Species complex or complex species? Integrative taxonomy of the land snail genus Rossmaessleria (Gastropoda,Helicidae) from Morocco and Gibraltar

We applied an integrative approach to re-evaluate the taxonomy of the conchologically highly diverse land snail genus Rossmaessleria from the Rif Mountains in Morocco and from Gibraltar, which has been classified into 12 nominal species so far. An analysis of cox1 and 16S rDNA sequences using the General Mixed Yule-coalescent approach with a single or multiple thresholds, its Bayesian implementation as well as the Automatic Barcode Gap Discovery method indicated that all Rossmaessleria populations can be classified into a single species, R. scherzeri (Zelebor, 1867). This result is confirmed by the lack of diagnostic differences in the genitalia as shown in a principal component analysis of the genital measurements. The variation of shell characters also does not allow an unambiguous subdivision of the complex. However, the populations of a mountain or a mountain ridge share characteristic combinations of shell characters so that they can be classified as geographic subspecies. The delimitation of the subspecies and their distribution is discussed and three subspecies are described as new to science: R. scherzeri periclitata ssp. nov. R. scherzeri ingae ssp. nov., and R. scherzeri eleanorae ssp. nov.

http://zoobank.org/urn:lsid:zoobank.org:pub:187FE235-A257-423F-8FC3-957117546400     

Parallel speciation or long‐distance dispersal? Lessons from seaweeds (Fucus) in the Baltic Sea

Parallel evolution has been invoked as a forceful mechanism of ecotype and species formation in many animal taxa. However, parallelism may be difficult to separate from recently monophyletically diverged species that are likely to show complex genetic relationships as a result of considerable shared ancestral variation and secondary hybridization in local areas. Thus, species' degrees of reproductive isolation, barriers to dispersal and, in particular, limited capacities for long‐distance dispersal will affect demographical structures underlying mechanisms of divergent evolution. Here, we used nine microsatellite DNA markers to study intra‐ and interspecific genetic diversity of two recently diverged species of brown macroalgae, Fucus radicans (L. Bergström & L. Kautsky) and F. vesiculosus (Linnaeus), in the Baltic Sea. We further performed biophysical modelling to identify likely connectivity patterns influencing the species' genetic structures. For each species, we found intraspecific contrasting patterns of clonality incidence and population structure. In addition, strong genetic differentiation between the two species within each locality supported the existence of two distinct evolutionary lineages (F_ST = 0.15–0.41). However, overall genetic clustering analyses across both species' populations revealed that all populations from one region (Estonia) were more genetically similar to each other than to their own taxon from the other two regions (Sweden and Finland). Our data support a hypothesis of parallel speciation. Alternatively, Estonia may be the ancestral source of both species, but is presently isolated by oceanographic barriers to dispersal. Thus, a limited gene flow in combination with genetic drift could have shaped the seemingly parallel structure.     

Where and why? Bees,snail shells and climate: Distribution of Rhodanthidium (Hymenoptera: Megachilidae) in the Iberian Peninsula

Species distribution patterns are widely studied through species distribution models (SDMs), focusing mostly on climatic variables. Joint species distribution models (JSDMs) allow inferring if other factors (biotic interactions, shared phylogenetic history or other unmeasured variables) can also have an influence on species distribution. We identified current distributional areas and optimal suitability areas of three species of the solitary snail‐shell bee Rhodanthidium (Hymenoptera: Megachilidae), and their host gastropod species in the Iberian Peninsula. We undertook SDMs using Maxent software, based on presence points and climatic variables. We also undertook JSDMs for the bees and the snails to infer if co‐occurrence could be a result of biotic interactions. We found that the three bee species: (1) use at least five different species of Mediterranean snails; (2) use empty shells not only for nesting but also for sheltering when there is adverse weather and during the night; (3) have their most suitable areas in the eastern and southern Iberian Peninsula, mostly on limestone areas; and (4) have their optimal range under Mediterranean climatic values for the studied variables. There is positive co‐occurrence of Rhodanthidium with the gastropod species, especially with the snail Sphincterochila candidissima. The contribution of the environmental component to the co‐occurrence is less than that of the residual component in those cases, suggesting that: (i) the use of biotic resources (between Rhodanthidium and the gastropod species); (ii) shared phylogenetic history (between R. septemdentatum and R. sticticum); or (iii) unmeasured variables are largely responsible for co‐occurrence.     

Diversity and abundance of “Pelagibacterales” (SAR11) in the Baltic Sea salinity gradient

The candidate order “Pelagibacterales” (SAR11) is one of the most abundant bacterial orders in ocean surface waters and, periodically, in freshwater lakes. The presence of several stable phylogenetic lineages comprising “Pelagibacterales” correlates with the physico-chemical parameters in aquatic environments. A previous amplicon sequencing study covering the bacterial community in the salinity gradient of the Baltic Sea suggested that pelagibacteral subclade SAR11-I was replaced by SAR11-IIIa in the mesohaline region of the Baltic Sea. In this current study, we investigated the cellular abundances of “Pelagibacterales” subclades along the Baltic Sea salinity gradient using catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). The results obtained with a newly designed probe, which exclusively detected SAR11-IIIa, were compared to CARD-FISH abundances of the marine SAR11-I/II subclade and the freshwater lineage SAR11-IIIb (LD12). The results showed that SAR11-IIIa was abundant in oligohaline–mesohaline conditions (salinities 2.7–13.3), with maximal abundances at a salinity of 7 (up to 35% of total Bacteria, quantified with a universal bacterial probe EUB). As expected, SAR11-I/II was abundant (27% of EUB) in the marine parts of the Baltic Sea, whereas counts of the freshwater lineage SAR11-IIIb were below the detection limit at all stations. The shift from SAR11-IIIa to SAR11-I/II was confirmed in the vertical salinity gradient in the deeper basins of the Baltic Sea. These findings were consistent with an overlapping but defined distribution of SAR11-I/II and SAR11-IIIa in the salinity gradient of the Baltic Sea and suggested the adaptation of SAR11-IIIa for growth and survival in mesohaline conditions.     

Studies from the “UWL Helgoland” on the macrobenthic fauna of rocks and boulders in Lübeck Bay (western Baltic Sea)

During a fortnight's saturation mission with the Underwater Laboratory (UWL) Helgoland in May and June 1975, samples of the macrobenthic fauna of rocks and boulders at 15 m depth in the Lübeck Bay were collected from the same area as in October 1974, using a diver-operated suction sampler. Salinity varied from 11.1 to 15.0 S and water temperature from 7.5° C to 11.5° C. Visibility was usually about 3 to 4 m. On average, 10.449 individuals/m² were recorded in 1975 compared to 30.474 individuals/m² in 1974. Two species, the ascidianDendrodoa grossularia and the polychaetePolydora ciliata account for 90.8% of the total number of individuals sampled. Five species (Dendrodoa grossularia, Nereimyra punctata, Neoamphitrite figulus, Asterias rubens, Facelina drummondi) were significantly less abundant than in 1974, while two species and one group of species (Anaitides maculata, Corophium bonelli, Nemertini indet.) were more abundant in 1975. As in 1974, the angle of inclination of the substrate showed no relationship with species composition. In 1974, four motile benthic invertebrates,Nereimyra punctata, Idothea baltica, Diastylis rathkei, andFacelina drummondi were observed swarming. In 1975, onlyI. baltica was observed swarming and the individuals seemed to be less active than in 1974, perhaps related to the lower water temperatures recorded in May and June 1975 compared to those in October 1974.     

Fishermen’s knowledge and conservation attitudes: focus on the great cormorant Phalacrocorax carbo (Linnaeus, 1758) in the Minho River,Portugal

Aquatic Ecology - Considerate the attitudes of traditional communities and their local ecological knowledge (LEK) can contribute to better policymaking and more appropriate management plans. Thus,...     

Diversity,consistency, and seasonality in parasite assemblages of two sympatric marine fish Pagrus pagrus (Linnaeus, 1758) and Pagellus bogaraveo (Brünnich, 1768) (Perciformes: Sparidae) off the coast of Algeria in the western Mediterranean Sea

Various host characteristics (i. e., feeding habits, geographic distribution) and habitat characteristics (i.e., seasonality) influence the structure of parasite assemblages. To compare the parasite assemblages of hosts representatives of two genera of the same fish family, simultaneously occupying a geographic region, and to examine if seasonal variations influence parasite occurrence and abundance, we examined the parasite assemblages of two sympatric marine fish, Pagrus pagrus (n = 308) and Pagellus bogaraveo (n = 315) off the coast of Algeria in the western Mediterranean. Specimens were collected during summer and autumn over three consecutive years (2014–2016). Parasite assemblages were high in species richness and abundance. We compiled an inventory of 40 parasite taxa, including ectoparasitic monogeneans and crustaceans, and endoparasitic trematodes, cestodes, acanthocephalans, and nematodes. Endoparasite taxa primarily consisted of adult gastro-intestinal parasites and long lived larval helminths. Information on the parasite community structure and seasonal variations in parasite populations of these two hosts from the Mediterranean is here provided. Observed patterns of composition, diversity, dominance, and similarity indicate an overall consistency in assemblage structure. Although each host species harbored distinct parasite communities, they shared a high proportion of parasite species suggesting similar use of a common local pool of parasites. However, most shared species did not contribute to structuring the assemblages. Seasonal patterns in parasite abundance were observed for both hosts, with peak prevalence, abundance, and diversity in autumn. Results suggest that, regardless of a common pool of parasites being available to sympatric species, several ecological filters over time, led to distinct, independent variations in the parasite assemblages in each species.     

Endemic to Borneo or the Korean Cheju Island? Mystery of mislabelled land snail solved after 170 years (Gastropoda: Cyclophoroidea: Alycaeidae)

ABSTRACT

The alycaeid Cyclostoma spiracellum Adams & Reeve, 1850 (currently Dicharax spiracellum) was described from Borneo, based on shells from the expedition of HMS Samarang (1843–1846). A comparison with material of nearly all alycaeid species revealed that D. spiracellum is conchologically identical to Alycaeus kurodai Pilsbry & Hirase, 1908, which is described from the Korean Cheju Island. The land operculate snail fauna of Korea and Borneo do not overlap, and D. spiracellum has not been found in Borneo in spite of intensive recent collecting efforts. Therefore, it must be concluded that D. spiracellum does not occur in Borneo and that it was probably obtained when the Samarang visited Cheju Island, and the specimens were most likely mislabelled. As a result, A. kurodai is considered herein as a junior synonym of C. spiracellum, and the type locality of C. spiracellum (Borneo) is corrected to ‘probably Cheju Island, South Korea’. Chamalycaeus kurodai duplicatus Kuroda & Miyanaga, 1943 is treated as Dicharax spiracellum duplicatus (Kuroda & Miyanaga, 1943).     

“More than meets the eye”: phylogeographic inferences and remarkable cryptic diversity and in endemic catfish Parotocinclus (Loricariidae: Hypoptopomatinae) from neglected and impacted basins in South America

Conservation Genetics - The restricted range, taxonomic uncertainties and the apparent phylopatric behavior of Parotocinclus (dwarf plecos) make this fish group an excellent model to infer...     

A life in the surf zone: Age and feeding habits of the pompano (Trachinotus ovatus,Linnaeus, 1758) on the beaches of the Gulf of Cádiz (south-west Iberian Peninsula)

Surf zones are crucial habitats for many fish species, where they spend the initial stages of their lives, finding food and shelter. One such species is the pompano (Trachinotus ovatus). The aim of this study was to examine the age and diet of the pompano within the surf zone, along with any potential variations in the environment. The average size of the specimens was 10.61 ± 4.91 cm. The length–weight relationship was total weight (TW) = 0.0136*total length (TL)^2.8512 (parameter a: 95% C.I. : 0.0130–0.0142 and parameter b: 95% C.I. : 2.8318–2.8705). The most abundant age classes were 0+ and 1+, making up 97% of the captured specimens, with significant differences in the abundance of age classes depending on the time of the day and season. The pompano primarily fed on clupeiforms, copepods, and mysids, with significant variations in diet based on the time of the day, season, and size of the specimens. This study contributes new information about the use of the surf zone by T. ovatus in its early years of life, underscoring the importance of these areas and their role as an additional ecosystem service.     

Flyway homogenisation or differentiation? Insights from the phylogeny of the sandpiper (Charadriiformes: Scolopacidae: Calidrinae) wing louse genus Lunaceps (Phthiraptera: Ischnocera)

The wing louse genus Lunaceps, is the most speciose chewing louse (Phthiraptera) genus inhabiting sandpipers (Charadriiformes: Calidrinae) and is known from almost all sandpiper species. The hosts follow specific flyways from the Arctic breeding grounds to wintering locations in the southern hemisphere, and often form large mixed-species flocks during migration and wintering. We estimated a phylogeny of Lunaceps based on three mitochondrial loci, supporting monophyly of the genus but revealing extensive paraphyly at the species level. We also evaluated the relative importance of flyway differentiation (same host species having different lice along different flyways) and flyway homogenisation (different host species having the same lice along the same flyway). We found that while the lice of smaller sandpipers and stints show some evidence of flyway homogenisation, those of larger sandpipers do not. No investigated host species migrating along more than one flyway showed any evidence of flyway differentiation. The host-parasite associations within Lunaceps are in no case monophyletic, rejecting strict cospeciation.     

Taxonomy and distribution of species of Gastrocopta Wollaston 1878 (Mollusca: Gastropoda: Gastrocoptidae) from the Galápagos Islands (Ecuador)

ABSTRACT

A revision of Gastrocopta from the Galápagos Islands (Ecuador) is made. Four new species from Pinzón, Santa Cruz and Floreana Islands are described; species previously known are redescribed and new locations are added. Gastrocopta (Gastrocopta) reibischi is revalidated through new records from Floreana, Isabela and San Bartolomé Islands. Shell shape and the number, morphology and disposition of the apertural barriers support the discrimination of the taxa. The species have cylindrical to pupoid shells; the number of apertural barriers – differentiated as lamellae, folds and nodulae – varies between 4 and 11, almost completely occluding the aperture in the more complex cases. These structures are: angular-parietal, infraparietal, supracolumellar, columellar, subcolumellar lamellae, and supernumerary, basal, infrapalatal, lower-palatal, interpalatal, upper-palatal and suprapalatal folds. In addition to this classic scheme, a supernumerary fold and a nodule are added. Calcareous concretions – pustulae – are found in several species, mainly located in the peristome. The aulacognathous jaw and radular dentition formulae of Gastrocopta (Gastrocopta) clausa and Gastrocopta (Gastrocopta) munita, are described and photographed for the first time.     

Population changes in sympatric Great and Long-tailed Cormorants (Phalacrocorax carbo and P. africanus): the effects of niche overlap or environmental change?

Between January 1993 and January 1995, the number of Great Cormorants (Phalacrocorax carbo) using Lake Naivasha, Kenya (00° 45 S, 36° 20 E) for foraging and resting increased 56%, while the number of sympatric Long-tailed Cormorants (Phalacrocorax africanus) decreased 64%. In 1995 and 1996, we documented habitat changes and conducted monthly population and resource-use surveys of the two species in an attempt to discover the most likely reasons for these changes. The increase in Great Cormorants was probably the result of immigration from nearby Lake Nakuru due to extreme water level reductions there. Lake Naivasha also experienced falling water levels and transparency during this period, but these changes were not as severe and are not considered likely reasons for the decline in Long-tailed Cormorant numbers. Despite some probable dietary overlap, the two species were well separated in terms of foraging locations, foraging methods, resting habitats and breeding timing. The decline in Long-tailed Cormorant numbers may be connected with increased disturbance by fishermen along the lake littoral, this species' primary feeding location.     

First record of the occurrence of "gill disease" in Mytilus edulis trossulus from the Gulf of Gdańsk (Baltic Sea, Poland)

We are presenting the first report of the occurrence of "gill disease" in Mytilus edulis trossulus from the southern Baltic Sea, Gulf of Gdańsk (Poland). The disease preliminary diagnosis was based on the presence of white and yellow "spots" causing deep indentations in the gills with degeneration, destruction and necrosis of gill filaments. Average prevalence of gill erosion in the blue mussels population was 15.8%. According to other authors, gill erosion may affect over 80% of the bivalve population resulting in mortality rates of up to 40%. The origin of the gill erosion remains unknown, but viruses are most likely involved in the etiology of these pathological conditions. The disease as such may indicate a decrease in the immunological resistance of organisms to infections and inflammations directly or indirectly caused by harmful factors in the ambient environment. Furthermore, the occurrence of numerous pathologies in bivalves is a particular problem in the Gulf of Gdańsk being a low biodiversity ecosystem. Pathologies reduce bilvalves' reproduction ability, worsen their physiological condition and increase their mortality rate. Those factors may also pose a significant ecological danger and lead to negative alterations of the ecosystem.     

Trace metals in the common mussel,Mytilus edulis (L.), and in the alga Fucus vesiculosus (L.) from the region of the sound (Öresund)

Concentrations of zinc, cadmium, lead and iron were determined in whole soft parts of mussels, Mytilus edulis (L.), and in growing tips of the alga Fucus vesiculosus (L.) from a total of 20 locations in the area of the Sound between Sweden and Denmark. Pollution profiles produced for each metal were similar in any one of the species studied but the profiles for metals in M. edulis were distinct from those for metals in F. vesiculosus. Results for mussels agreed broadly with those reported previously for this region, indicating a northward decrease in available metal concentrations. By contrast, results for algae showed few differences in metal availability throughout the study area, although some local effects were evident.The differences in the pollution profiles exhibited by these two organisms depend on their response to different portions of the total trace metal load of ambient waters. Results from the alga agree well with available data on the concentrations of trace metals in solution in waters of the Sound. The alga thus appears to be responding only to metals in solution, as suggested by previous authors. By contrast, the major proportion of the total body load of metals in mussels is derived from ingested phytoplankton. The pollution profiles exhibited by mussels may be explained if phytoplankton from the Baltic Sea contain higher concentrations of trace metals than do those from Kattegat. Possible mechanisms for the production of such differences in the metal contents of the two phytoplankton populations, and the ecological implications of these differences, are briefly discussed.     

Are black flies of the subgenus Wilhelmia (Diptera: Simuliidae) multiple species or a single geographical generalist? Insights from the macrogenome

Organisms with vast distributions often represent geographical mosaics of cryptic species. The black fly Simulium (Wilhelmia) lineatum is among the most widely distributed members of the family Simuliidae, ranging from the British Isles to eastern China. Rather than viewing S. lineatum as a possible aggregate of multiple species, taxonomists have suggested a more inclusive taxon with additional synonyms. Accordingly, S. lineatum is an ideal candidate for testing the hypothesis that a wide geographical distribution signals the presence of more than one species. A cytogenetic approach was used to probe the macrogenome of S. lineatum and other taxa proposed by taxonomists as conspecific. The banding patterns in the polytene chromosomes of 480 larvae from 15 countries across the Palearctic Region revealed 128 rearrangements of the complement. All rearrangements were autosomal and 89% were inversions nonrandomly distributed among species and among chromosome arms. The analyses clarify long‐standing confusion over previously proposed names and reveal a longitudinal succession of four species sequentially replacing one another from west to east: Simulium lineatum s.s., Simulium balcanicum, Simulium turgaicum, and Simulium takahasii. Thus, S. turgaicum is recalled from synonymy and the other three species are validated. Within the most‐represented species, S. balcanicum, the frequency of inversions follows a longitudinal gradient with a north–south bias; as the distance between the sites increases along this north‐west–south‐east axis, the similarity of inversion frequencies between sites decreases. Validation of the concept that broadly distributed black flies are composites of structurally similar species provides a framework for guiding discovery of additional biodiversity. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 163–183.