Shedding light on the Ophel biome: the trans-Tethyan phylogeography of the sulfide shrimp Tethysbaena (Peracarida: Thermosbaenacea) in the Levant.

Background: Tethysbaena are small peracarid crustaceans inhabiting extreme environments such as subterranean lakes and thermal springs, represented by endemic species found around the ancient Tethys, including the Mediterranean, Arabian Sea, Mid-East Atlantic, and the Caribbean Sea. Two Tethysbaena species are known from the Levant: T. relicta, found along the Dead Sea-Jordan Rift Valley, and T. ophelicola, found in the Ayyalon cave complex in the Israeli coastal plain, both belonging to the same species-group based on morphological cladistics. Along the biospeleological research of the Levantine subterranean fauna, three biogeographic hypotheses determining their origins were proposed: (1) Pliocenic transgression, (2) Mid-late Miocenic transgression, and (3) The Ophel Paradigm, according to which these are inhabitants of a chemosynthetic biome as old as the Cambrian. Methods: Tethysbaena specimens of the two Levantine species were collected from subterranean groundwaters. We used the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear ribosomal 28S (28S rRNA) gene to establish the phylogeny of the Levantine Tethysbaena species, and applied a molecular clock approach for inferring their divergence times. Results: Contrary to the morphological cladistic-based classification, we found that T. relicta shares an ancestor with Tethysbaena species from Oman and the Dominican Republic, whereas the circum-Mediterranean species (including T. ophelicola) share another ancestor. The mean age of the node linking T. relicta from the Dead Sea-Jordan Rift Valley and Tethysbaena from Oman was 20.13 MYA. The mean estimate for the divergence of T. ophelicola from the Mediterranean Tethysbaena clade dated to 9.46 MYA. Conclusions: Our results indicate a two-stage colonization of Tethysbaena in the Levant: a late Oligocene transgression, through a marine gulf extending from the Arabian Sea, leading to the colonization of T. relicta in the Dead Sea-Jordan Rift Valley, whereas T. ophelicola, originating from the Mesogean ancestor, inhabited anchialine caves in the coastal plain of Israel during the Mid-Miocene.

Flatfoot in Africa, the cirripede Chthamalus in the west Indian Ocean.

Barnacles of the genus Chthamalus are commonly encountered rocky intertidal shores. The phylogeography of the different species in the Western Indian Ocean is unclear. Using morphological characteristics as well as the molecular markers mitochondrial cytochrome oxygenase subunit I (COI) and the nuclear sodium-potassium ATPase (NaKA), we identified four clades representing four species in the Western Indian Ocean and its adjacent seas. Among these species, a newly identified species, Chthamalus barilani, which was found in Madagascar, Zanzibar and Tanzania. Chthamalus from the coasts of Tanzania and Zanzibar is identified morphologically as C. malayensis, and clusters with C. malayensis from the Western Pacific and the Indo Malayan regions. C. malayensis is regarded as a group of four genetically differentiated clades representing four cryptic species. The newly identified African clade is genetically different from these clades and the pairwise distances between them justify the conclusion that it is an additional cryptic species of C. malayensis. This type of genetic analyses offers an advantage over morphological characterization and allowed us to reveal that another species, C. barnesi, which is known from the Red Sea, is also distributed in the Arabian Sea and the Persian Gulf. We could also confirm the presence of the South African species C. dentatus in the Mozambique channel. This represents the Northeastern limit of C. dentatus, which is usually distributed along the coast of southern Africa up to the Islands of Cape Verde in West Africa. Altogether, based on a combination of morphology and genetics, we distinct between four clusters of Chthamalus, and designate their distribution in the West Indian Ocean. These distinctions do not agree with the traditional four groups reported previously based merely on morphological data. Furthermore, these findings underline the importance of a combining morphological and genetics tools for constructing barnacle taxonomy.

A star is torn-molecular analysis divides the Mediterranean population of Poli's stellate barnacle, Chthamalus stellatus (Cirripedia, Chtamalidae).

Poli's stellate barnacle, Chthamalus stellatus Poli, populates the Mediterranean Sea, the North-Eastern Atlantic coasts, and the offshore Eastern Atlantic islands. Previous studies have found apparent genetic differences between the Atlantic and the Mediterranean populations of C. stellatus, suggesting possible geological and oceanographic explanations for these differences. We have studied the genetic diversity of 14 populations spanning from the Eastern Atlantic to the Eastern Mediterranean, using two nuclear genes sequences revealing a total of 63 polymorphic sites. Both genotype-based, haplotype-based and the novel SNP distribution population-based methods have found that these populations represent a geographic cline along the west to east localities. The differences in SNP distribution among populations further separates a major western cluster into two smaller clusters, the Eastern Atlantic and the Western Mediterranean. It also separates the major eastern cluster into two smaller clusters, the Mid-Mediterranean and Eastern Mediterranean. We suggested here environmental conditions like surface currents, water salinity and temperature as probable factors that have formed the population structure. We demonstrate that C. stellatus is a suitable model organism for studying how geological events and hydrographic conditions shape the fauna in the Mediterranean Sea.

A new species of the coral associated barnacle (Thoracica: Pyrgomatidae: Pyrgoma) from a deep-sea oculinid coral in New Caledonian waters.

The present study describes a new species of Pyrgoma Leach, 1817, a coral associated barnacle attached to Tubastrea, from the south of New Caledonia. Pyrgoma spurtruncata sp. nov. is morphologically close to P. cancellatum Leach, 1818, P. japonica Weltner, 1897 and P. kuri Hoek, 1913 in the absence of extended tergal muscle crests. Pyrgoma cancellatum and P. kuri have a shallow, fully open, medial furrow of the tergal spur, whereas in P. spurtruncata sp. nov. the medial furrow is deeper and closed. Pyrgoma spurtruncata sp. nov. differs from P. japonica Weltner, 1897 in the width of the tergal spur and the length of the rostral tooth of the scutum. Phylogenetic analyses based on two mitochondrial markers, 12S rDNA and COI, confirm a unique, distinct clade of P. spurtruncata sp. nov. among the current available molecular information regarding Pyrgoma species.

Multiple transgressions and slow evolution shape the phylogeographic pattern of the blind cave-dwelling shrimp Typhlocaris.

BACKGROUND: Aquatic subterranean species often exhibit disjunct distributions, with high level of endemism and small range, shaped by vicariance, limited dispersal, and evolutionary rates. We studied the disjunct biogeographic patterns of an endangered blind cave shrimp, Typhlocaris, and identified the geological and evolutionary processes that have shaped its divergence pattern. METHODS: We collected Typlocaris specimens of three species (T. galilea, T. ayyaloni, and T. salentina), originating from subterranean groundwater caves by the Mediterranean Sea, and used three mitochondrial genes (12S, 16S, cytochrome oxygnese subunit 1 (COI)) and four nuclear genes (18S, 28S, internal transcribed spacer, Histon 3) to infer their phylogenetic relationships. Using the radiometric dating of a geological formation (Bira) as a calibration node, we estimated the divergence times of the Typhlocaris species and the molecular evolution rates. RESULTS: The multi-locus ML/Bayesian trees of the concatenated seven gene sequences showed that T. salentina (Italy) and T. ayyaloni (Israel) are sister species, both sister to T. galilea (Israel). The divergence time of T. ayyaloni and T. salentina from T. galilea was 7.0 Ma based on Bira calibration. The divergence time of T. ayyaloni from T. salentina was 5.7 (4.4-6.9) Ma according to COI, and 5.8 (3.5-7.2) Ma according to 16S. The computed interspecific evolutionary rates were 0.0077 substitutions/Myr for COI, and 0.0046 substitutions/Myr for 16S. DISCUSSION: Two consecutive vicariant events have shaped the phylogeographic patterns of Typhlocaris species. First, T. galilea was tectonically isolated from its siblings in the Mediterranean Sea by the arching uplift of the central mountain range of Israel ca. seven Ma. Secondly, T. ayyaloni and T. salentina were stranded and separated by a marine transgression ca. six Ma, occurring just before the Messinian Salinity Crisis. Our estimated molecular evolution rates were in one order of magnitude lower than the rates of closely related crustaceans, as well as of other stygobiont species. We suggest that this slow evolution reflects the ecological conditions prevailing in the highly isolated subterranean water bodies inhabited by Typhlocaris.

Description of five new coral associated Barnacles of the genus Trevathana (Balanomorpha: Pyrgomatidae) in Pacific Waters.

Five new species of coral inhabiting barnacles of the genus Trevathana (Balanomorpha: Pyrgomatidae), T. dongshaensis sp. nov., T. conica sp. nov., T. doni sp. nov., T. longidonta sp. nov. and T. taiwanus sp. nov., are described. These species are found in West Pacific waters including Japan, Taiwan (mainland and adjacent outlying islands including Dongsha Atoll) and Papua New Guinea. The species exhibit morphological differences in the scutum, the tergum, and cirri II and III, and form distinct clades in a phylogenetic tree based on DNA sequences of two genes, 12S rDNA and cytochrome C oxidase subunit I. Three of the five species, T. dongshaensis sp. nov., T. conica sp. nov. and T. taiwanus sp. nov., have relatively narrow distribution ranges and were recorded from the Dongsha Atoll (T. dongshaensis sp. nov. and T. conica sp. nov.) and the Taiwanese mainland (T. taiwanus sp. nov.). Trevathana longidonta sp. nov. and T. doni sp. nov. have wider distributions. Trevathana longidonta sp. nov. was collected from Japan, Taiwan and Dongsha Atoll and T. doni sp. nov. was collected from Taiwan, Dongsha Atoll and Papua New Guinea. In the waters of Japan, Taiwan and Dongsha Atoll, all the recorded Trevathana species inhabit corals of the family Merulinidae. However, in Papua New Guinea, T. doni sp. nov. is also recorded in the coral Oxypora, belonging to the family Lobophylliidae, and individuals living on Lobophyllidae and Merulinidae did not exhibit great variation in the divergence of the COI and 12S genes.

Phylogeography on the rocks: The contribution of current and historical factors in shaping the genetic structure of Chthamalus montagui (Crustacea, Cirripedia).

The model marine broadcast-spawner barnacle Chthamalus montagui was investigated to understand its genetic structure and quantify levels of population divergence, and to make inference on historical demography in terms of time of divergence and changes in population size. We collected specimens from rocky shores of the north-east Atlantic Ocean (4 locations), Mediterranean Sea (8) and Black Sea (1). The 312 sequences 537 bp) of the mitochondrial cytochrome c oxidase I allowed to detect 130 haplotypes. High within-location genetic variability was recorded, with haplotype diversity ranging between h = 0.750 and 0.967. Parameters of genetic divergence, haplotype network and Bayesian assignment analysis were consistent in rejecting the hypothesis of panmixia. C. montagui is genetically structured in three geographically discrete populations, which corresponded to north-eastern Atlantic Ocean, western-central Mediterranean Sea, and Aegean Sea-Black Sea. These populations are separated by two main effective barriers to gene flow located at the Almeria-Oran Front and in correspondence of the Cyclades Islands. According to the 'isolation with migration' model, adjacent population pairs diverged during the early to middle Pleistocene transition, a period in which geological events provoked significant changes in the structure and composition of palaeocommunities. Mismatch distributions, neutrality tests and Bayesian skyline plots showed past population expansions, which started approximately in the Mindel-Riss interglacial, in which ecological conditions were favourable for temperate species and calcium-uptaking marine organisms.

Boxer crabs induce asexual reproduction of their associated sea anemones by splitting and intraspecific theft.

Crabs of the genus Lybia have the remarkable habit of holding a sea anemone in each of their claws. This partnership appears to be obligate, at least on the part of the crab. The present study focuses on Lybia leptochelis from the Red Sea holding anemones of the genus Alicia (family Aliciidae). These anemones have not been found free living, only in association with L. leptochelis. In an attempt to understand how the crabs acquire them, we conducted a series of behavioral experiments and molecular analyses. Laboratory observations showed that the removal of one anemone from a crab induces a "splitting" behavior, whereby the crab tears the remaining anemone into two similar parts, resulting in a complete anemone in each claw after regeneration. Furthermore, when two crabs, one holding anemones and one lacking them, are confronted, the crabs fight, almost always leading to the "theft" of a complete anemone or anemone fragment by the crab without them. Following this, crabs "split" their lone anemone into two. Individuals of Alicia sp. removed from freshly collected L. leptochelis were used for DNA analysis. By employing AFLP (Fluorescence Amplified Fragments Length Polymorphism) it was shown that each pair of anemones from a given crab is genetically identical. Furthermore, there is genetic identity between most pairs of anemone held by different crabs, with the others showing slight genetic differences. This is a unique case in which one animal induces asexual reproduction of another, consequently also affecting its genetic diversity.

Revision of the coral-inhabiting genus Conopea (Cirripedia: Archaeobalanidae) with description of two new species of the genera Conopea and Acasta.

The morphology of archaeobalanid barnacles of the genera Conopea and Acasta inhabiting cnidarians of the orders Alcyonacea and Antipatharia was surveyed. Based on morphological characteristics, it became evident that the species of the nominal genus Conopea fell into three natural groups affiliated to three archaeobalanid genera, Conopea s.s., Acasta and Solidobalanus. The relationships between the species of Conopea s.l. and those of Acasta inhabiting alcyanaceans are analyzed using a cladistic approach. The barnacles of the genus Conopea s.s. are characterized by a strong, firm shell; the orifice is not dentate; rostral and sometimes carinal plates are often elongated in their basal parts; the rostro-carinal axis of the basis is often elongated and clasps the axis of the host coral; the radii have summits parallel to the basal margin of the parietes, and denticulated sutural margins; the scutum has simple growth ridges without longitudinal striation or ribs; the basitergal angle is truncated (sinusoid); and the basidorsal point of the penis is developed. The genus Conopea s.s. encompasses 20 epizoic species from tropical and temperate seas, inhabiting alcyonaceans (sea fans or gorgonians) and antipatharians. A new species of Conopea and a new species of Acasta are described, and a key to the species of Conopea s.s. is provided.

Mitochondrial genome of the intertidal acorn barnacle Tetraclita serrata Darwin, 1854 (Crustacea: Sessilia): Gene order comparison and phylogenetic consideration within Sessilia.

The complete mitochondrial genome of the intertidal barnacle Tetraclita serrata Darwin, 1854 (Crustacea: Maxillopoda: Sessilia) is presented. The genome is a circular molecule of 15,200 bp, which encodes 13 PCGs, 2 ribosomal RNA genes, and 22 transfer RNA genes. All non-coding regions are 591 bp in length, with the longest one speculated as the control region (389 bp), which is located between srRNA and trnK. The overall A+T content of the mitochondrial genome of T. serrata is 65.4%, which is lowest among all the eight mitochondrial genomes reported from sessile barnacles. There are variations of initiation and stop codons in the reported sessile barnacle mitochondrial genomes. Large-scale gene rearrangements are found in these genomes as compared to the pancrustacean ground pattern. ML and Bayesian analyses of all 15 complete mitochondrial genomes available from Maxillopoda lead to identical phylogenies. The phylogenetic tree based on mitochondrial PCGs shows that Argulus americanus (Branchiura) cluster with Armillifer armillatus (Pentastomida), distinct from all ten species from Cirripedia. Within the order Sessilia, Amphibalanus amphitrite (Balanidae) clusters with Striatobalanus amaryllis (Archaeobalanidae), and Nobia grandis (Pyrgomatidae). However, the two Megabalanus (Balanidae) are separated from the above grouping, resulting in non-monophyly of the family Balanidae. Moreover, the two Megabalanus have large-scale rearrangements as compared to the gene order shared by former three species. Therefore, both phylogenetic analysis using PCG sequences and gene order comparison suggest that Balanidae is not a monophyletic group. Given the limited taxa and moderate support values of the internal branches, the non-monophyly of the family Balanidae requires further verification.