An annotated checklist and bibliography of the Diaptomidae (Copepoda, Calanoida) of Italy, Corsica, and the Maltese islands

Abstract

Calanoids of the family Diaptomidae are the most widespread copepods in the lentic inland waters of the Palearctic region. In Italy, studies on the family date back to the end of 19th century. Since then, several papers contributed to increasing the knowledge on their presence, distribution, and ecological preferences. Nevertheless, new records for the area and the discovery of putative new species stress that the current knowledge on these inland water crustaceans is still far from being exhaustive. This paper presents an updated and annotated checklist and bibliography of the Diaptomidae of the Italian peninsula and surrounding islands, including Corsica and the Maltese islands, compiled through a critical review of the existing literature and carrying out further field research. The doubtful records reported in the literature are discussed and clarified. The updated checklist includes 30 diaptomid species and subspecies; among them, an alien species and three putative new species pending formal description are reported. About 20% of the observed species are endemic or subendemic to the study area. The faunal provinces ascribed to the Mediterranean limnofaunistic region host the highest species richness and contribute to the checklist with rare species and unique occurrences. The high species richness observed in the Mediterranean area supports the hypothesis of a long-lasting persistence of an ancient and peculiar copepod fauna.

Cryptic diversity, niche displacement and our poor understanding of taxonomy and ecology of aquatic microorganisms

“…A species occurring at high altitudes in southern areas is thus expected to occur at lower altitudes in northern areas, as routinely observed for other diaptomid species (e.g. Hemidiaptomus gurneyi (Roy, 1927), which is strictly linked to mountainous area in Sicily but a typical lowland species in Peninsular Italy, see Alfonso et al, 2021), whereas the opposite pattern is clearly observed in D. cyaneus. Second, the occurrence of D. cyaneus in permanent, sometimes even fish-inhabited, water bodies has never been observed in the southernmost regions of the study area (i.e.…”

“…Second, the occurrence of D. cyaneus in permanent, sometimes even fish-inhabited, water bodies has never been observed in the southernmost regions of the study area (i.e. Tunisia, Sicily, Apulia and Sardinia), whereas the only populations occurring in northern Italy and Corsica are occurring in such a habitat (Alfonso et al, 2021).…”

“…Kiefer, 1978;Błędzki & Rybak, 2016); to date only D. c. admotus Kiefer, 1974 is considered valid and occurring in Dalmatia and Morocco (Kiefer, 1978), whereas the other subspecies are considered junior synonyms of D. cyaneus s.s. In Tunisia, Italy and Corsica, only D. cyaneus s.s. is unanimously reported to occur (Kiefer, 1978;Alfonso et al, 2021). The species is rather common in low to medium altitude temporary ponds in Tunisia, Sardinia, Sicily and Apulia, co-existing sympatrically and sometimes even syntopically and synchronically with the congener D. serbicus Gjorgjweic, 1907 (e.g.…”

“…in Sicily, see Marrone et al, 2006b). Oddly, the occurrence sites of the species in Corsica and central and northern Italy are limited to high-altitude, sometimes permanent water bodies, being replaced by D. serbicus at lower altitudes along the Tyrrhenian coast of the peninsula (Alfonso et al, 2021). In the light of the importance of hydroperiod and climate in determining diaptomid distribution (e.g.…”

The Inland Water Copepod Fauna of a Traditional Rural Landscape in a Mediterranean Island (Crustacea, Copepoda)

“…Identification of collected copepods was performed based on Dussart [48,49], Kiefer [50], Einsle [51,52], Karaytug [53], Hoły ńska et al [54], Hoły ńska [55], Alekseev and Defaye [56], and Miracle et al [57]. Copepod nomenclature here follows Ruffo and Stoch [58], with the exceptions of the genera Arctodiaptomus Kiefer, 1932, and Acanthocyclops Kiefer, 1927, for which we follow Alfonso et al [59] and Miracle et al [57], respectively. Notwithstanding the doubts raised by some authors (e.g., [60,61]), we here consider D. bicuspidatus (Claus, 1857) and D. lubbocki (Brady, 1869) as different taxa of species level.…”