The distribution of stygobiontes in this province demonstrates the continuity of the Salentine Peninsula and the Murge ground waters, as well as the difficulty of faunal exchange between this area and the northern Gargano district. In this respect, a remarkable richness of groundwater animals, for the most part stygobiontes and endemites, occur in the Salento-Murge district; on the contrary, very few stygobitic taxa can be found in the Gargano district, from which mainly stygophilic or stygoxen, sometimes "thalassoid" elements, have been reported.
This province, as a whole, is characterized by a strikingly abundant and differentiated groundwater fauna, with a great number of ancient, specialized and rare stygobiontes, the majority of which are exclusive for this area, representing, as well, the most ancient and important elements of Italy’s stygofauna.
With the Apennine province, the Apulia shares only a few, recent stygobiontes or eustygophiles, such as some cyclopid and harpacticoid copepods (Diacyclops antrincola, Thermocyclops oblongatus, Diacyclops languidoides, Nitocrella stammeri, Parapseudoleptomesochra italica), the amphipods Niphargus longicaudatus, Niphargus orcinus s.l., Riphidogammarus rhipidiophorus and Salentinella angelieri, and numerous stygophilic or stygoxen taxa.
The stygobiontes of this province show different origin and geological age: the most ancient, such as the species of the genera Mixtacandona, Monodella, Spelaeomysis, Stygiomysis, Hadzia, Microcharon, Metaingolfiella, Typhlocaris, Salentinella (only the species S. gracillima) and the recently discovered subterranean sponges, are palaeomediterranean elements, that colonized the ground waters of Apulia during the "Tethys" period; other ones, such as the cyclopid copepods Halicyclops dalmatinus, Diacyclops antrincola, Thermocyclops oblongatus, Metacyclops stammeri and Laophonte spelaea, the amphipods Niphargus orcinus s.l., Pseudoniphargus adriaticus, Salentinella angelieri and Rhipidogammarus karamani colonized the underground aquatic environments of this province at a rather recent age, as it is shown by their marked euryhalinity or/and wide perimediterranean distribution; moreover, a significant number of stygobitic species are assumed to have colonized the Apulia ground waters according to the "Regression Model Evolution ".
As regards the origin of the remarkable ostracod Pseudolimnocythere hypogaea, according to Danielopol (1980) two current hypotheses can be proposed, viz. the species could have colonized the ground waters of Apulia during Miocene marine regressions, or in the course of Pleistocene regressive phase.
The apulian province shows a marked individuality due to the large extent and the peculiar characteristics of its carbonate rocks, as well as to the different groundwater systems that have evolved in them.