Marine Caves Research Articles

Cryptic habitats and cryptic diversity: unexpected patterns of connectivity and phylogeographical breaks in a Mediterranean endemic marine cave mysid.

The marine cave-dwelling mysid Hemimysis margalefi is distributed over the whole Mediterranean Sea, which contrasts with the poor dispersal capabilities of this brooding species. In addition, underwater marine caves are a highly fragmented habitat which further promotes strong genetic structuring, therefore providing highly informative data on the levels of marine population connectivity across biogeographical regions. This study investigates how habitat and geography have shaped the connectivity network of this poor disperser over the entire Mediterranean Sea through the use of several mitochondrial and nuclear markers. Five deeply divergent lineages were observed among H.margalefi populations resulting from deep phylogeographical breaks, some dating back to the Oligo-Miocene. Whether looking at the intralineage or interlineage levels, H.margalefi populations present a high genetic diversity and population structuring. This study suggests that the five distinct lineages observed in H.margalefi actually correspond to as many separate cryptic taxa. The nominal species, H.margalefi sensu stricto, corresponds to the westernmost lineage here surveyed from the Alboran Sea to southeastern Italy. Typical genetic breaks such as the Almeria-Oran Front or the Siculo-Tunisian Strait do not appear to be influential on the studied loci in H.margalefi sensu stricto. Instead, population structuring appears more complex and subtle than usually found for model species with a pelagic dispersal phase. The remaining four cryptic taxa are all found in the eastern basin, but incomplete lineage sorting is suspected and speciation might still be in process. Present-day population structure of the different H.margalefi cryptic species appears to result from past vicariance events started in the Oligo-Miocene and maintained by present-day coastal topography, water circulation and habitat fragmentation.

A new species of the alpheid shrimp genus Triacanthoneus Anker, 2010 (Crustacea: Alpheidae) from Belize.

A new species of the alpheid shrimp genus Triacanthoneus Anker, 2010, is described based on material collected in a marine cave off Caye Chapel, Belize. Triacanthoneus chapelianus sp. nov. is the fifth species in the genus and can be distinguished from the other four species by the position of the dorsolateral teeth on the carapace, which in the new species have an anterior (= submarginal) position, and by the configuration of the posterior margin of the telson, with a notch in the middle portion and two pairs of spines and one pair of plumose setae. A key to the five species of Triacanthoneus is provided.

Molecular and distribution data on the poorly known, elusive, cave mysid Harmelinella mariannae (Crustacea: Mysida)

AbstractMediterranean underwater marine caves harbour abundant populations of several species of mysids that are increasingly used as biological models in ecological and evolutionary studies. One exception is the species Harmelinella mariannae, described in 1989 and then hardly ever again reported in the literature. We here provide the first data on the distribution of this poorly known taxon that, contrary to expectations for a rare brooding cave dweller, we now report from Madeira Island in the nearby Atlantic, to the easternmost parts of the Mediterranean. Brief behavioural observations are added, particularly its atypical solitary habits and its feeding behaviour as a high trophic level carnivore. Molecular characterization of the different specimens captured provided three sorts of information. Mitochondrial COI and 16S haplotypes suggest different colonization waves in the Mediterranean, with one group in the Eastern Basin, two in the Marseille region in the NW part of this sea, and another group with a very wide extension from Madeira to Liguria and Malta. Mitochondrial data also support that one of the groups in Marseille might have diverged as a cryptic species of Harmelinella. 18S rRNA gene displays a single common sequence to all specimens from the four groups, and seems to confirm the original proposed placement of this taxon within the subfamily Heteromysinae, not Leptomysinae.

Mobile epifaunal community in marine caves in comparison to open habitats

Mobile epifauna is an essential component of rocky reef ecosystems. In spite of this and the great scientific interest that the study of marine caves has aroused in the last decades, lit- tle research has been conducted on the macrofauna associated with animal substrates in subma- rine caves. This study explores the main differences between marine caves and open habitats in terms of species composition and diversity patterns of epifaunal communities in 4 different shal- low marine caves in southern Spain. Colonies of Eudendrium sp., a marine hydroid widely distrib- uted in the Mediterranean Sea, were taken from inside and outside each cave, and all associated mobile fauna were sorted and identified. More than 90% of organisms were crustaceans, with Amphipoda as the dominant group. Although the main species did not vary significantly in abun- dance between open and cave habitats, multivariate analysis carried out for the entire amphipod community showed significant differences between these 2 habitats. nMDS analysis showed that marine cave assemblages were also characterized by a higher degree of individuality, and uni- variate analysis showed a decrease in Shannon diversity and species richness with distance into the caves, a consistent pattern for all caves studied. Although the possible role of predation pres- sure in the structure of such assemblages was also discussed, we propose that the absence of plant substrates inside the caves, in conjunction with oligotrophic conditions and low siltation, are the main factors responsible for the impoverishment of the epifaunal community. The near lack of photosynthetic activity reduced the presence of herbivorous species, while the rich detritus-feeder community supported by the animal substrates was limited by the low rate of sedimentation.

Mediterranean fish—<I>Gammogobius steinitzi</I> Bath, 1971 (Actinopterygii: Perciformes: Gobiidae)—a new representative of the Black Sea ichthyofauna

Gammogobius steinitzi Bath, 1971, a goby species endemic to the Mediterranean Sea, was observed for the first time in the Black Sea in marine caves of western Crimea (Tarkhankut, Ukraine). A description of the morphological and ecological characteristics is given on the basis of the analyses of 5 specimens. The morphological and ecological characteristics of the Black Sea specimens do not differ from the Mediterranean ones.

Ecoregion-Based Conservation Planning in the Mediterranean: Dealing with Large-Scale Heterogeneity

Spatial priorities for the conservation of three key Mediterranean habitats, i.e. seagrass Posidonia oceanica meadows, coralligenous formations, and marine caves, were determined through a systematic planning approach. Available information on the distribution of these habitats across the entire Mediterranean Sea was compiled to produce basin-scale distribution maps. Conservation targets for each habitat type were set according to European Union guidelines. Surrogates were used to estimate the spatial variation of opportunity cost for commercial, non-commercial fishing, and aquaculture. Marxan conservation planning software was used to evaluate the comparative utility of two planning scenarios: (a) a whole-basin scenario, referring to selection of priority areas across the whole Mediterranean Sea, and (b) an ecoregional scenario, in which priority areas were selected within eight predefined ecoregions. Although both scenarios required approximately the same total area to be protected in order to achieve conservation targets, the opportunity cost differed between them. The whole-basin scenario yielded a lower opportunity cost, but the Alboran Sea ecoregion was not represented and priority areas were predominantly located in the Ionian, Aegean, and Adriatic Seas. In comparison, the ecoregional scenario resulted in a higher representation of ecoregions and a more even distribution of priority areas, albeit with a higher opportunity cost. We suggest that planning at the ecoregional level ensures better representativeness of the selected conservation features and adequate protection of species, functional, and genetic diversity across the basin. While there are several initiatives that identify priority areas in the Mediterranean Sea, our approach is novel as it combines three issues: (a) it is based on the distribution of habitats and not species, which was rarely the case in previous efforts, (b) it considers spatial variability of cost throughout this socioeconomically heterogeneous basin, and (c) it adopts ecoregions as the most appropriate level for large-scale planning.

Pendant bioconstructions cemented by microbial carbonate in submerged marine caves (Holocene, SE Sicily)

Unusual pendant bioconstructions occur within two submerged caves in the Plemmirio Marine Protected Area, south of Syracuse (SE Sicily). These cm- to dm-sized bioconstructions project downward from the cave roofs. The main framework builders are serpulids belonging to the genera Protula, Semivermilia and Josephella. Encrusting bryozoans, corals, hydrozoans and sponges are subordinately present, whereas bivalves and brachiopods are overall rare. These faunal associations are characteristic of the studied caves, but only in some places they form small bioconstructions that are cemented by microbial carbonates made up by autochthonous, peloidal to clotted peloidal and aphanitic micrite. The autochthonous micrite stabilizes the pendant bioconstructions, herein referred to as biostalactites. The microbial carbonate reveals high contents of bacterial lipid biomarkers. Among the most abundant compounds are mono-O-alkyl glycerol ethers (MAGEs) and branched fatty acids (10-Me-C16:0; iso- and anteiso-C15:0 and -C17:0), interpreted as biomarkers of sulfate-reducing bacteria. Other compounds preserved in the autochthonous carbonates include lipids derived from marine zoo- and phytoplankton (brassicasterol, dinosterol and monounsaturated short-chain fatty acids), unspecified marine bacteria (saturated and monounsaturated short-chain fatty acids) and land plants (long-chain fatty acids, long-chain alcohols, stigmasterol, sitosterol and campesterol). The observed lipid biomarker signatures are remarkably similar to those of post-glacial reefal microbialites, where microbialite formation in cavities of the coral framework was also mediated by sulfate-reducing bacteria. In the submerged caves of Plemmirio Marine Protected Area, serpulid colonies apparently occur preferentially where freshwater is seeping through crevices in the limestone. The consequent nutrification is believed to favor serpulid aggregation and the growth of other skeletal (i.e., bryozoans and corals) and soft-bodied organisms (i.e., sponges and ascidiae). The resultant accumulation of biomass and its taphonomy provide niches for sulfate-reducing bacteria, which induce carbonate precipitation cementing and stabilizing the biostalactites. The finding of pendant, cemented bioconstructions in the Mazzere and Granchi caves of the Plemmirio Marine Protected Area reveals that sulfate-reducing bacteria are involved in microbialite formation in various cryptic environments. The formation of such peloidal to clotted peloidal microcrystalline carbonates in cryptic ecosystems is a significant factor for the stabilization of different kinds of bioconstructions, spanning from small biostalactites to large reefs.

Three-dimensional mapping of marine caves using a handheld echosounder

Three-dimensional mapping of marine caves using a handheld echosounder

Evolution of cave Axiokebuita and Speleobregma (Scalibregmatidae, Annelida)

The evolutionary history of Axiokebuita and Speleobregma, two poorly known lineages of annelids exclusive from deep‐sea or marine caves but always from crevicular habitats, is explored here. Speleobregma lanzaroteum Bertelsen, 1986, and Axiokebuita cavernicola sp. n. are described from anchialine and marine caves of the Canary Islands using light and electron microscopy. Speleobregma lanzaroteum is previously known only from a single specimen from the water column of an anchialine cave in Lanzarote. Emended diagnosis, details on the ciliary patterns and behavioural observations are provided based on newly collected material and in situ observations. Axiokebuita cavernicola sp. n. is found in Pleistocene gravel deposits in a shallow water marine cave in Tenerife (Canary Islands). The new species is characterized by the presence of dorsal ciliary bands and short knob‐like neuropodial cirri from segment two. The porosity and permeability of the gravelly environment of A. cavernicola sp. n. are shown to be equivalent to the water column or crevices of Speleobregma and other Axiokebuita spp. Phylogenetic analyses of five gene fragments and 44 terminals using maximum‐likelihood and Bayesian methods support a derived position of A. cavernicola sp. n. within Axiokebuita and confirm a sister‐group relationship of Axiokebuita with Speleobregma with high nodal support. The Axiokebuita–Speleobregma clade is morphologically characterized by a globular pygidium with adhesive glands and ventral ungrooved ciliated palps. Our results support two independent cave colonization events, favoured by the preadaptation of the members of Axiokebuita–Speleobregma lineage to crevicular habitats.

Soft-bottom diversity patterns in marine caves; Lessons from crustacean community

Previous marine cave studies have been generally qualitative, focusing on hard benthic communities of single caves. The ecological patterns of marine cave assemblages, particularly those with soft-sediment bottoms, are poorly known. The aim of this study was to investigate ecological patterns of macroinfauna inhabiting marine caves. Using a multifactorial design, the soft-bottom crustacean fauna of six previously unsampled Mediterranean marine caves was studied. To investigate the influence of the marine cave habitat on local crustacean assemblage two stations were compared in each cave; one internal site from within the marine cave cavity and one external site, in sediments near the opening of the cave. The caves selected had a wide range of profundity in order to explore the influence of depth on the community. External sediments had higher species richness, and a significant decline in diversity values inside the caves was found at all marine cave locations studied. The abundance of organisms was strongly influenced by depth, with deeper internal cave sites having lower abundance than the external stations, while more shallow internal cave sites provide a more stable environment, which allows higher density of individuals. The results described here for soft-sediment marine cave bottoms are in contrast to previous observations in hard benthic marine cave communities, where small-scale variability was similar for interior and exterior cave habitats. The results of this study show that even in the absence of endemic cave taxa, the species assemblage at each cave was clearly different from that present in the exterior habitat and also from that present in other cave sediments. This high variability and strong individuality observed in soft-bottom marine caves suggest that there are many and complex factors controlling these communities.

Meiobenthic copepod fauna of a marine cave (NW Mediterranean) closely resembles that of deep-sea communities

The 3PP marine cave near Marseille (NW Mediterranean) is at a depth of only 15 m. Nevertheless, the cave is a unique deep-sea-like habitat zone due to total darkness, lack of water circulation, oligotrophy, and cold homothermy, a thermal regime similar to that of the deep Mediterranean. We studied the meiofaunal community composition and diversity at 3 sampling stations in the cave (entrance, middle, and blind end). Major taxon composition, based on presence/absence data, did not vary over the transect; however, significant differences in community were found. Tardigrades were the only major taxon restricted to the inner parts of the cave. Copepod diversity decreased towards the inner parts of the cave. The 3PP Cave was characterized by very low abundances of meiofaunal organisms similar to abyssal sites elsewhere. A total of 405 individual copepods were assigned to 27 families and 90 species (75% of them new to science). Significant differences in copepod communities between stations were found at family, genus, and species level. Some harpacticoid taxa generally known from the deep sea, such as Marsteinia, Ancorabolina, Paranannopus, Nematovorax, and Argestidae, were represented in the 3PP Cave. A naive Bayes model was used for the first time to classify the communities as 'shallow' or 'abyssal'. The meiobenthic communities at the entrance and the end of the cave were unequi vocally classified as 'shallow' and 'abyssal' respectively, while the middle part of the cave presented a mixed community. Our study further highlights the strong faunal and community affinities between marine caves and the deep sea, indicating the existence of dispersal mechanisms from deep waters into the euphotic zone for benthic organisms.

An overview of the Mediterranean cave-dwelling horny sponges (Porifera, Demospongiae)

The present synthesis focuses on the so called ‘horny sponges’ recorded from marine caves of the Mediterranean Sea. The main aim is to provide a list of all recorded species, diagnostic keys to their identification up to family and genus level, and exhaustive, formally uniform descriptions at the species level contributing to sharing of information on the faunistics and taxonomy of Mediterranean cave-dwelling species, including habitat preferences. The majority of species was recorded in 105 Mediterranean marine caves hosting four orders of horny sponges belonging to 9 families, 19 genera and 40 species. Species endemic to the Mediterranean Sea harboured in marine caves are 14 with an endemicity value of 35%. For each species morphological descriptions are supported by illustrations both original and from the literature, including the diagnostic traits of the skeleton by light and scanning electron microscopy giving further characterization at the specific level. A detailed map together with a list of all caves harbouring horny sponges is also provided with geographic coordinates.

Facilitation of coral reef biodiversity and health by cave sponge communities

Marine caves are understudied ecosystems that are frequently associated with coral reef communities; many are tidally influenced and may host a highly diverse sponge fauna. Although each cave represents a distinct habitat likely structured by site-specific hydrographic processes, a more complete understanding of the ecology of these communities requires com parative studies. Based on a gradient of sponge cover within 5 Bahamian caves, we conducted a natural experiment in sponge-derived nutrient enrichment of nearby patch reefs. We tested the hypothesis that water exiting the cave during low tide provides a nutrient-rich resource that facilitates the diversity and health of nearby reef communities. The percent cover and diversity of corals surrounding the openings of caves were significantly higher than in similar habitats farther removed from these communities. There was a significant correlation between percent sponge cover within the caves and nitrate concentrations in seawater flowing out of the caves, and δ15N stable isotope signatures indicated enrichment of the nearby reefs by sponge-derived nitrate. Zooxanthellae abundance and total protein concentration were higher in corals from reefs near cave entrances, suggesting that those corals benefited more from cave nutrients than did corals farther from cave openings. In addition to corals, percent algal cover increased near cave entrances, but these potential competitors of corals were kept in check by increased levels of herbivory relative to sites removed from cave mouths. As global environmental changes continue to impact coral reef ecosystems, diversity ‘hot spots’, such as these marine caves, could serve as refuges and ‘seedbanks’ for nearby dwindling reef habitats.

Feeding habits of amphipods (Crustacea: Malacostraca) from shallow soft bottom communities: Comparison between marine caves and open habitats

Marine caves are environments of great interest since the organisms that inhabit them are forced to develop specific adaptations to high constraint conditions. Because of some of these particular conditions, such as light absence or oligotrophy, it can be expected that feeding strategies into caves differ from that present outside them. Nevertheless, no studies have been done to compare the trophic structure of marine caves and open habitats, at least for amphipod communities, considering their importance both inside and outside of the caves. In this study, the diet of the dominant amphipod species living on shallow sediments, both inside and outside of six marine caves in western Mediterranean, was characterized. Thereby, the gut content of 17 amphipod species was studied, being this study the first attempt to establish the feeding habit of most of these species. Analysis of digestive contents of the species showed that amphipod diet is less diverse in sediments than in other environments, such as algae and seagrasses. No herbivorous species were found in the sediment and carnivorous amphipods showed a little variety of prey, feeding mainly on crustaceans. Differences in the trophic structure were also found between marine caves and open habitats sediments: while outside the caves detritivorous was the dominant group (both in number of species and number of individuals), amphipods mainly play the role of carnivorous inside the caves. No detritivorous species were found into the caves, where carnivorous represents almost 60% of amphipods species and more than 80% of amphipod individuals. This pattern obtained in amphipods differ from the general trend observed in marine cave organisms, for which a generalist diet, such as omnivory, usually is an advantage in these oligotrophic conditions. The possible causes of this pattern are discussed.

Mysids associated with sea anemones from the tropical Atlantic: descriptions of Ischiomysis new genus, and two new species in this taxon (Mysida, Mysidae, Heteromysinae)

The males of Ischiomysis gen. nov. are unique among the currently known genera of the order Mysida by peculiar modifications of the ischium and praeischium of the eighth thoracic endopod. The type species, I. telmatactiphila sp. nov., forms compact aggregations above the oral disc of the club-tipped sea anemone Telmatactis cricoides from the island of São Tomé in the Gulf of Guinea. Less compact aggregations are formed by I. peterwirtzi sp. nov. from the island of São Vicente in the Cape Verde archipelago. Such looser aggregations were found in marine (micro)caves, wherein they extended over the anemones and adjacent rock recesses. An undetermined, visually similar mysid with similar distribution above the oral disc is documented by a colour photograph from Trindade, a small oceanic island in the tropical south-west Atlantic. Potential morphological relationships between the new genus and certain species of Heteromysis from the Caribbean and the Indian Ocean are discussed.

Markers of MIS 5 sea level fluctuations in the Bergeggi Marine Cave (NW Mediterranean Sea)

REGIONAL SETTING The onshore territory of the Liguria region (Fig.1) is represented by an arch-shaped mountain ridge, presenting a steep seaward slope and with its watershed very close to the Mediterranean sea. From a geological point of view, the region can be divided into two parts. The western part of the arch (west of Genova), NE–SW oriented, is considered to be the southern continuation of the Western Alps (Ligurian Alps, Vanossi et al., 1994. In this part, Provencal, Flysch, SubBrianconneese, Brianconneese, Piedmonteese, and metaophiolitic units and related metamorphic covers outcrop. West of Genova (Fig.2) an ophiolitic complex (named the Voltri Group) marks the transition between the Alpine and the Apenninic domains (Cortesogno & Haccard, 1984) (the latter stretching NW–SE), where Ligurian, SubLigurian and Tuscan units outcrop (Gianmarino et al., 2002). Fig.1 Geographical position of the Liguria Region in the Italian peninsula

Marine caves of the Mediterranean Sea: a sponge biodiversity reservoir within a biodiversity hotspot.

Marine caves are widely acknowledged for their unique biodiversity and constitute a typical feature of the Mediterranean coastline. Herein an attempt was made to evaluate the ecological significance of this particular ecosystem in the Mediterranean Sea, which is considered a biodiversity hotspot. This was accomplished by using Porifera, which dominate the rocky sublittoral substrata, as a reference group in a meta-analytical approach, combining primary research data from the Aegean Sea (eastern Mediterranean) with data derived from the literature. In total 311 species from all poriferan classes were recorded, representing 45.7% of the Mediterranean Porifera. Demospongiae and Homoscleromorpha are highly represented in marine caves at the family (88%), generic (70%), and species level (47.5%), the latter being the most favored group along with Dictyoceratida and Lithistida. Several rare and cave-exclusive species were reported from only one or few caves, indicating the fragmentation and peculiarity of this unique ecosystem. Species richness and phylogenetic diversity varied among Mediterranean areas; the former was positively correlated with research effort, being higher in the northern Mediterranean, while the latter was generally higher in caves than in the overall sponge assemblages of each area. Resemblance analysis among areas revealed that cavernicolous sponge assemblages followed a pattern quite similar to that of the overall Mediterranean assemblages. The same pattern was exhibited by the zoogeographic affinities of cave sponges: species with Atlanto-Mediterranean distribution and Mediterranean endemics prevailed (more than 40% each), 70% of them having warm-water affinities, since most caves were studied in shallow waters. According to our findings, Mediterranean marine caves appear to be important sponge biodiversity reservoirs of high representativeness and great scientific interest, deserving further detailed study and protection.

Floristic macroalgal diversity in selected submarine caves located within two marine protected areas off Lampedusa Island and Sicily (Italy)

Abstract We investigated phytobenthos in submerged marine caves. Underwater caves have rarely been examined for floristic composition. The study was carried out in two Mediterranean marine protected areas (MPAs) [Plemmirio (Maddalena Peninsula, Syracuse, Ionian Sea) and Pelagean Islands (Straits of Sicily)] and the caves were chosen on the basis of their geomorphology, exposure, and bathymetry. From our comparative study of cave floras, we demonstrated that the macroalgal flora of each cave is influenced by the floristic composition of the adjacent area that is a natural source of recruits and by the light environment. Caves that are “visited” (i.e., those situated on one of the underwater routes for scuba divers visiting the MPAs) had floristic richnesses higher than those of “scarcely” or “not visited” ones (i.e., not on tourist routed). This is likely because the visited caves, due to their large entrance and shallow location, have good lighting that favors high macroalgal biodiversity.

Increasing heterogeneity of sensitive assemblages as a consequence of human impact in submarine caves

Submarine caves are considered as a top priority for conservation, but the effects of common pressures are poorly known for these habitats. Here, we examined the effect of recreational human visitation on a selection of submarine caves in a Mediterranean Marine Protected Area (40°35′40″N; 8°11′39″E) where diving activities are regulated. Sampling was conducted in visited and not visited caves to assess whether diving activities have a significant effect on cave habitats, what are the components of biodiversity most affected by this disturbance, and its potential effects on spatial heterogeneity of benthic assemblages. Results clearly showed that human visitation could significantly affect spatial patterns of benthic assemblages. Organisms with erect growth forms were significantly more abundant and homogeneously distributed where diving activities are forbidden. An increase in the small-scale heterogeneity of assemblages and a decrease in their three-dimensional structure could be the ultimate consequences of human visitation. The interaction between specific stressors and the patterns of distribution of species and assemblages can drive their spatial heterogeneity also in unique habitats like marine caves, representing an early warning for the development of appropriate management measures.

Soft-bottom crustacean assemblages in Mediterranean marine caves: the cave of Cerro Gordo (Granada, Spain) as case study

Although marine caves are priority conservation areas according to the Directive 92/43/CEE of the European Community, there is a lack of studies dealing with their soft-bottom communities. For a case study, we selected the Cerro Gordo cave at 15 m depth. Three different zones were defined: a semi-dark 25-m long entrance area, a dark intermediate area of 35 m, and the final zone at 90 m from the entrance. Sediment samples were taken from these zones as well as from outside the cave (control) by SCUBA diving. Six rectangular cores of 10 × 250 cm2 were collected in each site for macrofaunal study, and three more replicates were taken to analyze physico-chemical parameters. The granulometry showed a clear gradient from medium sands outside the cave to silt and clay in the inner zone. Measurements of the crustacean assemblages showed that the number of species and abundance were significantly higher outside the cave (30–40 species, >4,000 ind m−2) than inside (5–10 species, <1,000 ind m−2). Multivariate analyses showed a clear difference in species composition between outside and inside the cave. Caprellids, tanaids, cumaceans, and decapods were only found outside the cave, while gammarids and isopods were present both outside and inside the cave. The gammarid Siphonoecetes sabatieri and the tanaid Apseudes latreilli were the dominant species outside the cave, while the gammarids Harpinia pectinata, Harpinia crenulata, and Harpinia ala were dominant inside. The present study represents an increase in depth range and geographic distribution for Kupellonura mediterranea and Monoculodes packardi. This is the first description of soft-bottom crustacean communities from submarine caves of southern Spain.