Copepods

The copepods are the largest and most diversified group of crustaceans. At present they include over 14.000 species, 2.280 genera and 210 families, a surely underestimated number, inhabiting sea and continental waters, semiterrestrial habitats, or living in symbiotic relationships with other organisms. They are considered the most plentful multicellular group on the earth, outnumbering even the insects, which include more species, but fewer individuals! Particularly, the copepods are the dominant forms of the marine plankton and constitute the secondary producers in the marine environments and a fundamental step in the trophodinamics of the oceans.

During their long evolutionary history, starting in the Lower Cretaceous, copepods spread over all the continents, as well as they successfully colonized about all the available water habitats of the Planet, becoming well adapted or specialized to very different salinity regimes, from marine and hypersaline waters to continental freshwater bodies, and to a wide range of temperature from the polar to the hot springs waters.

Copepods regularly live also in marine and freshwater sediments, in different groundwater substrates, in continental and anchialine caves (limestone caves), cenotes, ephemeral water bodies, marshes, wet campos, deep-sea hydrothermal vents and on plants as well. Moreover free-living cyclopoid and harpacticoid copepods may form an important component of cryptozoic fauna in moist forest litter (Reid, 1986; Fiers & Ghenne, 2000). Coastal, estuarine brackish waters harbor many copepod genera and species which can persist in these unfavourable habitats mainly as resting, diapausing eggs. Copepods can be found also in strange cryptic habitats, such as the small pools between the leaves of some tropical plants, crab burrows, tree holes and even discarded car tyres (!). Copepods, as many other aquatic organisms, can be easily transported, either actively or passively, often as resistant stages (Sars, 1901; Van de Velde 1984; Matsumura-Tundisi et al. 1990; Saunders et al., 1993; Reid & Reed 1994).

Neverthless, the astonishing success of this group of microcrustaceans is due to their symbiotic relationships with other organisms: in fact, they virtually can parasitize or be the intermediate hosts of all the animal groups, from sponges to vertebrates, including mammalians and man, and it is likely that the number of associated or parasitic taxa known today could represent only a small fraction of the living species, especially in marine waters. Copepods that parasitize fish skin and gills are serious pests of commercial importance in both marine and freshwater fish farms.

Stygobitic copepods originated from surface, marine and freshwater ancestors, and they reached different groundwater habitats mostly through interstitial and crevicular or karstic corridors. Typical groundwater harpacticoid and cyclopoid copepods (Graeteriella, Maraenobiotus, Moraria) seem to occupy large distribution areas, as a consequence of their greater dispersion capabilities as compared to those of macrofaunal subterranean elements (Fiers & Ghenne, 2000).

The systematics of copepods has been subjected to numerous revisions during the last decade and before: at present, according to Huys R.& G.A. Boxshall (1991), ten orders are recognized, half of which (Misophrioida, Monstrilloida, Mormonilloida, Siphonostomatoida, Poecilostomatoida) mostly contains exclusive symbiotic or parasitic species, the others (Platycopioida, Calanoida, Harpacticoida, Gelyelloida, Cyclopoida) as a rule include free-living forms.

Brachiura are also included with the Copepoda, since many parasitic copepod researchers also study these parasites of fish, commonly referred to as sea lice.

The Class Brachiura is comprised of 1 Family and 4 Genera: Argulus, Chonopeltis, Dipteropeltis, Dolops.

Calanoids, cyclopoids and harpacticoids show a remarkable ecological interest, since most species of these orders generally form the first link of the aquatic food chains, from the microscopic phytoplanktonic algae up to the fishes and mammalians. Recent researches, including those carried out by the Dipartimento di Scienze Ambientali of the University of L'Aquila (Italy), are pointing out an analogous importance for cyclopoid and harpacticoid species inhabiting both surface and underground fresh waters, and particularly the sediments between the superficial hyporheic zone and the rivers bottom, an interesting transitional system or ecotone between epigean and stygal waters.

As a matter of fact, the contiguity with surface waters and the regular occurence of epigean elements in the hyporheic habitats let now the hydrobiologists to consider that a good estimation of rivers meiobenthic conditions must pass through a careful knowledge of the relative groundwater communities. In this last regard, an increasing number of harpacticoid and cyclopoid species are actually revealing their noteworthy importance as "pollution markers" in the environmental control of hyporheic systems and other aquatic habitats, such as lakes, springs, rivers and superficial ground waters.

Although the present knowledge of the copepod fauna of Italy, as a whole, is still largely incomplete, subterranean taxa (including anchihaline waters dwellings) are without doubt much better known than surface ones.

Groundwater copepods of Italy are represented by members of the orders Cyclopoida, Harpacticoida, Calanoida and Misophrioida, most of which are stygobitic or stygophilic inhabitants of underground water systems.

They are widely distributed and most successful in nearly all freshwater underground habitats of the country, viz. springs, wells, interstitial media, coastal waters and pools in caves; fresh or brackish coastal waters may often harbor representatives of generally marine taxa, such as Halicyclops and Neocyclops among the cyclopids, and Ectinosoma, Halectinosoma, Pseudectinosoma, Arenopontia and Delamarella among the harpacticoids.

About half of the over 200 known species appear to be endemic to Italy, the remaining ones are for the most part european and palaearctic or they show a wider or cosmopolitan distribution.

A large amount of specialized taxa is found amongst the cyclopids and harpacticoids; on the contrary, the calanoid order, which is very limited in the subterranean realm, is poorly represented also in the ground waters of Italy where a single species, Troglodiaptomus sketi, recently discovered in karstic substrates of Venetia (North Italy), is known. The order Misophrioida, as well, include a single subterranean species, Expansophria sarda, known for anchialine habitats of Sardinia.

Among the cyclopids, the genus Diacyclops is the most diversified and widespread both in continental and insular part of the country, with more than 30 subterranean species/subspecies which concentrate in the Apennine and Sardinian provinces.

They are for the most part (languidus-languidoides group) stygobitic species, cave dwelling or adapted to interstitial and moss media; the others, belonging to the bicuspidatus-group, could be considered as stygophilic or stygoxen species, since they regularly live, besides ground waters, in a wide range of epigean freshwater bodies, such as lakes, rivers, marsh, as well as brackish coastal waters.

A remarkable endemism occurs in this genus, which includes a conspicuous number of taxa, such as D. bicuspidatus lucanus, D. crassicaudis var. cosana, D. crassicaudis lagrecai, D. crassicaudis trinacriae, D. cristinae, D. ichnusae, D. languidoides aprutinus, D. lindae, D. maggii, D. nuragicus, D. paolae, D. paralanguidoides, D. ruffoi and D. sardous, with a distribution limited to Italy.

The remarkable stygobitic genera Speocyclops and Graeteriella include less species, as well as they show a distribution limited to the Alpine or central Apennine provinces and Sardinia.

The genus Metacyclops contains, as well, noteworthy stygobitic species, such as M. stammeri and M. subdolus, from South Italy, M. gasparoi and M. trisetosus from Northeastern Italy.

The genera Eucyclops and Acanthocyclops, which are considered primarily epigean genera, harbor also some stygobitic or stygophilic species, endemic to Italy. Other genera (Halicyclops, Neocyclops, Macrocyclops, Paracyclops, Tropocyclops, Cyclops, Thermocyclops, Mesocyclops) regularly live in surface waters and only occasionally they can be found in groundwater networks of Italy, as well as they occur throughout most of the country.

The harpacticoid order is represented in Italy by more stygobitic species, for the most part endemic to the country.

The family Parastenocarididae, which at present contains five recognized genera, viz. Parastenocaris, Forficatocaris, Paraforficatocaris, Potamocaris and the recently described Murunducaris, is represented in Italy only by the most speciose and widespread genus Parastenocaris.

Formerly, this genus was supposed to be represented in Italy only by seven species, sampled in caves (Campania), rivers and lakes (North Italy); later on, due to the considerable attention focused on this genus in recent years, the number of species is remarkably increased, and to date 27 taxa, most endemic, are known from Italy.

Interestingly enough, since the interstitial habitat, although spatially continuum, is rather heterogeneous, both in biotic and chemiophysical factors, some italian species of the nominate genus seem to be particularly affected by changes in environmental characteristics, and to be patchy distributed along the groundwater systems.The distribution of four species of Parastenocaris in the lake sandbanks of central Italy (Lazio) is in agreement with the above hypothesis: three species are more or less homogeneously distributed along the shore interstitial, while P. veneris can be found only in deep ground waters.The endemic P. ima (La Maddalena island, Sardinia) lives only in deep phreatic waters; in fact, this very demanding and specialist taxon was never sampled, although repeated investigations, in superficial ground waters.

Other interesting italian stygobitic or stygophilic harpacticoid species belong to the following families: Ameiridae, with the genera Nitocrella, Parapseudoleptomesochra and Psyllocamptus; Canthocamptidae, with the genera Ceuthonectes, Elaphoidella, Neoelaphoidella and Elaphoidellopsis; Laophontidae with the genus Esola; Ectinosomatidae, with the genera Pseudectinosoma and Ectinosoma; Leptopontidae with the genera Ichnusella and Arenopontia.

Of the 18 and 10 italian species referred to Elaphoidella and Nitocrella respectively, more than 50% are endemic to Italy.

Schizopera, a genus belonging to the family Diosaccidae, which includes species generally living in marine or brackish waters, is well represented in Italy also in continental or costal ground waters.

Different colonization pathways could be pointed out for the italian groundwater copepods, and they are mostly related to different geological and palaeogeographical events pending the late Miocene and Quaternary.

Particularly, some genera, such as Halicyclops, Neocyclops, Nitocrella and Parapseudoleptomesochra could be directly sea-originated, through coastal habitats, according to the "Two-step Model Evolution", and owing to the freshening of coastal interstitial waters following sea regressions or tectonic uplift ; other genera probably reached the continental ground waters from the sea, but through karstic environments or via anchialine caves. Other ones, viz. Speocyclops, Graeteriella, Bryocamptus, Elaphoidella, Moraria and Diacyclops, successfully colonized the continental ground waters from surface fresh water bodies, during different geologic ages, as a result of drastic climatic changes.

The Parastenocarididae, including only true interstitial freshwater species, probably evolved from a marine psammic ancestor, phylogeneticalhy related to Cylindropsyllidae.

As regard the thalassoid forms, we hereby mention only the genera Arenopontia and Delamarella, which were supposed to inhabit exclusively marine and brackish interstitial waters.

The recent discovery of Arenopontia species in continental fresh waters can be explained by the active migration model (Coineau & Boutin, 1993), which can also be in agreement with the occurence, in marine genera as Ectinosoma, Halectinosoma, Arenosetella and Delamarella, of continental groundwater species.

Among the sea-originated taxa, some species of the genera Nitocrella, Parapseudoleptomesochra, and Schizopera could have dispersed actively to previously uncolonized areas due to their high degree of salinity tolerance (Active Migration Model).

The origin of the few italian species of the genera Thermocyclops and Ceuthonectes is still doubtful, since they show discontinuous or isolated distribution.

Family Cyclopidae

Genus Acanthocyclops

Acanthocyclops agamus Kiefer 1938 (3) *
Acanthocyclops gordani Petkovski 1971 (1)
Acanthocyclops hispanicus Kiefer 1937 (1)
Acanthocyclops kieferi (Chappuis 1925) (3)
Acanthocyclops orientalis Borutzki 1966 (3)
Acanthocyclops sambugarae Kiefer 1981 (= A. hispanicus ?) (1) *
Acanthocyclops troglophilus Kiefer 1981 (1)
Acanthocyclops venustus italicus Pesce & Maggi 1979 (3) *
Acanthocyclops venustus stammeri (Kiefer 1930) (1)

Genus Diacyclops

Diacyclops antrincola Kiefer 1967 (1,3)
Diacyclops belgicus (Kiefer 1936) (1,3)
Diacyclops bicuspidatus lucanus Pesce & Galassi 1985 (3) *
Diacyclops charon Kiefer 1931 (1)
Diacyclops clandestinus (Kiefer 1926) (1,2,3,4,5)
Diacyclops crassicaudis cosana Stella & Salvadori 1954 (3) *
Diacyclops crassicaudis lagrecai Pesce & Galassi 1987 (5) *
Diacyclops crassicaudis trinacriae Pesce & Galassi 1987 (5) *
Diacyclops cristinae Pesce & Galassi 1987 (3) *
Diacyclops (=Acanthocyclops?) hypogeus Kiefer 1930 [North-east Italy; cave]
Diacyclops ichnusae Pesce & Galassi 1985 (2) *
Diacyclops languidoides languidoides (Lilljeborg 1901) (1)
Diacyclops languidoides aprutinus Pesce Pesce & Fabrizi 1979 (3) *
Diacyclops languidoides italianus (Kiefer 1931) (1)
Diacyclops languidoides nagysalloensis Kiefer 1927 (3)
Diacyclops lindae Pesce 1986 (3) *
Diacyclops maggii Pesce & Galassi 1987 (3) *
Diacyclops nuragicus Pesce & Galassi 1985 (2) *
Diacyclops paolae Pesce & Galassi 1987 (1,2) *
Diacyclops paralanguidoides Pesce & Galassi 1987 (1,3) *
Diacyclops ruffoi Kiefer 1981 (1) *
Diacyclops sardous Pesce & Galassi 1987 (2) *
Diacyclops tantalus (Kiefer 1937) (1)
Diacyclops zschokkei (Graeter 1910) (1,2,3)

Genus Eucyclops

Eucyclops graeteri (Chappuis 1927) (2,3)
Eucyclops macrurus damianae (Petkovski 1971) (3)
Eucyclops macrurus intermedius (Damian 1955) (3)
Eucyclops ibleicus Pesce & Galassi 1987 (5) *
Eucyclops longispinosus Pesce & Galassi 1987 (5) *
Eucyclops subterraneus (Graeter 1908) (2,4)

Genus Graeteriella

Graeteriella unisetigera (Graeter 1908) (1,3)

Genus Halicyclops

Halicyclops dalmatinus Petkovski 1955 (3,5)
Halicyclops rotundipes Kiefer 1935 (3,5)
Halicyclops rotundipes putealis Lindberg 1949 [south Italy; caves, wells]
Halicyclops troglodytes Kiefer 1954 (2,3,5)

Genus Neocyclops
subgenus Protoneocyclops

Neocyclops (Protoneocyclops) mediterraneus (Kiefer, 1960) [south Italy; caves,]

Genus Megacyclops

Megacyclops brachypus Kiefer 1954 (2)

Genus Metacyclops

Metacyclops gasparoi Stoch 1987 (1) *
Metacyclops minutus (Claus 1863) (2,3)
Metacyclops stammeri Kiefer 1938 (2,3,4,5)
Metacyclops subdolus Kiefer 1938 (2,3,4,5)
Metacyclops trisetosus Herbst 1957 (1)

Genus Speocyclops

Speocylops demetiensis (Scourfield 1932) (1)
Speocylops franciscoloi (Brian 1951) (1) *
Speocylops infernus (Kiefer 1930) (1) *
Speocylops italicus Kiefer 1938 (3) *
Speocylops sardous Lindberg 1956 (2) *

Family Cyclopinidae

Genus Muceddina

Muceddina multispinosa Jaume & Boxshall 1996 (2)

Family Misophriidae

Genus Expansophria

Expansophria sarda Jaume & Boxshall 1996 (2) *

Family Diaptomidae

Genus Troglodiaptomus

Troglodiaptomus sketi Petkovski 1978 (1)

Family Diosaccidae

Genus Schizopera

Schizopera cicolanii Galassi & Pesce 1988 (4) *
Schizopera clandestina (Klie 1924) (1)
Schizopera lagrecai Pesce 1987 (5) *
Schizopera lindae Apostolov & Pesce 1987 (3) *
Schizopera subterranea Lang 1948 (3) *

Family Ameiridae

Genus Psyllocamptus

Psyllocamptus monachus (Chappuis 1938) (3) *

Genus Nitocrella

Nitocrella achaiae Pesce 1980 (3,4)
Nitocrella beatricis Cottarelli & Bruno 1994 (2) *
Nitocrella fedelitae Pesce 1985 (3) *
Nitocrella juturna Cottarelli 1975 (3) *
Nitocrella kunzi Galassi & De Laurentiis 1997 (3) *
Nitocrella morettii Pesce 1984 (1,3) *
Nitocrella pescei Galassi & De Laurentiis 1997 (3) *
Nitocrella psammophila Chappuis 1955 (1,3)
Nitocrella stammeri Chappuis 1938 (2,3,4,5)
Nitocrella stochi Pesce & Galassi 1986 (1) *

Genus Parapseudoleptomesochra

Parapseudoleptomesochra italica Pesce & Petkovski 1980 (3) *
Parapseudoleptomesochra minoricae (Chappuis & Rouch 1959) (2)
Parapseudoleptomesochra subterranea (Chappuis 1928) (2)

Family Canthocamptidae

Genus Ceuthonectes

Ceuthonectes serbicus Chappuis 1924 (1)
Ceuthonectes pescei Cottarelli & Saporito 1985 (2) *

Genus Elaphoidella

Elaphoidella aprutina Pesce, Galassi & Apostolov 1987 (3) *
Elaphoidella cottarellii Pesce & De Laurentiis 1993 (1996) (3) *
Elaphoidella cvetkae Petkovski 1983 (1)
Elaphoidella elaphoides (Chappuis 1923) (3, 5)
Elaphoidella italica Pesce, Galassi & Apostolov 1987 (3,5) *
Elaphoidella janas Cottarelli & Bruno 1994 (2) *
Elaphoidella jeanneli (Chappuis 1928) (1)
Elaphoidella mabelae Galassi & Pesce 1991 (3) *
Elaphoidella nuragica Pesce & Galassi 1986 (2) *
Elaphoidella oglasae Cottarelli & Torrisi 1974 (2) *
Elaphoidella paraelaphoides Pesce, Galassi & Apostolov 1987 (3) *
Elaphoidella phreatica (Chappuis 1925) (1,3)
Elaphoidella plutonis plutonis Chappuis 1938 (3) *
Elaphoidella plutonis quadrispinosa Chappuis 1938 (3) *
Elaphoidella rossellae Pesce, Galassi & Apostolov 1987 (3) *
Elaphoidella ruffoi Chappuis 1953 (1) *
Elaphoidella subplutonis Pesce, Galassi & Apostolov 1987 (3) *
Elaphoidella tiberina Pesce & Galassi 1983 (3) *

Genus Elaphoidellopsis

Elaphoidellopsis dubia (Kiefer 1931) (1) *

Genus Neoelaphoidella

Neoelaphoidella apostolovi Pesce & De Laurentiis 1994 (3) *

Genus Moraria

Moraria denticulata Chappuis 1938 (3) *
Moraria michielettoae Brian 1955 (1) *

Genus Attheyella
Subgen. Mrazekiella

Attheyella (Mrazekiella) paranaphtalica Pesce & Galassi 1988 (3,5) *

Genus Bryocamptus
Subgen. Rheocamptus

Bryocamptus (Rheocamptus) dentatus Chappuis 1937 (3)
Bryocamptus (Rheocamptus) unisaetosus Kiefer 1930 (1)
Bryocamptus (Rheocamptus) pygmaeus (Sars 1863) (1)
Bryocamptus (Rheocamptus) zschokkei tatraensis (Minkiewicz 1916) (1)

Subgen. Limocamptus

Bryocamptus (Limocamptus) cfr. dacicus (Chappuis 1923) (1)

Genus Echinocamptus

Echinocamptus georgevitchi (Chappuis 1927) (1)

Genus Lessinocamptus

Lessinocamptus caoduroi Stoch 1997 (1) *
Lessinocamptus insoletus (Chappuis 1928) (1) *
Lessinocamptus pivai Stoch 1997 (1) *

Family Leptopontidae

Genus Arenopontia
Subgen. Neoleptastacus

Arenopontia (Neoleptastacus) phreatica Cottarelli, Bruno & Venanzetti 1994 (2) *
Arenopontia (Neoleptastacus) speluncae Cottarelli, Bruno & Venanzetti 1994 (3) *

Genus Ichnusella

Ichnusella eione Cottarelli 1971 (2) *
Ichnusella pasquinii (Cottarelli 1969) (3) *
Ichnusella tertia Cottarelli et al., 1999 (3) *
Ichnusella longifurca Cottarelli et al., 1999 (2) *

Family Parastenocarididae

Genus Parastenocaris

Parastenocaris acherusia Noodt 1955 (1) *
Parastenocaris admete Cottarelli et al. 1980 (2) *
Parastenocaris amalasuntae Bruno & Cottarelli, 1998 (Bolsena Lake, central Italy) *
Parastenocaris amatheia Cottarelli 1970 (2) *
Parastenocaris amyclaea Cottarelli 1969 (3) *
Parastenocaris calliroe Cottarelli 1969 (2) *
Parastenocaris crenobia Galassi 1997 (3) *
Parastenocaris etrusca Cottarelli, Bruno & Venanzetti 1994 (3) *
Parastenocaris hera Cottarelli 1969 (3) *
Parastenocaris gertrudae Kiefer 1968 (1) *
Parastenocaris glacialis Noodt 1954 (3)
Parastenocaris ima Cottarelli 1989 (2) *
Parastenocaris italica Chappuis 1953 (1,3) *
Parastenocaris kalypso Pesce, Galassi & Cottarelli 1988 (5) *
Parastenocaris lorenzae Pesce, Galassi & Cottarelli 1988 (3) *
Parastenocaris oligoalina Cottarelli, Bruno & Venanzetti 1995 (2) *
Parastenocaris orcina Chappuis 1938 (3) *
Parastenocaris pasquinii Cottarelli 1972 (3) *
Parastenocaris proserpina Chappuis 1938 (3) *
Parastenocaris rivi Cottarelli & Bruno 1995 (2) *
Parastenocaris ruffoi Chappuis 1954 (1) *
Parastenocaris sardoa Cottarelli & Torrisi 1977 (2) *
Parastenocaris stellae Cottarelli, Saporito & Puccetti 1981 (2) *
Parastenocaris triphyda Cottarelli & Bruno 1994 (2) *
Parastenocaris tyrrhenidis Cottarelli 1970 (2) *
Parastenocaris trinacriae Pesce, Galassi & Cottarelli 1988 (5) *
Parastenocaris veneris Cottarelli & Maiolini 1980 (3) *