Aenigmachannidae, a new family of snakehead fishes (Teleostei: Channoidei) from subterranean waters of South India

Pronounced organism-wide morphological stasis in evolution has resulted in taxa with unusually high numbers of primitive characters. These ‘living fossils’ hold a prominent role for our understanding of the diversification of the group in question. Here we provide the first detailed osteological analysis of Aenigmachanna gollum based on high-resolution nano-CT scans and one cleared and stained specimen of this recently described snakehead fish from subterranean waters of Kerala in South India. In addition to a number of derived and unique features, Aenigmachanna has several characters that exhibit putatively primitive conditions not encountered in the family Channidae. Our morphological analysis provides evidence for the phylogenetic position of Aenigmachanna as the sister group to Channidae. Molecular analyses further emphasize the uniqueness of Aenigmachanna and indicate that it is a separate lineage of snakeheads, estimated to have split from its sister group at least 34 or 109 million years ago depending on the fossil calibration employed. This may indicate that Aenigmachanna is a Gondwanan lineage, which has survived break-up of the supercontinent, with India separating from Africa at around 120 mya. The surprising morphological disparity of Aenigmachanna from members of the Channidae lead us to erect a new family of snakehead fishes, Aenigmachannidae, sister group to Channidae, to accommodate these unique snakehead fishes.

Distribution of cyclopoid copepods in different subterranean habitats (southern Poland)

The majority of Polish studies on freshwater cyclopoids focused on surface water fauna. There are relatively few data on copepods of subterranean waters. Thus, in our research, copepods were collected from 37 different, mostly groundwater-dependent habitats (i.e. caves, springs, wells, interstitial and overhead environments) over a period of five years between 2005 and 2010. A total of 22 species belonging to eight genera were found. Some species, previously not recorded or known only from a few sites in Poland, proved to be a frequent component of subterranean communities.

Five new subterranean amphipods of the genus Pseudocrangonyx from Korea (Crustacea, Amphipoda, Pseudocrangonyctidae)

Although the majority of the species belonging to the genus Pseudocrangonyx Akatsuka & Komai, 1922 are found among the subterranean fauna of eastern Asia, the taxonomic knowledge is very poor and only four species have been recorded in Korea. In this study, the morphology of the stygobitic pseudocrangonyctid amphipods from Korean subterranean waters was examined and five new species were identified: Pseudocrangonyx concavussp. nov. has a characteristic emarginated posteroventral margin of epimeral plate 3; Pseudocrangonyx gracilipessp. nov. differs from other pseudocrangonyctids by the slender and elongated pereopods and more produced posterodistal corner of epimeral plate 3. Pseudocrangonyx crassussp. nov. shows the expanded peduncular articles and a reduced flagellum of antenna 2. Pseudocrangonyx minutussp. nov. is distinguished by more reduced pleopod articles compare to other pseudocrangonyctids. Pseudocrangonyx villosussp. nov. has the more setose bases of pereopods 3 and 4. Detailed descriptions and illustrations are presented for these five new species.

Groundwater Quality in Two Semi-Arid Areas of Algeria: Impact of Water Pollution on Biodiversity

The biodiversity and quality of subterranean waters were comparatively studied in the Tarf plain near Oum-El-Bouaghi and in the Ksar S’bahi in Oum-El-Bouaghi, in North-eastern Algeria. For this purpose, physicochemical and faunistic analyses were carried out on the water of ten stations located in the area of Tarf, and thirteen in the area of S’bahi. In the wells of Tarf, the average stygobiologic diversity was relatively high in the wells located upstream the dumping site from the city where the groundwater presented low contents of nitrates and orthophosphates. In contrast, the wells located in the spreading zone of Tarf wastewaters were characterized by the scarcity or the absence of stygobic species; in these latter wells, the water was highly polluted. It was rich in nitrates, nitrites, ammonium, and the conductivity was rather high. In the area of S’bahi, the faunistic inventory recorded ten species, some of which were living in hot springs. The subterranean water was highly mineralized. In the two studied areas, biodiversity decreased when well water was locally polluted.

Subterranean and Anchialine Waters

Crustaceans have successfully colonized the subterranean habitat, and many have become obligate inhabitants, occurring virtually everywhere there are interconnected voids underground. With the exception of most oniscidean isopods and a few talitrid amphipods, subterranean crustaceans inhabit water (stygobionts), where they dominate the stygofauna both in biomass and diversity of species. Four major taxonomic groups predominate: amphipods, isopods, copepods, and ostracods. Although most higher crustacean taxa have representatives in both epigean and subterranean habitats, some groups such as remipedes, thermosbaenaceans, spelaeogriphaceans, bathynellaceans, mystacocarids, and gelyelloid copepods are known only from the subterranean environment. Subterranean habitats vary physically and range from organically rich shallow habitats around seeps to cave systems more than a kilometer deep. Water quality, which can range from fresh to marine to hypersaline, static to flowing, and oxic to suboxic, impacts species distribution. Dispersal patterns in subterranean crustaceans are also diverse. Freshwater stygobiont crustaceans have narrow endemic ranges, and their dispersal is limited by saltwater. The distribution of several freshwater taxa might reflect the movement of tectonic plates. The extraordinarily diverse anchialine fauna, initially distributed along the Tethyan coast, was likely spread by vicariance due to movement of tectonic plates. Originating from epigean ancestors, many stygobionts have a marine origin. While the existence of preadaptations does not necessarily guarantee successful colonization of the subterranean habitat, a suite of characteristics is frequently observed in subterranean crustaceans, with most being weakly chitinized, lacking or with reduced eyes and pigments, and enhanced non-optic sense organs. Metabolic rates tend to be lower than in epigean crustaceans. Limited evidence indicates subterranean crustaceans are longer lived with lower reproductive potential. These adaptations make subterranean crustacean populations particularly vulnerable to anthropogenic impacts. The morphological, physiological, and life history adaptations to a subterranean existence are most likely common responses to the physical environment of each subterranean ecosystem. Extensive biodiversity and phylogeography studies are still required, and there is a pressing need to comprehend the functional role of stygofauna in subterranean waters.

Recentní vznik limonitové bahenní železné rudy v Hulíně (niva řeky Moravy)

There is described a new occurrence of mud limonite iron ore in this paper. Limonite originates recently in streams situated in flood plain of the Morava River near Hulín (central Moravia, Czech Republic). The chemical composition of precipitated limonite indicates that a contamination of subterranean waters by phosphorus, arsenic and some transitional metals (Cr, Zn) occurs here, very probably due to long-lasting intense agricultural usage of the surrounding fields. Based on experimental precipitation of limonite from local well water, a probable mechanism of formation of limonite was outlined. The Fe2+ ions, dissolved in the subterranean waters, are after their seepage into the stream oxidized by aerial oxygen to Fe3+, which is subsequently hydrolysed and precipitated in form of solid iron hydroxide. An important role of microorganisms and/or organic matter during precipitation of limonite is not suggested by collected data.