Display omitted
•Mitogenomes of two new metacrangonyctidae species were sequenced.•Metacrangonyx dhofarensis from Oman inhabits the easternmost part of Tethys seashore.•M. dhofarensis lineage ...represents the earliest split of phylogeny about 126 Myr ago.•Narrow geographic distributions are found for clades, except for the island one.•Opening of ancient Tethys sea drove diversification by vicariance.
The Metacrangonyctidae are a small family of amphipod crustaceans of marine origin found only in subterranean continental waters. They display a broad but punctuated distribution between the Caribbean and the Arabian Peninsula, with major disjunctions either due to vicariance by plate tectonics or to occurrence of recent episodes of long-distance transoceanic dispersal. We re-examine the phylogeny of the family and the time frame for its diversification using mitochondrial genomes in the light of two key taxa recently discovered, from Oman (Arabian Peninsula) and the Rif area of Morocco, respectively. We also use a novel fossil calibration scheme of the mitogenome phylogeny. Results of previous analyses based on palaeogeographic calibrations are not contradicted by the new approach, with vicariance by plate tectonics remaining as the main explanatory factor for the amphi-Atlantic distribution displayed by this ancient group of subterranean amphipods.
A survey of biogenic coralline sands in the littoral fringe of a tropical island in Japan brought a new amphipod species to light. This species represents the first record of the subterranean genus ...Metaniphargus from the West Pacific. The majority of the species in this genus occur in the Caribbean, but a report from Hawaii and now from Japan defies the endemic Caribbean status it kept for so long. Metaniphargus shiroi sp. nov. is described, and morphological comparisons are made with closely resembling species from Hawaii and the Cayman Islands (genus Metaniphargus), and the Great Barrier Reef and California (genus Dulzura). Involvement of non-congeners in the comparisons is necessary as character overlap is abundant. These comparisons suggest that the presence of form-related body types in the shallow marine interstitial realm is circumtropical and follows habitat suitability rather than sudden dispersal or vicariance events.
Semi-terrestrial talitrid amphipods of the genus
Cryptorchestia
(sensu Lowry and Fanini 2013) associated with freshwater-soaked leaf litter were known to occur in inland lakes of Turkey and at the ...shores of the Black Sea. Before 2013 they had been reported as
Orchestiacavimana
and later as
Cryptorchestiacavimana
. In our phylogenetic tree, inferred from a mitochondrial and nuclear gene dataset (cytochrome oxidase I (COI), and histone H3 (H3), respectively), we show that these Turkish populations belong to
Cryptochestiagarbinii
, a common and widespread continental species, which is closely related to
C.cavimana
(endemic to Cyprus) and
C.ruffoi
(endemic to Rhodes). For the Turkish and European populations of
C.garbinii
, we found low levels of both genetic differentiation and morphological variation, and an age-related size variability (increasing at each moult) of the small lobe in the male gnathopod I merus, the main taxonomically diagnostic character for
Cryptorchestia
. A mainland (
C.garbinii
) versus insular isolation and in situ speciation (
C.cavimana
, and
C.ruffoi
) in the two east Mediterranean islands of Cyprus and Rhodes is discussed in relation to terrestrial
Cryptorchestia
species endemic to North East Atlantic volcanic islands (Azores, Canary Islands, and Madeira). The incorporation of five Mediterranean and Atlantic
Orchestia
species in the Bayesian analysis of the two genes (COI, and H3) indicated that both genera
Orchestia
and
Cryptorchestia
are not monophyletic.
(2007). b The Dutch Caribbean composed of the Leeward Islands (Aruba, Curaçao, and Bonaire) in the Southern Caribbean and the Windward Islands (Saba, St. Eustatius, and St. Maarten) with Saba Bank in ...the Eastern Caribbean Although the Caribbean has less species than the Indo-Pacific, this does not imply that the marine fauna and flora of the Caribbean are sufficiently well known or that there is little need for additional biodiversity research on Caribbean reefs. Many marine exotic species in the Caribbean can easily be overlooked because they usually consist of invertebrates and algae that are not easily recognized (Debrot et al. 2011) and, therefore, they are usually discovered when they become invasive and their populations reach outbreak proportions. Because of such harmful species introductions and possible local species extinctions on Caribbean coral reefs (e.g., Carpenter et al. 2008), there is a need for baseline surveys of local reef biota with specimen sampling and follow-up monitoring in order to be able to accurately notice when species arrive or disappear (Hoeksema et al. 2011; Rocha et al. 2014; Sampey and Marsh 2015; Ballard et al. 2016). Caribbean coral reefs also deserve biodiversity research attention because not all of their species have been reported yet, and these species are likely to participate in hitherto unknown interspecific associations (e.g., Thomas and Klebba 2007; Snijders and Fransen 2010; Ivanenko et al. 2017; Montano et al. 2017b) or appear to have incomplete geographical and bathymetrical distribution range information involving new records for the Atlantic (e.g., Montano et al. 2017a; Van der Loos and Prud’homme van Reine 2017). Together with St. Maarten and Saba, it belongs to the windward islands in the eastern Caribbean, which also includes the submerged Saba Bank, while Aruba, Curaçao, and Bonaire belong to the Leeward Islands in the southern Caribbean (Fig. 1b).
A new species of marine interstitial wormshrimp, Ingolfiella maldivensis , is described from coral sand on the inner and outer reef off Magoodhoo island, Faafu atoll, Maldives. Six females were found ...and compared to other species from the Maldives and those bordering the Indian Ocean and beyond. Morphological resemblance ties it to a species from the Caribbean island of Curaçao. Both species are found in shallow sublittoral interstitial spaces. Keywords: Taxonomy, sublittoral, interstitial habitat, dive sampling, atolls, Indian Ocean
Abstract
While in most species the adult sex ratio is around 1:1, it can be strongly skewed in some species; some of this can be explained by ecological conditions and limits to dispersal. We ...hypothesize that stronger isolation imposed by ecological conditions leads to more pronounced female-biased sex ratios in the groundwater peracarid genus Ingolfiella Hansen, 1903. About 75% of all adults are female, and female-biased sex ratios are present in 30/42 of species for which individuals have been sexed. Sex ratios were not correlated with sexual size dimorphism. The adult sex ratio varied little between species found in different habitats (caves, beach sand, and seabed) thus not supporting our hypothesis that ecological conditions shape adult sex ratios. It appears that sediment structure in most habitats restrict ingolfiellids in their movement. Limited dispersal abilities and small mating assemblages may favour strongly female-biased sex ratios.
Background Both genetic and environmental factors are involved in the etiology of bipolar disorder; however, biological markers for the transmission of the bipolar genotype (“endophenotypes”) have ...not been found. Autoimmune thyroiditis with raised levels of thyroperoxidase antibodies (TPO-Abs) is related to bipolar disorder and may be such an endophenotype. This study was intended to examine whether autoimmune thyroiditis is related to the disease itself, to the (genetic) vulnerability to develop bipolar disorder, or both. Method Blood was collected from 22 monozygotic (MZ) and 29 dizygotic (DZ) bipolar twins and 35 healthy matched control twins to determine TPO-Abs. Results The TPO-Abs were positive in 27% of the bipolar index twins, 29% of the monozygotic bipolar cotwins, 27% of the monozygotic nonbipolar cotwins, 25% of the dizygotic bipolar cotwins, 17% of the dizygotic nonbipolar cotwins, and in 16% of the control twins. Repeated measures analysis of covariance on log-transformed absolute TPO-Abs values revealed significantly increased mean TPO-Abs levels in discordant twin pairs as compared with healthy twin pairs, whereas no difference was found between bipolar patients and their (discordant) nonbipolar cotwins. Conclusions This study shows that autoimmune thyroiditis is related not only to bipolar disorder itself but also to the genetic vulnerability to develop the disorder. Autoimmune thyroiditis, with TPO-Abs as marker, is a possible endophenotype for bipolar disorder.
A new
species,
Latella & Vonk,
from the island of Rhodes in south-eastern Greece, can be distinguished on the basis of morphological and phylogenetic data. Morphological analysis and DNA sequencing ...of mitochondrial and nuclear protein-coding genes indicated that this species is related to
(Cyprus) and
(Mediterranean regions, with a recent northward expansion). Results supported a genetic separation between the
species of the east Mediterranean regions and those of the northeast Atlantic volcanic islands examined in this study (
,
,
, and
from the Canary islands,
from Madeira, and
from the Azores). The Mediterranean and Atlantic
species appear to be also morphologically distinct.
,
,
, and
(Turkish coast) clearly have a small lobe on the male gnathopod 1 merus. This character was the main diagnostic difference between
(
Lowry, 2013) and
. However, among the six northeast Atlantic island
species only
has a small lobe on the merus of gnathopod 1. Reduction or loss of the lobe in the Atlantic Island species cannot be ruled out; however, molecular phylogenetic analysis leads us to presume that this lobe independently evolved between the east Mediterranean
species and
from Gran Canaria.
PDF
