Despite its inhospitable appearance and lack of any ... - Udine Cultura

More documents

Recommendations

Info

66 amber, implying a perhaps more ancient origin. Almost all species are endemic and live in the Alps and Po Plain, in several distinct, although not welldefined phyletic lines (the main groups being stygius, kochianus, aquilex and bajuvaricus). The diversity of the genus decreases proceeding southwards down the Apennines, with species belonging to the groups speziae (northern and central Apennines), longicaudatus (throughout the Apennines, Sicily, Sardinia, and smaller islands), and orcinus. This last group includes species similar to Balkan ones (exclusively associated with karstic aquifers), which colonised Italy from the Julian karst in the north-east and, perhaps through trans-Adriatic pathways, the limestone systems of the central-southern Apennines and Apulia. In addition to these groups, there are several species of unknown affinity, like Niphargus stefanellii (found in caves in centralsouthern Italy), which seems related to Balkan species, and colonises even sulphureous waters. Niphargus species, which are greatly diversified in structure and size, colonise all types of underground habitats. In large alkaline karstic lakes, species are large (2-4 cm) with elongated antennae and other appendages, and large anterior claw-shaped limbs (gnathopods) for seizing prey (Niphargus steueri, N. tridentinus). Interstitial environments host small omnivorous species (3-10 mm) with globose (Niphargus pupetta, N. transitivus) or elongated, worm-like bodies (Niphargus bajuvaricus grandii, N. italicus). Other species colonise subsurface, non-karstic aquifers, and may even be found in moist soil. They have tapering bodies, like N. dolenianensis and various species of the group longicaudatus. Italy also hosts the only species of the related genus Carinurella (C. paradoxa), which has a globose body with stumpy appendages and lives in interstitial waters of Friuli Venezia Giulia. Salentinellids. This is possibly a palaeo-Mediteranean amphipod family that comprises only stygobionts deriving from marine ancestors, whose identity is still uncertain. Salentinella species are still undergoing revision, and the most common species, S. angelieri, is typically interstitial and lives in brackish water near the coastline. It is also found in caves of isolated karstic systems and in true continental groundwater, with other species like S. franciscoloi of Liguria. Salentinella gracillima is exclusive to groundwater in Apulia. Ingolfiellidae. This family includes many stygobionts with elongated bodies living in marine and freshwater interstitial environments. So far, only one species has been found in Italian fresh groundwaters: Ingolfiella (Tyrrhenidiella) cottarellii, from a cave on the island of Tavolara (off the northeastern coast of Sardinia). Metaingolfiellids. The family comprises the single species Metaingolfiella mirabilis, which is quite large (3 cm). Many specimens of this species were collected, on a single occasion, from water pumped out of a deep karstic well in Salento. Described in 1969, it has never been found since. It is perhaps one of the most ancient palaeo-endemics of Italian fauna. Its body structure and the shape of its gnathopods suggest that it is a predator. Pseudoniphargids. This family includes only stygobionts, and is particularly diversified in the Mediterranean area. In Italy, only a few species are known, living in interstitial environments and caves near the coastline, showing their marine origin. Two species (Pseudoniphargus africanus italicus, P. sodalis) live in Sicily, and one (P. planasiae) in the Tuscan archipelago. Pseudoniphargus adriaticus has been collected in wells near Bari, and is also known to inhabit the Pelagian Islands (between Sicily and Tunisia), although its taxonomic status is uncertain. Other specimens, collected in Sardinia, are still being examined. Metacrangonyctids. This family is distributed around the Atlantic, includes only stygobionts, and is very diversified in the Mediterranean area. Italy hosts only Metacrangonyx ilvanus, endemic to the island of Elba, where it was recently found only in one well in alluvial groundwaters. Salentinella angelieri (ca. 30x) 67
68 ■ Decapods Italian fauna has only two stygobiont decapod genera living in karstic waters: Troglocaris (Isonzo and Trieste Karst) and Typhlocaris (Apulia). Recent research has revealed that Italian caves actually host two species of shrimps of the genus Troglocaris of the anophthalmus group, morphologically difficult to distinguish, but easily Troglocaris anophthalmus identified by means of molecular biology techniques. They may belong to T. anophthalmus (Gorizia Karst) and T. planinensis (Trieste Karst), although their taxonomy still requires Typhlocaris salentina confirmations. Stygobiont species of the genus Troglocaris were thought to derive from marine ancestors. Very recent molecular biology analyses carried out at the University of Ljubljana (Slovenia) have dated the separation of the western anophthalmus group from the Dinaric-Caucasian one at between 6 and 11 million years ago, and the beginning of speciation within the anophthalmus group between 3.7 and 5.3 million years ago. Their marine origin is therefore very ancient, and populations colonised groundwater coming from surface freshwater. The third species of Italian stygobiont decapods, Typhlocaris salentina, is endemic to Apulian caves. It was discovered in the Grotta Zinzulusa at Castro Marina in 1922, and later collected from other caves in Salento, Murge and Gargano. This blind, depigmented prawn may reach exceptional sizes (up to 13 cm); a predator, it feeds on mysidaceans and stygoxene organisms. The genus Typhlocaris includes two stygobiont species living in groundwater in Israel and Libya, suggesting that it is an ancient relict of an otherwise extinct palaeo-Mediterranean pre-Pliocene surface fauna associated with a subtropical climate. Unfortunately, molecular data on this genus are not yet available. ■ Amphibians The olm (Proteus anguinus) is the only stygobiont amphibian of the Palaearctic fauna. The pétit dragon of the Postojna caves (Slovenia) - discovered by the Slovenian nobleman Valvasor in 1689 and briefly described by Laurenti in 1768 - is the best-known underground animal described so far and, in some ways, the most fascinating. It has a pinkish-white eel-shaped body, with atrophic eyes concealed under the skin and outer red gill plumes which it retains throughout its life. The olm is known for its neoteny, i.e., it reaches precocious reproductive maturity despite its larval appearance. Olms are predators feeding on other aquatic, even stygoxene animals; the females lay between 20 and 80 eggs, one at a time for over one month, and place them under rocks and stones. The greyish tadpoles have distinct eyes, which they retain until they are two months old. Until the age of three months, olms feed exclusively on yolk stored in the cells of their digestive tracts. In nature, reproduction seldom occurs before the tenth year of age. The origin of olms is debated. Fossils of proteids and iguanodonts, found at Bernissart in Belgium, date back to the Lower Cretaceous, when olms lived in surface water. Their colonisation of karstic groundwaters in the Dinaric area where they now live may have started in the Pliocene, when karstification began. In 1994, in the Slovenian Karst, a pigmented, eyed subspecies was Olms also live in the groundwaters of the Isonzo Karst 69
Page 1 and 2: Fauna FABIO STOCH Despite its inhos
Page 3 and 4: 44 45 Methods for sampling and anal
Page 5 and 6: 48 Shells of gastropods Iglica voba
Page 7 and 8: 52 collected in phreatic waters in
Page 9 and 10: 56 ● Cyclopoid copepods. So far,
Page 11 and 12: 60 those associated with percolatin
Page 13: 64 Species of genus Niphargus; top:
Page 17 and 18: 72 Stygofaunal provinces in Italy T
Page 19 and 20: 76 aquifers in the Sabini mountains
Page 21 and 22: 80 ■ The ecology of aquifers Acco
Page 23 and 24: 84 85 The discovery of a new submer
Page 25 and 26: 88 anastomoses, often adjacent to t
Page 27 and 28: 92 93 The saline springs of Poiano:
Page 29 and 30: 96 Modified sensory setae on the an
Page 31 and 32: 100 Theoretical evolutionary sequen
Page 33 and 34: 104 Sketch showing degrading phases
Page 35 and 36: 108 109 Stygodiversity in the Presc
Page 37: 112 animal groups still living on t

Despite its inhospitable appearance and lack of any ... - Udine Cultura

Create successful ePaper yourself

Delete template?

Save as template?