Sanda Iepure

Ostracod Assemblages in the Frasassi Caves and Adjacent Sulfidic Spring and Sentino River in the Northeastern Apennines of Italy

Rich, diverse assemblages comprising a total (live + dead) of twenty-one ostracod species belonging to fifteen genera were recovered from phreatic waters of the hypogenic Frasassi Cave system and the adjacent Frasassi sulfidic spring and Sentino River in the Marche region of the northeastern Apennines of Italy. Specimens were recovered from ten sites, eight of which were in the phreatic waters of the cave system and sampled at different times of the year over a period of five years. Approximately 6900 specimens were recovered, the vast majority of which were disarticulated valves; live ostracods were also collected. The most abundant species in the sulfidic spring and Sentino River were Prionocypris zenkeri, Herpetocypris chevreuxi, and Cypridopsis vidua, while the phreatic waters of the cave system were dominated by two putatively new stygobitic species of Mixtacandona and Pseudolimnocythere and a species that was also abundant in the sulfidic spring, Fabaeformiscandona ex gr. F. fabaeformis. Pseudocandona ex gr. P. eremita, likely another new stygobitic species, is recorded for the first time in Italy. The relatively high diversity of the ostracod assemblages at Frasassi could be attributed to the heterogeneity of groundwater and associated habitats or to niche partitioning promoted by the creation of a chemoautotrophic ecosystem based on sulfur-oxidizing bacteria. Other possible factors are the geologic age and hydrologic conditions of the cave and karst aquifer system that possibly originated in the early– middle Pleistocene when topographic uplift and incision enabled deep sulfidic waters to reach the local carbonate aquifer. Flooding or active migration would have introduced the invertebrates that now inhabit the Frasassi Cave system.

POSTNAUPLIAR ANTENNULAR DEVELOPMENT IN THE OBLIGATE SUBTERRANEAN ACANTHOCYCLOPS KIEFERI (CHAPPUIS, 1925) SPECIES-GROUP (KIEFER, 1927) (COPEPODA, CYCLOPOIDA)

The female antennule of several cyclopid copepods of the genus Acanthocyclops Kiefer, 1927 is known to have a high degree of oligomerization in both segmentation and chaetotaxy. The present work provides information on the ontogenetic development of the antennule of three (sub-)species of Acanthocyclops accommodated in the kieferi-group, with an 11- segmented antennule in the adult female. These are, A. balcanicus bisetosus Iepure, 2001, A. milotai Iepure & Defaye, 2008, and Acanthocyclops n. sp. Iepure & Oarga (unpubl.). One developmental pattern has been observed that results in an 11-segmented antennule through several successive enlargements and the addition of segments in the proximal section of the limb as follows: the first segment adds a new segment distally and an arthrodial membrane proximally during the moult to CIII; and the second segment adds a new segment distally during the moult to CIV and proximally in the moult to CV. The same (neotenic) morphology of CV is retained in the adult. The addition of segments and the distribution of setae on each segment were compared and homologized with two subterranean representatives of the genus Diacyclops Kiefer, 1927 that share the same pattern in the adult female, i.e., the D. clandestinus (Kiefer, 1926) sensu lato and the D. languidoides (Lilljeborg, 1901) sensu lato. The position of marker elements (i.e., dorsal seta (ancestral segment XV), medial distal seta (ancestral segment XX), etc.) in various copepodid stages is used to identify homologous segments. The analyses of antennula development suggest that segment number and chaetotaxy during development are characters that are less informative for phylogenetic studies in the genera Acanthocyclops and Diacyclops.