Biospeleologija

Biospeleology

BIOSPELEOLOGY IN CROATIA

The karst areas in Croatia, part of the Dinarides, have been defined biospeleologically as an area of high biodiversity in world terms, covering 26 000 km² in all. The biodiversity of subterranean habitats and their biota is primarily investigated from a taxonomic perspective, with a special attention being paid to regional diversity (Gottstein et al. 2002). The diversified geomorphology, hydrology and climate have resulted in a remarkable range of different underground habitats in Croatia, viz. inland and coastal caves, superficial and deep phreatic networks, interstitial – hyporheic substrates and other infiltration zones, etc. In Croatia more than 500 obligate subterranean species and subspecies are known from caves and interstitial habitats. The majority of subterranean species in Croatia are terrestrial biota. There are 299 troglobiont and 170 stygobiont taxa (species and subspecies) recorded. Most subterranean species have very restricted ranges, almost 70 % of them endemic to Croatia. Cave fungi are poorly known. Among them there are several important parasitic troglobionts and troglophilic species on cave coleopterans and troglophilic moths in Croatian caves. Some saprotrophic species could be troglobiotic too but their taxonomic and/or ecological status must be clarified in future research. With a respect to the number of troglobionts, the five largest animal groups are Coleoptera, Pseudoscorpiones, Araneae, Gastropoda and Diplopoda. The beetles (Coleoptera) are predominant. More than 100 cavernicolous beetles (species and subspecies) are known in Croatia. Among stygobionts, the Crustacea predominate. At least half of species described are Crustacea. Among Crustacea, the orders Syncarida and Thermosbaenacea are exclusively stygobiotic. Numerically, among crustacean stygobiotic Amphipoda dominate in caves and Copepoda in interstitial habitats. The only known stygobiotic sponge Eunapius subterraneus Sket et Velikonja inhabits several caves in Croatia. Also, the only known stygobiotic clam Congeria kusceri Bole inhabits a series of caves in Croatia. Other important groups include hydrozoa, planarians (Temnocephalida and Tricladida), snails (Mollusca: Gastropoda) and the only European stygobiotic Chordata Proteus anguinus Laurenti. The high taxonomic diversity of the subterranean biota of Croatia can be attributed partly to the geographical heterogeneity and a rather unique combination of various geological and ecological phenomena.

References:

Gottstein Matočec, S. (ed.), Bakran-Petricioli, T., Bedek, J., Bukovec, D., Buzjak, S., Franičević, M., Jalžić, B., Kerovec, M., Kletecki, E., Kralj, J., Kruzic, P., Kučinić, M., Kuhta, M., Matočec, N., Ozimec, R., Rađa, T., Štamol, V., Ternjej, I. & Tvrtković, N.: An overview of the cave and interstitial biota of Croatia. Nat. Croat., Vol. 11, Suppl. 1, 1-112, 2002, Zagreb.

NEWS

Croatian Endemic Stygobitic Freshwater Sponge Does Not Belong To The Genus Eunapius

Freshwater sponge which inhabits karst caves around Ogulin was described in 1986 as Eunapius subterraneus (Sket and Velikonja (1986) Stygologia 2, 254-266). So far it is the only known obligatory inhabitant of underground waters from the phylum Porifera and is therefore unique in the world. Twenty years old taxonomic position of this endemic stygobitic sponge is based primarily on the morphology of spicules. In order to better characterize this sponge, we have performed genetic analysis and determined primary structures of 18S rDNA, ITS2 (internal transcribed region 2) and cytochrome oxidase I (COI) mitochondrial gene. DNA sequences of the 3 diagnostic DNA regions were compared with the same DNA sequences from freshwater sponges belonging to the family Spongilidae. Our genetic analyses undoubtedly exclude this sponge from the genus Eunapius. E. subterraneus shows much higher genetic similarity with sponges from the genus Ephydatia. However, due to the unique changes in the primary structure of diagnostic DNA regions, this unique Croatian endemic sponge should probably be considered as the only known member of a new genus.

Reference:
Harcet, Matija; Bilandžija, Helena; Bedek, Jana; Gamulin, Vera.
Croatian Endemic Stygobitic Freshwater Sponge Does Not Belong To The Genus Eunapius // Zbornik sažetaka 9. hrvatskog biološkog kongresa = Proceedings of Abstracts of 9th Croatian Biological Congress / Višnja Besenorfer ; Goran I.V. Klobučar (ur.). Zagreb : Hrvatsko biološko društvo 1885, 2006. 200-201

The only stygobiotic sponge, known up to date, is Eunapius subterraneus including two subspecies E. subterraneus subterraneus Sket & Velikonja 1986 and E. subterraneus mollisparspanis Sket & Velikonja 1986. Since the first description of the species, when only three localities were known, the species was found in six additional localities. This research has been part of the project “ Conservation of Eunapius subterraneus, the only underground freshwater sponge in the world” , and it has been conducted in order to analyse morphological features and identify newly recorded populations, as well as to examine the current state of habitat quality and population-threatening changes. Samples were collected from six localities and specimens were examined morphometrically. The subspecies E. subterraneus subterraneus was recorded in three new localities. Subspecies E. subterraneus mollisparspanis was only found at the type locality. In Cave system Đula Medvedica population was not found, while research in Cave in quarry Tounj was not conducted because of risks due to high statical instability of the cave. Both localities are registered in the List of 10 most endangered karst phenomena in Croatia. Eunapius subterraneus is listed in the Red list of threatened plants and animals of Croatia, and, in addition, Ogulin as a part of distribution area is registered in 2003 as one of 10 most endangered karst ecosystems in the world by Karst waters institute (Washington, USA). These two facts indicate the need for urgent protection measures to save this unique element of Croatian fauna.

Reference:
Bilandžija, Helena; Bedek, Jana; Jalžić, Branko; Kerovec, Mladen; Gottstein Matočec, Sanja. Recent research of cave sponge Eunapius subterraneus Sket & Velikonja 1985 (Spongillidae Demospongia) // Book of Abstracts of the 18th International Symposium of Biospeleology, Cluj-Napoca, Romania, 10-15 July 2006. / Moldovan, Oana Teodora (ur.). Cluj-Napoca : Institutul de Speleologie „ ; Emil Racoviţă“ ; , International Society for Subterranean Biology, 2006. 66-67