrophotometry (AAS). The results showed that the accumulation of heavy metals in both Taxon are in the order of As > Pb > Cd > Cu and concentrations of heavy metals in sh body are higher than Gammarus spp. in every stations in different seasons. Specimens of station (1) due to industrial activities indicates the highest heavy metal content. The concentrations of As, Pb, and Cd exceedes the permissible limits. There is a close correlation between the concentration of heavy metals in the amphipod and zander. The target hazard quotient (THQ), Total target hazard quotient (TTHQ) and Carcinogenic Risk (CR) were calculated to assess human health risk. The average of THQ for As (1.43) exceedes the international standards and will endangere the consumers of this sh species. The TTHQ for heavy metals has been estimated highr than 1. and at all stations, the value of CR Cd > 1×10 − 3 , which reveals the degree of evidence of carcinogenicity of this metal in all parts of the Aras River. Therefore, according to results, effective controls and regular monitoring should be established in this regions
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