The sensory basis of rheotaxis in the blind Mexican cave fish, Astyanax fasciatus

The sensory basis of rheotaxis (orientation to currents) was investigated in the blind Mexican cave fish, Astyanax fasciatus. An unconditioned rheotactic response to uniform velocity flows was exhibited, with a threshold of less than 3 cm s⁻¹. Disabling the entire lateral line or the superficial neuromast receptor class increased the rheotactic threshold to greater than 9 cm s⁻¹. A pharmacological block of the lateral line canal system alone had no effect. These results demonstrate that the superficial lateral line system controls rheotaxis at low current velocities. The effect of pairing an odor stimulant with the water current dropped the rheotactic threshold to less than 0.4 cm s⁻¹. This study provides a clear behavioral role for the superficial neuromasts where none previously existed, and also establishes a link between the mechanosensory lateral line and olfactory systems in the olfactory search behavior of the cave fish. Accepted: 9 January 1999     

Identification of roots in lava tube caves using molecular techniques: implications for conservation of cave arthropod faunas

Lava tube cave ecosystems on the volcanic islands of Hawai‘i support communities of rare and highly specialized cave arthropods. In these cave ecosystems, plant roots, both living and dead, provide the main energy source for cave animals. Loss of deep-rooted plants over caves will affect populations of cave-adapted animals living below. Furthermore, the loss of native plant species will likely eliminate host specific cave animals. Thus, identification of plant roots currently found in caves is necessary for the development of effective management actions that encourage the growth of appropriate deep-rooted plant species, thereby protecting the underlying cave ecosystem. We used molecular techniques to identify plant roots found within cave ecosystems on the islands of Maui and Hawai‘i. Sequences of the internal transcribed spacer (ITS) regions and the 5.8S gene of nuclear ribosomal DNA from cave roots were compared to sequences of known plant species either collected on the surface over the footprint of each cave or to sequences accessioned in GenBank. Roots in the cave ecosystem studied on Maui belonged to two alien tree species: Eucalyptus tereticornis and Grevillea robusta. Within the Hawai‘i cave ecosystem, roots of two plant species were identified: the alien tree G. robusta and the native vine Cocculus orbiculatus. The Maui cave ecosystem supports populations of at least 28 species of arthropods, including eight that are blind obligate cave inhabitants. The Hawai‘i cave ecosystem supports 18 arthropod species, of which three are cave-adapted. Creating protected reserves around biologically significant caves, controlling, and preventing the introduction of harmful invasive plant species within the cave footprint, and encouraging the establishment of deep-rooted native plant species is essential for the continued survival of the unique ecosystems found within Hawaiian lava tube cave systems.     

Evolutional process and depositional cycles of Peking Man Cave in relation to the living environments and cultural development of Peking Man

Evolutional process of the Peking Man Cave, from funnel and vertical channel development in the Early Pliocene to the cave close in the late Middle Pleistocene, may be divided into six stages. Cave deposits in filling process of the cave from Layer 13 to Layer 1 can be divided into seven depositional cycles. These cycles allow a correspond with the loess sequences S7-L2 in China and oxygen isotope stages 19-6 of climatic cycles I-C of deep sea records. The living environments and cultural development of Peking Man in closely related to the cave environments of each stage in evolutional process and each cycle in depositional process of the cave are researched in this paper. The cave evolutional process has gone through about 4 Ma. The Peking Man start entered into the cave and made stone implements before 580 ka B.P. The cultural development of Peking Man may be divided into the early, middle and late three stages about in 580–420 ka, 420–340 ka and 340–250 ka, respectively. Peking Man's first used fire is about 530 ka B.P. Habitation of Peking Man concetrated in the western part of the cave after 340 ka B.P. when eastern cave roof was collapsed. Peking Man left the cave after 250 ka B.P. during the cave was continuous collapsed and almost filled up.     

Culturable Microbial Diversity and the Impact of Tourism in Kartchner Caverns,Arizona

Kartchner Caverns in Benson, AZ, was opened for tourism in 1999 after a careful development protocol that was designed to maintain predevelopment conditions. As a part of an ongoing effort to determine the impact of humans on this limestone cave, samples were collected from cave rock surfaces along the cave trail traveled daily by tour groups (200,000 visitors year^–1) and compared to samples taken from areas designated as having medium (30–40 visitors year^–1) and low (2–3 visitors year^–1) levels of human exposure. Samples were also taken from fiberglass moldings installed during cave development. Culturable bacteria were recovered from these samples and 90 unique isolates were identified by using 16S rRNA polymerase chain reaction and sequencing. Diversity generally decreased as human impact increased leading to the isolation of 32, 27, and 22 strains from the low, medium, and high impact areas, respectively. The degree of human impact was also reflected in the phylogeny of the isolates recovered. Although most isolates fell into one of three phyla: Actinobacteria, Firmicutes, or Proteobacteria, the Proteobacteria were most abundant along the cave trail (77% of the isolates), while Firmicutes predominated in the low (66%) and medium (52%) impact areas. Although the abundance of Proteobacteria along the cave trail seems to include microbes of environmental rather than of anthropogenic origin, it is likely that their presence is a consequence of increased organic matter availability due to lint and other organics brought in by cave visitors. Monitoring of the cave is still in progress to determine whether these bacterial community changes may impact the future development of cave formations.     

Mesolithic burials in los canes cave (Asturias,Spain)

Los Canes is a small cave situated half way up the abrupt southern slope of Cuera range, near the village of Arangas (Eastern Asturias, Spain). Three funerary structures have been discovered in the entrance of that cave. They consisted of burials (one of them, number II, reused) where the corpses of three individuals had been placed in different positions, with the legs strongly bent. Various grave goods (animal bones, pierced teeth, a perforated antler, etc.) accompanied them. The individuals found in these burials have been directly dated by AMS. Their age ranges between 6930±95 and 6265±75 BP (5930–5680 and 5330–5010 cal. BC). The present paper describes in detail the burials and discusses the questions raised by their datations and characteristics. Fourthermore the authors compare them with other Cantabrian funerary structures, taken into account the different mesoecological factors and living conditions of these last hunter-gatherer populations. Some preliminary anthropological data about Los Canes individual n^oI are also considered.     

Isotopic evidence for methane-based chemosynthesis in the Upper Floridan aquifer food web

Anecdotal observations of the Dougherty plain cave crayfish (Cambarus cryptodytes), the Georgia blind cave salamander (Haideotriton wallacei), and albinistic isopods (Caecidotea sp.) at great depths below the land surface and distant from river corridors suggest that obligate aquifer-dwelling (troglobitic) organisms are widely distributed throughout the limestone Upper Floridan aquifer (UFA). One mechanism by which subterranean life can proliferate in an environment void of plant productivity is through a microbial food web that includes chemosynthesis. We examined this possibility in the UFA by measuring the isotopic composition (¹³C, ¹⁴C, and ¹⁵N) of tissues from troglobitic macrofauna. Organisms that were captured by cave divers entering into spring conduits had δ¹³C values that suggested plant matter as a primary food resource (cave crayfish, –24.6 ± 2.7‰, n = 9). In contrast, δ¹³C values were significantly depleted in organisms retrieved from wells drilled into areas of the UFA remote from spring and sinkhole conduits (cave crayfish −34.7 ± 9.8‰, n = 10). Depleted ¹³C values in crayfish were correlated with radiocarbon (Δ¹⁴C) depletion relative to modern values. The results suggest that methane-based microbial chemosynthetic pathways support organisms living in the remote interior of the aquifer, at least in part.     

Cave molly females (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>) avoid parasitised males

Cave mollies (Poecilia mexicana) inhabit a dark Mexican cave, where visual communication is impossible. I observed the preference of cave molly females to associate with a non-infected male or a male infected with a pathogenic bacterium (Mycobacterium sp.) which causes the formation of large blisters around the eyes of infected fish. Females preferred to stay near the non-infected male only when the two stimulus males were separated from the female by transparent Plexiglas in light, but not when the males were separated by a wire-mesh in light (where vision was to some extent hindered, but the females perceived non-visual cues) or in darkness (where only non-visual cues were available). I conclude that the visually mediated preference for non-infected males has been maintained during the colonisation of the lightless habitat, but a preference for this trait on the basis of non-visual cues did not evolve. The cave habitat may be poor in pathogens, resulting in low selection pressure to evolve a non-visual preference for males without bacterial infection.Communicated by R.F. Oliveira     

Upper Pleistocene Panthera leo spelaea (Goldfuss, 1810) remains from the Bilstein Caves (Sauerland Karst) and contribution to the steppe lion taphonomy,palaeobiology and sexual dimorphism

Remains of the steppe lion Panthera leo spelaea (Goldfuss) from historical digs in the Bilstein Caves of Warstein (Sauerland, NW Germany) are described. Their age seems to be from the Early Weichselian periods (Upper Pleistocene). Whereas the Bilstein cave was inhabited by cave bears at that time only a few hyena prey remains, were most likely imported into the cave entrance by hyenas. Bite and crush marks on a few bones of Bison priscus, Bos primigenius, Cervus elaphus, a rhinoceros Coelodonta antiquitatis vertebra and even several chewed cave bear bones prove the hyena presence which is similar to other caves in the Sauerland hyena den cave rich region. Additionally some larger wolves subspecies Canis lupusspelaeus bones were found, but only few Crocuta crocuta spelaea remains are present. After taphonomic comparisons to six other hyena and cave bear den caves of northern Germany, this cave can be classified as a cave bear den, which was briefly used by hyenas only for food storage or commuting or cave bear predation site in one part of the Cave. The lion material refers at least to one young adult lioness, one more adult female and two male lions; therefore, at minimum, the remains of four adult individuals are represented. The absence of juvenile lion material, in contrast to cave bear cub remains in the Bilstein Caves, proves that P. leo spelaea did not use this and all other caves in the region to raise their cubs. The bone material from the Bilstein Caves would prove the same hyena-lion antagonism conflict being recently proven for the Perick Caves, Balve Cave or Martins Cave well. Other situations in caves such as the Keppler Cave and the Bilstein Cave initially show the more complex taphonomic situation of lion remains in European caves, especially in cave bear dens, where they seem to have hunted periodically cave bears, such as it is already proven for hyenas in the Sauerland Karst and other caves of Europe.     

Les faunes des sites du Pléistocène supérieur du Caucase méridional : Grotte de Saka?hia, Grotte d’Ortvala et Grotte du Bronze (République de Géorgie)

The paleontological analysis of the fauna from three Late Pleistocene localities in Southern Caucasus (Saka?hia, Ortvala, and Bronze cave) confirmed the presence of Ursus spelaeus, Canis lupus, Equus ferus, Rhinocerotidae, Cervus elaphus, Capreolus capreolus, Alces alces, Bison priscus, Capra caucasica, Ovis ammon and Sus scrofa. The study also permitted the identification of new taxa for these localities. There may be the presence of reindeer (Rangifer tarandus) at Saka?hia, however it has not yet been confirmed. Moreover, remains of aurochs (Bos primigenius) were identified, in particular at Bronze cave where its abundance is exceptional. Indeed, Bos and Bison are generally very rare in Southern Caucasus. The analysis of the proportion of the different species in each locality revealed the two types of occupations of the caves, one dominated by hominids and the other by carnivores. At Saka?hia, where fauna is dominated by the presence of cave bear, the cave was seasonally occupied by Neanderthal groups. On the other hand, Bronze cave corresponds to a habitat of hunters, which occupied the site for longer periods.     

Ancient Photosynthetic Eukaryote Biofilms in an Atacama Desert Coastal Cave

Caves offer a stable and protected environment from harsh and changing outside prevailing conditions. Hence, they represent an interesting habitat for studying life in extreme environments. Here, we report the presence of a member of the ancient eukaryote red algae Cyanidium group in a coastal cave of the hyperarid Atacama Desert. This microorganism was found to form a seemingly monospecific biofilm growing under extremely low photon flux levels. Our work suggests that this species, Cyanidium sp. Atacama, is a new member of a recently proposed novel monophyletic lineage of mesophilic “cave” Cyanidium sp., distinct from the remaining three other lineages which are all thermo-acidophilic. The cave described in this work may represent an evolutionary island for life in the midst of the Atacama Desert.     

The largest European lion Panthera leo spelaea (Goldfuss 1810) population from the Zoolithen Cave,Germany: specialised cave bear predators of Europe

Remains of 13 individuals with 3/1 male/female ratio of the extinct Upper Pleistocene lion Panthera leo spelaea (Goldfuss, 1810) from the Zoolithen Cave near Burggeilenreuth (Bavaria, Germany) include the holotype skull and all paratype material. The highest mortality rate for the Zoolithen Cave lions is in their reproductive adult ages. Bite marks on lion bones or skulls are results of hyena activities, or rare cannibalism of lions under stress situations. Lions were possibly also killed in battles with cave bears during predation on hibernating bears in winter times. This cave bear hunt specialisation in caves overlaps with the ecological behaviour of cave bear feeding by Ice Age-spotted hyenas. Both largest Ice Age predators, lions and hyenas, had to specialise on feeding herbivorous cave bears in boreal forest mountainous cave rich regions, where the mammoth steppe megafauna prey was absent. This cave bear hunt by felids, and scavenging by hyenas and other large carnivores such as leopards and wolves explains why cave bears hibernated deep in to the European caves, for protection reasons against predators. Within such lion–cave bear and even lion–hyena conflicts in the caves lions must have been killed sometimes, explaining mainly the skeleton occurrences in different European caves.     

Comparing bacterial community fingerprints from white colonizations in Altamira Cave (Spain)

Monitoring bacterial communities is critical for assessing biodeterioration among other processes. This study presents a strategy and an example of comparative analysis of bacterial communities developing in a cave environment, Altamira Cave which contains unique paleolithic paintings. The analyzed question was whether white colonizations discovered throughout the cave corresponded to similar or different bacterial communities. Molecular fingerprints were obtained by PCR–DGGE from DNA and RNA and statistically compared. Results based on DNA analysis showed that a similar bacterial community was present in white colonizations throughout the cave. Fingerprints based on RNA confirmed the similarity of the major metabolically active components of these communities. The proposed procedure confirmed that white colonizations in Altamira Cave were a consequence of the development of a single complex bacterial community, and the method proves to be highly useful for comparative analysis of microbial communities, including biodeteriorating processes and any other comparative analysis of bacterial communities.     

Bacteria Associated with the Bleached and Cave Coral Oculina patagonica

The relative abundance of bacteria in the mucus and tissues of Oculina patagonica taken from bleached and cave (azooxanthellae) corals was determined by analyses of the 16S rRNA genes from cloned libraries of extracted DNA and from isolated colonies. The results were compared to previously published data on healthy O. patagonica. The bacterial community of bleached, cave, and healthy corals were completely different from each other. A tight cluster (>99.5% identity) of bacteria, showing 100% identity to Acinetobacter species, dominated bleached corals, comprising 25% of the 316 clones sequenced. The dominant bacterial cluster found in cave corals, representing 29% of the 97 clones sequenced, showed 98% identity to an uncultured bacterium from the Great Barrier Reef. Vibrio splendidus was the most dominant species in healthy O. patagonica. The culturable bacteria represented 0.1–1.0% of the total bacteria (SYBR Gold staining) of the corals. The most abundant culturable bacteria in bleached, cave, and healthy corals were clusters that most closely matched Microbulbifer sp., an α-proteobacterium previously isolated from healthy corals and an α-protobacterium (AB026194), respectively. Three generalizations emerge from this study on O. patagonica: (1) More bacteria are associated with coral tissue than mucus; (2) tissue and mucus populations are different; (3) bacterial populations associated with corals change dramatically when corals lack their symbiotic zooxanthellae, either as a result of the bleaching disease or when growing in the absence of light.     

Life on the edge: hydrogen sulfide and the fish communities of a Mexican cave and surrounding waters

Most eucaryotic organisms classified as living in an extreme habitat are invertebrates. Here we report of a fish living in a Mexican cave (Cueva del Azufre) that is rich in highly toxic H₂S. We compared the water chemistry and fish communities of the cave and several nearby surface streams. Our study revealed high concentrations of H₂S in the cave and its outflow (El Azufre). The concentrations of H₂S reach more than 300 μM inside the cave, which are acutely toxic for most fishes. In both sulfidic habitats, the diversity of fishes was heavily reduced, and Poecilia mexicana was the dominant species indicating that the presence of H₂S has an all-or-none effect, permitting only few species to survive in sulfidic habitats. Compared to habitats without H₂S, P. mexicana from the cave and the outflow have a significantly lower body condition. Although there are microhabitats with varying concentrations of H₂S within the cave, we could not find a higher fish density in areas with lower concentrations of H₂S. We discuss that P. mexicana is one of the few extremophile vertebrates. Our study supports the idea that extreme habitats lead to an impoverished species diversity.     

Phototactic response and light sensitivity in an epigean and a hypogean population of a barb (Garra barreimiae, Cyprinidae)

We investigated the response of two populations of the barb Garra barreimiae to different light intensities (0.5–2000 lx) from a light source. Adults of both the surface (epigean) and cave (hypogean) G. barreimiae populations show photophobic behavior. A photophobic response in the cave form was seen only at higher light intensities because the cavefish are eyeless and rely on extra-retinal light receptors to detect light. In contrast, juveniles (surface and cave) showed photophilic behavior, and their preference for the photic zone of the test tank decreased with increasing age. We discuss the potential role played by photophobic behavior for the colonization of caves by previously surface-dwelling fishes.     

Paleoecological and microenvironmental aspects of the first European hominids inferred from the taphonomy of small mammals (Sima del Elefante,Sierra de Atapuerca,Spain)

Unit TE9 of the Sima del Elefante (Sierra de Atapuerca, Burgos, Spain), where the remains of Homo sp. have been discovered (1.2–1.3 Ma), is also a level rich in small mammals. The taphonomic study of these small vertebrates sheds light on the landscape that provided the setting for the activities of these early hominids and allows us to describe what the cave was like during the formation of the level. Small mammal predators identified in the study indicate that during this period the Sierra de Atapuerca was part of a large biome consisting of semi-open riparian forests with meadows nearby. Postdepositional alterations reveal that the production of fossils took place outside the cave, being transported inside by water currents. During the formation of TE9, the cave presented conditions of high humidity, which made it difficult for hominids to establish occupations inside, although these conditions became somewhat less severe in TE9c, the sublevel where human remains are found.     

A Millennium of Human Activity at Makauwahi Cave, Māhāūulepū, Kauaūi

A cave system in the eolianite deposits of the Māhā′ulepū/Pā′ā area of Kaua′i, Hawai′i, contains a rich fossil record of prehuman Holocene conditions and also preserves a thousand-year record of human activity. Details concerning pre-Contact Polynesian life have been extracted from subaqueous middens and artifacts, including perishable materials such as wood, gourd, and cordage. Oral traditions concerning the cave and vicinity generally show good agreement with the archaeological and paleoecological record and provide rich stories said to derive from as early as the fourteenth century A.D. Fossil evidence highlights biotic and landscape changes before, during, and after initial Polynesian and subsequent European settlement. The approximate temporal coincidence of evidence for human arrival and last occurrence of some now-extinct species is too great to ignore the possibility that humans played a role in some extinctions of native taxa before European colonization. Old maps, an 1824 sketch, records of the Land Court Awards, and old photographs confirm stratigraphic inferences and oral accounts concerning demographic and ecological conditions of the early historical period. Feral livestock proliferated in the nineteenth and early twentieth centuries, with loss of vegetative cover to overgrazing, decline of most of the native flora, and subsequent dune reactivation. Sedimentation rates reach their peak later in the twentieth century after the establishment of agricultural and mining operations nearby.     

A comparison of the leaf shredding ability and influence on microbial films of surface and cave forms of <Emphasis Type="Italic">Gammarus minus</Emphasis> Say

Gammarus minus has both cave and surface forms that differ considerably in their morphology. We experimentally compared the ability of these two forms to consume leaves and influence the activity of the microbial films associated with leaves. Both forms of G. minus were effective leaf shredders, and were equally efficient at converting leaves to small particles. We found little relationship between amphipod size and the rate at which they shredded leaves. Both forms of G. minus stimulated the respiration rate of microbes associated with leaves by 32–52%. Cave forms of G. minus had a 15% greater stimulatory effect on microbial respiration. The stimulatory effect of G. minus on microbial respiration is evident in cave streams as well as in the laboratory. It appears that G. minus plays a particularly important role in cave systems by converting leaves to fine particles and stimulating microbial films which are important foods for many cave animals. Handling editor: D. Ryder     

Shape variation in surface and cave populations of the armoured catfishes Ancistrus(Siluriformes: Loricariidae) from the São Domingos karst area, upper Tocantins River, Brazil

Body shape of four distinct populations of Ancistrus cryptophthalmus from different caves in the São Domingos karst area and the local epigean (surface) Ancistrus species were compared using geometric morphometrics. Angélica and Bezerra catfishes were closer to each other and successively to the studied sample of epigean catfishes than to Passa Três and São Vicente I catfishes. Greater similarity between catfishes from the Angélica‐Bezerra cave system to epigean catfishes than to other cave catfishes may represent a plesiomorphic feature. On the other hand, the present analyses allowed the distinction between Passa Três and São Vicente I catfishes, which inhabited the same cave system. Topographic isolation due to the presence of several waterfalls interposed between the stream reaches where these catfishes live may explain such morphological differentiation. Also, the presence of a waterfall downstream of the reach where the Angélica sample was obtained may have contributed to the partial isolation of these catfishes from those living in Bezerra Cave. Differences in population sizes probably influenced the degrees of morphological differentiation observed among the cave populations. The mosaic distribution of character states indicated that the four populations of A. cryptophthalmus have evolved rather independently, but the continuous variation suggests a recent connection between these populations, perhaps with a limited gene flow. Considering other features such as reduction of eyes and pigmentation, and changes in body shape, a separate species status for the epigean and hypogean Ancistrus species from the São Domingos karst area has been maintained.     

The Crocuta crocuta spelaea (Goldfuss 1823) population and its prey from the Late Pleistocene Teufelskammer Cave hyena den besides the famous Paleolithic Neandertal Cave (NRW,NW Germany)

Remains from at least seven individuals of the Late Pleistocene Ice Age spotted hyena Crocuta crocuta spelaea (Goldfuss, 1823) from the Teufelskammer Cave in the Neandertal valley (North Rhine-Westphalia, northwest Germany) are described. The small cave was a well-frequented hyena den of the Early to Middle Late Pleistocene which was only 100 m from the famous small Feldhofer Cave, where the first Neandertal human skeleton was found. The high amount of hyena bone material (37%) and its strongly chewed and incomplete prey remains of the mixed mammoth steppe and boreal forest megafauna prove one more of 11 recently known hyena den caves in the Rhenish Massif. Hyenas and cave bears have used the cave, but Neandertal humans lived possibly not at the same time in the same valley. Although hyenas occupied mainly the smaller caves such as the Teufelskammer Cave, humans preferred large portal cave entrances such as in the Neandertal valley with the Small Feldhofer Cave.