First record of the yellowbar angelfish Pomacanthus maculosus (Forsskål, 1775) (Actinopterygii: Pomacanthidae) in the Hellenic Seas

Biological invasions are one of the main drivers of modern human-induced species losses. Research on the distribution of alien species and their pathways of introduction is essential for understanding and tackling the invasion process. A comprehensive overview on invasive alien plant (IAP) species in Romania is lacking. With this paper, we aim to contribute to filling this gap and to provide a visualization of national patterns regarding plant species invasions, geographical origins and pathways of introductions. Based on plant species occurrence records in the published literature and herbaria we compiled a national database of 102 invasive and potentially invasive alien plant species. We georeferenced 42776 IAP species occurrences and performed an analysis of their spatial patterns. The spatial analyses revealed a biased sampling, with clear hotspots of increased sampling efforts around urban areas. We used chord diagrams to visualize the pathway of introduction and geographical origins of the IAP species, which revealed that species in Romania originate mainly in North and Central America, while the dominant pathway of plant introduction was horticulture. Our results provide an important baseline in drafting management and action plans, as invasive alien plant species represent a priority for the European Union through the Biodiversity Strategy for 2030, and a good starting point for various analyses as the database is further developed and regularly updated.

Species range expansions are crucial for understanding niche formation and the interaction with the environment. Here, we studied the bumblebee Bombus haematurus Kriechbaumer, 1870, a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Europe without human-mediated dispersal (i.e., it is a natural spread). After updating the global distribution of this species, we investigated if niche shifts took place during this range expansion between newly colonized and historical areas. In addition, we have explored which climatic factors may have favored the natural range expansion of the species. Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018, a natural expansion over an area that equals 20% of the historical distribution. In addition, this bumblebee performs generalism in flower visitation and it occurs in different habitats, although a preference for forested areas clearly emerges. The land-use associated with the species in the colonized areas is similar to the historical distribution, indicating that no major niche shifts occurred during the spread. Furthermore, in recently colonized localities, the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases. These findings document a case of natural range expansion due to environmental change rather than due to niche shifts, and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.

The list of marine alien species in Hellenic waters is updated taking into account new findings (published and unpublished data). According to the present work, the number of these species has increased from 90 (known until end 2003) to 128. Most of them are zoobenthic species followed by fish and macroalgae. An interannual analysis revealed an important increase of alien species during the last years. The study of their geographic distribution showed that their majority is present in the southeastern Aegean. More than 55% of them are well established, while about 40% are casual records. Their main pathway of introduction seems to be the Suez Canal followed by shipping, whereas the Straits of Gibraltar, aquaculture and the Straits of Dardanelles appear to play a less important role in their invasion of Hellenic waters. These findings are discussed considering environmental and anthropogenic factors.

The purpose of this note is to propose recognition of Porites hawaiiensis Vaughan, 1907, (Figure 1A–D) a species currently regarded as a junior synonym of Porites rus (Forskål 1775), as a valid species, based on molecular and morphological characteristics. Vaughan (1907 p. 217, pl 91 figs 2, 2a) described Porites (Synaraea) hawaiiensis from a specimen collected from Kalihi Harbor on the island of O‘ahu, Hawai‘i (Figure 1 C). Porites (Synarea) hawaiiensis was also reported from the Marshall Islands by Wells (1954 p. 455, pl 170 figs 6,7). Porites hawaiiensis was subsequently thought to be a junior synonym of Porites (Synaraea) convexa Verrill, 1864, due to the small calices that are characteristic of the subgenus Synaraea (Maragos 1977). Later both species were made synonyms of P. (Synaraea) rus, Forskål 1775 (Veron & Pichon 1982; Cairns 1991). Vaughan, 1907 described the calices of P. hawaiiensis as “densely spinulose” with “coenchyma” equaling, or exceeding the 0.5 mm diameter of the calices, and a pitted star shaped space between the pali (Figure 1C,D). In the absence of living specimens, the Vaughan, 1907 type specimen was difficult to distinguish from newly settled P. rus colonies, but upon closer examination in the field, Maragos et al. (2004) recognized small coral colonies that appeared to match the description of P. hawaiiensis. This species can readily be distinguished from Porites rus and other Porites by very small colony size (<10cm), mottled yellow and green-brown coloration, encrusting form, and thicket of spiny denticles between distantly spaced corallites (Figure 1A–D). Genetic data from Forsman et al. 2009 confirmed that this small ‘patch coral’ is distinct from P. rus (n = 3 of each species; uncorrected pair-wise distance; mtCOI = 0.5% ± 0.2 SE; mtCR = 0.7%, and nuclear ITS = 14.2 % ± 1.3 SE), and is also distinct from all other Hawaiian congeners. The genetic data further indicated that ‘Synaraea’ was surprisingly closely related to other Poritids and may not warrant sub-genus status (Forsman et al. 2009). Fenner (2005) referred to this same small ‘patch coral’ as Porites cf. bernardi, however; P. bernardi Vaughan, 1907 type specimens were coralliths (Figure 1E) with calices similar in size to those of most other Porites (Figure 1 F). The geographic range of Porites hawaiiensis is unknown, although it is abundant throughout the Northwest and Main Hawaiian Islands, and has been reported at depths from 1 to 55m (30 fathoms) in the Marshall Islands (Wells 1954). This species can be easily overlooked; it tends to grow in cryptic habitats (cracks, crevices, and interstitial spaces), and at first glance, the small patches of colonies (0.5–10cm) can be confused with crustose coralline algae, or new recruits of other Porites species. This species is remarkable because of its small adult colony size; a curious life history characteristic since many Porites in the Pacific can be among the largest and longest-lived scleractinain corals (Brown et al. 2009). We propose that this small ‘patch coral’ is a distinct species, and that P. hawaiiensis is the most appropriate name.

Freshwater eels in the family Anguillidae spend a majority of their adult life in freshwater but migrate to the ocean to spawn and die. Because freshwater eels are believed to have a long larval period in the open ocean, it is unclear how the present global distribution of species arose. A stock of freshwater eels of the family Anguillidae was found on Palmyra Atoll in the central Pacific Ocean, in June 2003. In October 2003, a single eel specimen was caught using a hand net from this small group of eels on Palmyra Atoll. Morphological and molecular characters (12S and 16S mitochondrial rRNA and cytochrome b mtDNA sequences) were used to identify the species as Anguilla marmorata Quoy & Gaimard. The discovery of these eels on Palmyra supports the hypothesis of natural range expansion from the Indo-Pacific eastward to the Galapagos through the Line Islands, but further analysis of oceanic currents and more variable genes are required to assess whether humans are involved in the recent spread of Anguilla marmorata to these new locations.

Main biological features were assessed for the first time in the deep-water shark Etmopterus spinax from Hellenic waters by examining 150 individuals caught incidentally in the bottom-trawl commercial fishery off Skyros island. Females outnumbered males and the overall sex ratio was 1.38:1. Females ranged from 122 to 311 mm in total length (LT ) and males from 129 to 270 mm LT , both exhibiting positive allometric growth. Total length-total mass relationships and frequency distributions did not show significant differences between females and males. Sexual dimorphism was not either found by analysing 56 different morphological characteristics. The effect of sex and season was more prominent on the gonadosomatic and hepatosomatic indices compared to the relative condition factor. Most of the individuals were sexually immature, with two specimens classified as mature, one gravid female reaching 311 mm LT with undeveloped gonads and enlarged uteri with embryos, and one male reaching 270 mm LT with enlarged gonads and rigid claspers with hooks. The present study highlights the importance of the sampling location as a breeding and nursery ground for E. spinax in the eastern Mediterranean Sea that should be taken into account for the species' conservation considering its intrinsic characteristics, which make it vulnerable to fishing pressure.

AimNatural range expansions and human‐mediated colonizations usually involve a small number of individuals that establish new populations in novel habitats. In both cases, founders carry only a fraction of the total genetic variation of the source populations. Here, we used native and non‐native populations of the green anole,Anolis carolinensis, to compare the current distribution of genetic variation in populations shaped by natural range expansion and human‐mediated colonization.LocationNorth America, Hawaiian Islands, Western Pacific Islands.MethodsWe analysed 401 mtDNAhaplotypes to infer the colonization history ofA. carolinensison nine islands in the Pacific Ocean. We then genotyped 576 individuals at seven microsatellite loci to assess the levels of genetic diversity and population genetic differentiation for both the native and non‐native ranges.ResultsOur findings support two separate introductions to the Hawaiian Islands and several western Pacific islands, with subsequent colonizations within each region following a stepping‐stone model. Genetic diversity at neutral markers was significantly lower in the non‐native range because of founder effects, which also contributed to the increased population genetic differentiation among the non‐native regions. In contrast, a steady reduction in genetic diversity with increasing distance from the ancestral population was observed in the native range following range expansion.Main conclusionsRange expansions cause serial founder events that are the spatial analogue of genetic drift, producing a pattern of isolation‐by‐distance in the native range of the species. In human‐mediated colonizations, after an initial loss of genetic diversity, founder effects appear to persist, resulting in overall high genetic differentiation among non‐native regions but an absence of isolation‐by‐distance. Contrasting the processes influencing the amount and structuring of genetic variability during natural range expansion and human‐mediated biological invasions can shed new light on the fate of natural populations exposed to novel and changing environments.

During field investigations of deep-reefs off the coast of Curaçao in the Lesser Antilles, Caribbean Sea, a female specimen was collected of an undescribed micro-pagurid crab with striking dorso-ventral flattening of the right cheliped. It was further characterized by a reduced branchial formula, fourth pereopods with grasping-like spines instead of typically pagurid rasp-like scales, nearly symmetrical uropods and telson, and a minute pair of first pleopods (gonopods). The single specimen was discovered in samples from the rariphotic zone (~130-309 m) obtained using a suction sampler operated from the manned submersible R/V Curasub over cryptic habitats and surfaces populated by communities of sessile macro-organisms. As the specimen does not fit any known pagurid taxon, we regard it to represent a new monotypic genus. We fully describe this new micro-pagurid as Raripagurus roseangelae n. gen., n. sp. and also provide photographs of its live coloration. The CO1 barcode for the holotype in the Barcode of Life Database and GenBank accession number are included as part of the description for any future phylogenetic investigations.

Can the variation of physical and biological parameters explain the distinct sessile communities from cryptic habitats across a coastal bay?

Gunnel species (family Pholidae), characterized by an elongated bar-like body and usually found in shallow coastal waters, are mostly restricted to temperate to subarctic waters in the Northern Pacific Ocean, although some in the Western Pacific are distributed southward to the northern East China Sea. Despite the absence of previous records from subtropical and tropical waters, a single specimen of the fish family Pholidae was recently trawled off southwestern Taiwan. Examination on the morphological characteristics and DNA barcoding revealed this is a Pholis fangi (Wang Wang 1935), a species previously recorded only from cold waters in the Bohai and Yellow seas. As a consequence, the present specimen represents the first record of the species from the subtropical South China Sea coast of Taiwan, as well as an isolated southernmost record of this species, more than 1,000 km southward from the otherwise known distribution. Detailed morphology and fresh coloration are described.

Warming across the low Arctic is increasing tundra vegetation productivity and facilitating the expansion of upright shrubs. We modeled the effects of warming on habitat suitability in green alder, dwarf birch, Labrador tea, bog bilberry, and lingonberry and assessed the influence of data type (true absence or pseudo-absence) on species distribution models (SDMs). We generated SDMs using the two absence data types under current (1970–2000) and future (2061–2080) climate projections. Our results show that warming leads to range expansion of all shrubs, though responses vary in magnitude and extent, with mean increases in suitability ranging from 0.080 (Labrador tea) to 0.369 (lingonberry) with true absences. Differences in driving variables and suitability projections suggest that physiological and ecological variability between species mediate responses to warming. Between data types, we observed inconsistencies in model performance, suitability projections, and variable importance. Bog bilberry and lingonberry exhibited larger differences in suitability (0.201 and 0.288, respectively), whereas alder showed similar responses (difference of 0.01). These results are important to consider when assessing changes in habitat suitability or identifying environmental or climatic determinants of species’ distributions. We suggest further development of open data repositories, facilitating access to true absence data to support conservation and land use planning.

AimsWe identify alien reptiles and amphibians, invaders or not, in Brazil and evaluate the following: (a) which alien species are found in the country; (b) where they originate from; (c) how they are distributed; (d) why and how they were introduced; and (e) which factors affect the record incidences and local richness of these species.LocationBrazil.MethodsWe conduct a comprehensive survey of different data sources to collect records of alien amphibians and reptiles. We then use a causal model approach to evaluate the influence of space, climate, anthropogenic predictors, and introduction pathways on alien richness and number of records.ResultsWe find a total of 2,292 records of 136 species of alien reptiles and amphibians. Although species from many regions of the world can be found, most are snakes, lizards and anurans originating in the Americas. Although records of alien amphibians and reptiles are found throughout Brazil, they are concentrated in more economically developed areas. Socio‐economic measures have both a direct and indirect causal relationship over the distribution of alien species and affect all introduction pathways, which are key factors explaining the alien species’ distribution. Pet trade was directly related to alien diversity, while all the three introduction pathways contributed to explain the number of records.Main ConclusionsWe reveal a high diversity of alien amphibians and reptiles widespread in an already megadiverse country. The finding that alien richness occurs in highly populated and wealthy areas and that it is linked to the pet trade helps to direct efforts towards the surveillance and prevention of the spread of alien species in Brazil. A higher record incidence is associated with species introduced accidentally or for human consumption, mainly represented by a few already invasive widespread species, impairing management measures.

In the face of ongoing habitat loss and fragmentation, examining the genetic effects of range expansion can provide insight into the resilience and adaptability of large carnivore populations returning to parts of their former range. This study investigates the genetic structure of the Eurasian lynx (Lynx lynx) population during its natural range expansion into southern Sweden, an area from which it had been extirpated for over a century. We utilized genomic data from 600 individual lynx collected throughout the recolonization period to assess heterozygosity, inbreeding, and genetic differentiation. Our results indicate no significant genetic structure or barriers to gene flow during this recolonization event, despite potential physical barriers such as lakes, farmland, and human infrastructure. Observed and expected heterozygosity, as well as the inbreeding coefficient did not show significant variation over time or across latitude, suggesting that connectivity with the source population was maintained. Spatial principal component analysis, cluster analysis, and discriminant analysis of principal components further supported these findings, showing little spatial or temporal structure. This lack of genetic structure contrasts with the experience of smaller and more isolated lynx populations, which have become inbred. Our study, thus, provides valuable insights into the natural range expansion of a large carnivore in human-dominated landscapes and underscores the importance of ensuring genetic connectivity for successful recolonization and conservation efforts.

We studied the relation of light with coral colony morphology and coral distribution over a 5 to 50 m reef slope. We describe the characteristics of 6 species of the genus Madracis in relation to the light (photosynthetically active radiation (PAR): 400 to 700 nm) colonies receive at a small spatial scale (1 to 10 cm). Species differ in their response to light but we could distinguish 3 strategies: (1) Species strive for maximum light capture and colonies occur above a threshold light value. This limits the distribution of such species toward greater depths. These species are found in shallow ( 30 m) of the reef slope. Colony morphological variation is also unrelated to variation in the amount of light the colonies receive. (3) Species prefer low light habitats. Such species are found over the entire reef slope and they show a bimodal light preference. One part of the population (1st mode) prefers the maximum amount of light available at a particular depth. The other part of the population (2nd mode) prefers cryptic habitats with low light levels (5 to 60 µmol photons m -2 s -1 ). In these species, morphological variation in colony shape relates to light availability. Structural complexity of the reef surface within the same depth causes such vari- ation in local light availability. This variation ranges between the maximum value at a depth pre- dicted by physical laws and the minimal values encountered in cryptic habitats. The large variation in available light occurring over spatial scales as small as 10 cm distorts the direct relation between depth and light. Depth and light are only correlated as ecological factors for species that strive for maximum light capture (Strategy 1 or 2). A large depth distribution does not imply adaptation to a large light range when species have a strict preference for cryptic light environments. For such species (Strategy 3) depth is not a proxy for light. The different light strategies of species are related to morphological variation and species exploration of the reef habitat.

The presence and the establishment of Idotea hectica is reported for the first time in the Hellenic seas on the basis of three adult specimens and a juvenile collected from Posidonia oceanica meadows close to the main town of Rhodes Island, Aegean Sea. Common and contrasting characters between this and other species of the genera Idotea and Pentidotea are briefly discussed. Furthermore, following a westward expansion along the eastern Mediterranean coasts, Matuta victor was discovered for the first time in Hellenic waters on the basis of a single specimen from the northeast of Rhodes Island.