Groundwater copepods: diversity patterns over ecological and evolutionary scales

Copepods are common components of the groundwater fauna, and greatly increase the diversity of groundwater communities. With more than 900 species/subspecies known from continental groundwaters, stygobiont copepods inhabit all kinds of aquifers (karstic, fissured, porous), as well as surface/subsurface ecotones (land/water and water/water). The polyhedral and varied structure of the stygohabitats is reflected in the surprising mixture of functional morphologies and habitat exploitations experienced by groundwater copepods. Morphological adaptations and specializations are discussed, as well as the chronology of their appearance in the evolutionary history of several taxa. Diversity patterns of copepod assemblages in groundwater are examined under both structural and functional profiles, as well as across a range of scales. Structure and function operate in an interactive, sometimes hierarchical ways, as well as scales. On the ecological scale, local heterogeneity and patchiness in geomorphic and hydrologic characteristics, as well as biotic interactions, are to be considered causal factors affecting the diversity patterns over a range of spatial and temporal scales. On the evolutionary scale, it is widely accepted that stygobiont copepods evolved from ancestors living in marine, freshwater and semiterrestrial environments. They gained access to the groundwater through major highways represented by the interstitial and the crevicular/karstic corridors. `Phylogenetic diversity' in groundwater copepod taxocoenoses is viewed as a heterogeneous assemblage of species belonging to different phylogenetic lineages, which entered groundwater at different times and by different ways.     

Towards a revision of the genus Parastenocaris Kessler, 1913: establishment of Simplicaris gen. nov. from groundwaters in central Italy and review of the P. brevipes-group (Copepoda, Harpacticoida, Parastenocarididae)

A new genus Simplicaris (Copepoda, Harpacticoida, Parastenocarididae) is established to accommodate two species collected from deep groundwater in Italy, S. lethaea sp. nov. and S. veneris (Cottarelli & Maiolini, 1980) comb. nov. Parastenocaris hippuris Hertzog, 1938 and P. aedes Hertzog, 1938 are ranked as incertae sedis within the genus. Members display complete absence of leg 5 in both sexes and an unusual elongation of the first exopodal segments of legs 1–4, in which exp-1 is distinctly longer than exp-2 or -3, or as long as exp-2 and -3 combined. As the systematic status of the family Parastenocarididae and of the type genus Parastenocaris is still in flux, a list of phylogenetically informative characters is proposed, along with a discussion of their various states in representative members of the family. The genus Parastenocaris sensu stricto is redefined to comprise only the brevipes -group. The remaining members of the genus are considered Parastenocaris sensu lato pending a thorough revision of the family.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 417−436.     

Morphological and trophic specialization in a subterranean amphipod assemblage

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Phylogenetic relationships in Kerkia and introgression between Hauffenia and Kerkia (Caenogastropoda: Hydrobiidae)

Freshwater truncatelloidean gastropods include numerous minute cryptic species, displaying simple morphologies, all of which hampers their taxonomic research based on morphology. Phylogenetic relationships among all but one extant species of the genus Kerkia from five localities in Croatia and one in Slovenia were therefore analysed based on one mitochondrial (cytochrome c oxidase subunit I) and three nuclear markers (18S, 28S and H3). Kerkia kusceri (Bole, 1961 ), K. jadertina Ku??er, 1933, K. j. sinjana (Ku??er, 1933), and K. kareli Beran, Bodon et Cianfanelli, 2014, were collected from their type localities. Our analysis confirmed their distinctness, recovering two additional clades that may represent yet undescribed species from Croatia. Apart from Kerkia, Hauffenia media Bole, 1961 , H. subpiscinalis (Ku??er, 1932) and H. erythropomatia (Hauffen, 1856) from Slovenia were analysed. Their distinctness together with the rejection of the eligibility for separate genus Erythropomatiana for the latter species was proven. Interestingly, its sequence divergence exceeded all previous estimates for species‐level divergence within the Truncatelloidea, implying a species‐level separation both for the COI and for nuclear loci. High p‐distances for the COI/nuclear loci (0.128/0.027, respectively) confirmed also the uniqueness of both genera. A comparison of their COI sequences with the reference sequences of Alzoniella Giusti et Bodon, 1984, Avenionia Nicolas, 1882, Fissuria Boeters, 1981, and Agrafia Szarowska et Falniowski, 2011, has shown that Kerkia and Hauffenia are not sister clades. The most striking, however, was the apparent introgression of the ‘Hauffenia’ mtDNA type from central Slovenia (cave Babja luknja) into two Kerkia clades from central (Ljuba?) and southern (Podgra?e) Croatia, that are located 210 km and 360 km away, respectively. The introduced ‘Hauffenia’ mtDNA type and the closest Hauffenia erythropomatia COI differed by 0.8%. Secondary loss of isolating mechanisms between phylogenetically distant organisms and the severe lack of information on distribution of these underground taxa were postulated as possible explanations of this interesting phenomenon.     

Oligochaetes in southern European groundwater: new records and an overview

This work deals with an overview of the faunal composition and presents a general ecological approach to the groundwater oligochaetes in southern Europe. The species richness is high and similar to that of the superficial waters in the same area. Among the 150 species that we found, about 29 are stygobiont, so the total number of stygobiont species in the area studied has been increased to 58. Ten of these species are tubificids with marine phyletic affinities. A list of the most frequently found species and the relative abundance of the different families and genera collected in the main environments investigated are presented. Although enchytraeids often dominated the fauna, lumbriculids and tubificids exhibit a high level of diversity and comprised the majority of stygobiont and stygophilous taxa found. The discovery of members of the family Parvidrilidae in southern European caves is the first outside of North America. This indicates that the family is widely distributed in the Palearctic region and typical of underground waters. Here, we update the previous evaluation of the knowledge about oligochaetes inhabiting groundwater: 96 species of stygobiont freshwater oligochaetes (sensu stricto) are now known in the world and 81 of them have been recorded from the Palearctic region.     

Rapid breakdown of allochthonous and autochthonous plant material in a eutrophic river

A few specimens of Pseudectinosoma reductum sp.n. were collected from a crenal biotope of the Presciano spring system(Tirino River, Aterno-Pescara Basin) in central Italy, at an altitude of 330 m a.s.l. This remarkable new species is easily distinguishable from all congeners in the unique shape of the fifth leg, which lacks any trace of armature. This character state as well as the reduced armature of legs 1–4 and the 4-segmented antennule may be considered evolutionary novelties within the genus. Ecological information is given for the species. This revised version was published online in August 2006 with corrections to the Cover Date.     

A new genus of cave‐dwelling microcrustaceans from the Dinaric Region (south‐east Europe): adaptations of true stygobitic Cladocera (Crustacea: Branchiopoda)

We revise ‘true’ stygobitic cladocerans and lift three species from Alona Baird, 1843 (Cladocera: Chydoridae). Species of Brancelia gen. nov. are inhabitants of saturated karst, collected in pools of residual water in the amphibious zones of a few caves in the Dinaric Region, Europe. All species are blind (regression of eye and ocellus), have elongated sensorial equipment (aesthetascs) and a short rostrum, reduced antennal spines, and a globular body. In contrast to earlier hypotheses, there is no epigean chydorid taxon from the Palaearctic that can be linked to Brancelia gen. nov. The new genus may be an offshoot of six‐limbed Aloninae, but a littoral‐benthic ancestor is not apparent and most likely extinct. Evolution of Brancelia gen. nov. parallels that of other subterranean Cladocera like Phreatalona Van Damme, Brancelj & Dumont, 2009. We discuss the functional morphology of Brancelia gen. nov. and compare its adaptations to a subterranean life mode with those of Phreatalona. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 31–52.