Biological invasions are a population-level rather than a species-level phenomenon.

Biological invasions pose a rapidly expanding threat to the persistence, functioning and service provisioning of ecosystems globally, and to socio-economic interests. The stages of successful invasions are driven by the same mechanism that underlies adaptive changes across species in general-via natural selection on intraspecific variation in traits that influence survival and reproductive performance (i.e., fitness). Surprisingly, however, the rapid progress in the field of invasion science has resulted in a predominance of species-level approaches (such as deny lists), often irrespective of natural selection theory, local adaptation and other population-level processes that govern successful invasions. To address these issues, we analyse non-native species dynamics at the population level by employing a database of European freshwater macroinvertebrate time series, to investigate spreading speed, abundance dynamics and impact assessments among populations. Our findings reveal substantial variability in spreading speed and abundance trends within and between macroinvertebrate species across biogeographic regions, indicating that levels of invasiveness and impact differ markedly. Discrepancies and inconsistencies among species-level risk screenings and real population-level data were also identified, highlighting the inherent challenges in accurately assessing population-level effects through species-level assessments. In recognition of the importance of population-level assessments, we urge a shift in invasive species management frameworks, which should account for the dynamics of different populations and their environmental context. Adopting an adaptive, region-specific and population-focused approach is imperative, considering the diverse ecological contexts and varying degrees of susceptibility. Such an approach could improve and refine risk assessments while promoting mechanistic understandings of risks and impacts, thereby enabling the development of more effective conservation and management strategies.

Economic costs of non-native species in Türkiye: A first national synthesis.

Biological invasions are increasingly recognised as a major global change that erodes ecosystems, societal well-being, and economies. However, comprehensive analyses of their economic ramifications are missing for most national economies, despite rapidly escalating costs globally. Türkiye is highly vulnerable to biological invasions owing to its extensive transport network and trade connections as well as its unique transcontinental position at the interface of Europe and Asia. This study presents the first analysis of the reported economic costs caused by biological invasions in Türkiye. The InvaCost database which compiles invasive non-native species' monetary costs was used, complemented with cost searches specific to Türkiye, to describe the spatial and taxonomic attributes of costly invasive non-native species, the types of costs, and their temporal trends. The total economic cost attributed to invasive non-native species in Türkiye (from 202 cost reporting documents) amounted to US$ 4.1 billion from 1960 to 2022. However, cost data were only available for 87 out of 872 (10%) non-native species known for Türkiye. Costs were biased towards a few hyper-costly non-native taxa, such as jellyfish, stink bugs, and locusts. Among impacted sectors, agriculture bore the highest total cost, reaching US$ 2.85 billion, followed by the fishery sector with a total cost of US$ 1.20 billion. Management (i.e., control and eradication) costs were, against expectations, substantially higher than reported damage costs (US$ 2.89 billion vs. US$ 28.4 million). Yearly costs incurred by non-native species rose exponentially over time, reaching US$ 504 million per year in 2020-2022 and are predicted to increase further in the next 10 years. A large deficit of cost records compared to other countries was also shown, suggesting a larger monetary underestimate than is typically observed. These findings underscore the need for improved cost recording as well as preventative management strategies to reduce future post-invasion management costs and help inform decisions to manage the economic burdens posed by invasive non-native species. These insights further emphasise the crucial role of standardised data in accurately estimating the costs associated with invasive non-native species for prioritisation and communication purposes.

Turcinoemacheilus ekmekciae, a new dwarf loach from upper Tigris and Euphrates (Teleostei: Nemacheilidae).

Turcinoemacheilus ekmekciae, new species, from upper Euphrates and Tigris drainages is distinguished from other species of Turcinoemacheilus in Western Asia by having a dark stripe broader than the eye diameter along the lateral line, rarely possessing roundish blotches, 5-6 mandibular pores in mandibular canal, a comperatvely smaller head, a deeper body, and a greater pre-pelvic distance. Our specimens collected from the upper Great Zab, near the type locality of Turcinoemacheilus kosswigi, showed notable genetic divergence (a minimum K2P of 3.3%) from sequences reported as T. kosswigi in previous studies. Despite morphological similarities, this molecular difference suggests that the populations analysed in previous studies may represent a potential new species of Turcinoemacheilus, which we tentatively named as Turcinoemacheius cf. kosswigi. Molecular data also suggest that T. ekmekciae is characterized by a minimum K2P distance of 3.5% from Turcinoemacheilus minimus and T. cf. kosswigi. The three methods for species delimitation (assemble species by automatic partitioning [ASAP], Poisson tree processes [PTP], and multi-rate PTP [mPTP]) that were utilized for testing species assignments consistently identified our test group as a distinct species.

Long-term investigation of microplastic abundance in Squalius species in Turkish inland waters.

Examining the enduring alterations in microplastic (MP) concentrations within fish in inland waters is of utmost importance in understanding the historical trajectory of plastic waste and formulating consequential predictions regarding upcoming pollution levels. This study includes the collection of fish samples from 22 different river basins in Türkiye and all Squalius species distributed in Türkiye, covering the years 2004-2018, and examined the presence of MP in museum specimens' gastrointestinal tracts (GITs). 331 specimens were examined, and microplastic was observed in 20.8% (69). A mean value of 0.27 ± 0.19 MP per individual was observed, resulting in a cumulative score of 91 MP. Most observed MPs were composed of fiber, representing 79.1% of the total. The polymer types identified were mostly polyethylene (PE) at 38.5% and polyethylene terephthalate (PET) at 29.7%. The black color was prominent among MPs, and MP length ranged between 101 and 4963 µm. The analysis revealed no statistically significant difference in the mean MP values across different years and basins. There is no substantial correlation between the abundance of MP and the sizes of fish, population density, or quantities of plastic production. The data indicate that MP has persistently acted as a contaminant in freshwater ecosystems over an extended period. It is projected that the laundering of synthetic textiles serves as the primary contributor to MP contamination in freshwater bodies. Our results offer significant baseline data on the pervasive issue of MP pollution in the freshwater environment. These findings enable us to gain profound insights into the current state of MP contamination in fish residing in lotic systems while empowering us to make accurate predictions about its future trajectory.

Oxynoemacheilus marmaraensis, a new species from the Susurluk River, Türkiye (Teleostei: Nemacheilidae).

Oxynoemacheilus marmaraensis, new species, is restricted to the Susurluk River. It is distinguished from all the named species of Oxynoemacheilus in the northwestern Anatolian by the flank with a vermiculate pattern and the presence of a suborbital groove in males, and no axillary lobe at the base of the pelvic fin. It also differs from the closest species, Oxynoemacheilus kentritensis, by having 58 nucleotide substitution sites. The genetic distance is 10.49% between O. marmaraensis and O. kentritensis. Phylogenetic analyses and species delimitation tests (Poisson tree processes and assemble species by automatic partitioning) support the validity of O. marmaraensis as a distinct species.

Phoxinus abanticus, a new species from the Lake Abant drainage in Türkiye (Teleostei: Leuciscidae).

Phoxinus abanticus, a new species, is described from the Lake Abant basin. It is distinguished from Phoxinus species in Türkiye and adjacent waters by the presence of fewer lateral line scales (60-69, vs. 75-91 in Phoxinus colchicus, 75-90 in Phoxinus strandjae); a deeper caudal peduncle (caudal peduncle depth: 1.8-2.3 times in length, vs. 2.4-2.9 in P. colchicus; 2.5-3.2 in P. strandjae); the absence of scales in the breast of males (vs. present); and ventral body reddish in nuptial colouration pattern for male (vs. brackish). The new species, P. abanticus, is also distinguished from its closest relative, P. strandjae, by a minimum of 3.40% genetic distance in the mtDNA cytochrome b (cyt b) gene.

DNA barcoding and species delimitation of the genus Oxynoemacheilus (Teleostei: Nemacheilidae) in Anatolia.

The DNA barcoding approach was used for the determination of evolutionary relationships and species delimitation of the genus Oxynoemacheilus (Teleostei: Nemacheilidae). The COI barcode region (615 bp amplicon) was used to barcode 444 individuals from 64 morphologically identified species in the genus Oxynoemacheilus and 189 haplotypes were identified. The average of the interspecific p distance (9.59%) was about 21-fold higher than the average intraspecific distance (0.44%). A general genetic threshold of 1.46% sequence divergence was defined for species delimitation. The multiple species delimitation methods (BCM, GMYC, bPTP and TCS) revealed a total of 62 molecular operational taxonomic units for 64 morphospecies with a new loach species from the BuyukMelen River. Neighbour-joining, maximum likelihood and Bayesian inference analyses indicated that all haplotypes were clustered into 62 clades, which corresponded to Oxynoemacheilus species, with strong bootstrap support (≥95%). Furthermore, all samples grouped in concurrence with the taxonomic status of the species except for species groups (O. germencicus-O. cinicus-O. mesudae and O. leontinae-O. namiri) that were showed intraspecific overlap in genetic diversity for COI-based barcodes. In conclusion, our analyses indicate that COI-based barcodes provide reliable species discrimination. Therefore, we currently recommend COI barcodes as the suitable barcode for genus Oxynoemacheilus.

emGarra/em emorontesi/em, a new species from the Orontes River drainage (Teleostei: Cyprinidae).

Garra orontesi, new species, is described from the Orontes River drainage in the eastern Mediterranean Sea basin in Turkey and Syria. It is distinguished from its congeners in the Mediterranean Sea basin and adjacent Mesopotamia by possessing 17-21 gill rakers on the lower part of the first gill arch, the pelvic-fin origin usually below the second branched dorsal-fin ray, 8½ branched dorsal-fin rays, usually 2-3 scales between the tip of the pectoral and pelvic-fin origins, and no tubercles behind the upper posterior eye margin. It is also distinguished by a minimum K2P distance of 2.7% in its COI barcode region against G. rufa, and 3.9% against the geographically adjacent G. turcica.

Alburnus nasreddini, a synonym of A. escherichii (Teleostei: Leuciscidae).

Alburnus nasreddini described from Lake Eber in Central Anatolia is a junior synonym of A. escherichii, a widespread species in adjacent Sakarya River drainage. We found no morphological characters to distinguish Alburnus nasreddini from A. escherichii and both are poorly distinguished on a molecular level also.

Oxynoemacheilus cilicicus, a new nemacheilid loach from the Göksu River in southern Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus cilicicus, new species, is described from the Göksu, Seyhan and Ceyhan rivers in southern Turkey. It is distinguished from other Oxynoemacheilus species in the Eastern Mediterranean Sea basin by possession of an incomplete lateral line, terminating before the vertical of the dorsal-fin origin or slightly behind the dorsal-fin base, a deeply emarginate caudal fin, no suborbital groove in male individuals, and a series of dark-brown bars on the flank not interrupted along the lateral line. Molecular data suggest that Oxynoemacheilus cilicicus is characterised by 22 variable nucleotide substitutions and a minimum K2P distance of 4.09% with O. panthera in the mtDNA COI barcode region.

The westernmost known population of Paracobitis (Teleostei, Nemacheilidae), with the description of a new species from the Euphrates River in southern Anatolia.

Paracobitis salihae, new species, from the Göksu River in the western upper Euphrates drainage, is distinguished from other Paracobitis species by possessing a truncate caudal-fin, and a dark-brown vermiculate or marbled colour pattern. It is also characterised by 19 variable nucleotide substitutions, three diagnostic nucleotides and 3.6% minimum K2P distance compared to geographically adjacent and related P. zabgawraensis. Paracobitis salihae might be Critically Endangered and is threatened by dam constructions.

Molecular systematics and phylogeography of the genus Alburnus Rafinesque, 1820 (Teleostei, Leuciscidae) in Turkey.

In this study, the phylogeny of Alburnus genus distributed in Turkish freshwaters was performed by analyzing mitochondrial cyt b gene (1141 bp) and COI gene (1551 bp) sequences from 1172 samples representing 112 populations of 24 species through their geographical distribution. According to our findings, 20 valid species are distributed in Turkey of which 18 have already been known. While six Alburnus species (A. battalgilae, A. istanbulensis, A. carinatus, A. schischkovi, A. nasreddini ve A. adanensis) have been synonomized, two new species (Alburnus sp.1 and Alburnus sp.2) from Dicle River and Çapraz Stream/Susurluk River have been identified. Extinct species such as A. akili and A. nicaeensis have not been observed in situ. Phylogenetic tree topologies and haplotype network of the 119 cyt b and 80 COI haplotypes detected in Alburnus species have indicated a consensus tree topology containing twenty lineages, each of corresponding to one species, and three Alburnus haplogroups corresponding to the geographical origins: Eastern Anatolia (I), Mediterranean (2) and Western & Northern Anatolia (3). The results indicate that the divergence between those haplogroups may have occurred during the Middle Miocene-Middle Pleistocene periods (from 14.9 to 5.29 million years).

A new species of trout from the northern drainages of Euphrates River, Turkey (Salmoniformes: Salmonidae).

Salmo fahrettini, a new species, is distributed in the northern tributaries of the Euphrates River. It differs from other Salmo species in adjacent waters by a combination of the following characters: a greyish body; one black spot behind the eye and on the cheek; three to six black spots on the opercle; numerous black spots on the back (missing on the predorsal area), flank and middle part of body, surrounded by a roundish white ring; red spots in the median part of the body, surrounded by a roundish white ring; short and narrow maxilla; increase in the number of black and red spots with an increase in size; adipose fin medium size, no or rarely one red spot at its posterior edge; 109-116 lateral line scales; 27-30 scale rows between dorsal-fin origin and lateral line; 20-23 scale rows between the lateral line and anal-fin origin; maxilla length 8.8-10.0% standard length in males, 8.8-9.6 in females.

Phylogeny and phylogeography of the genus Alburnoides (Teleostei, Cyprinidae) in Turkey based on mitochondrial DNA sequences.

Turkey has a rich freshwater biodiversity in terms of Cyprinid genus in respect to its geographical location. To elucidate the phylogeny of the Alburnoides genus, one of these genera, genetic data for the cytochrome b gene (1141 bp) was generated for 445 samples collected at 42 sampling sites across their geographical distribution. A total of 54 mitochondrial haplotypes identified were distrubuted among distinct twelve species that did not share haplotypes with each other. Pairwise sequence divergence among these species range from 1.37% (A. emineae and A. velioglui) and 10.99% (A. manyasensis and A. smyrnae). A new potential species in the River Dirgine that run into the Black Sea Basin was separated from the most closed known species with mean 6.3%. Network analysis and phylogenetic analysis indicated that all haplotypes were clustered into two major clades, which corresponded to twenty-three Alburnoides lineages, with moderate-high bootstrap supports and mutational steps, respectively. Application of a molecular clock to a Bayesian phylogeny indicates that Alburnoides diversified under the paleogeographic conditions such as tectonic uplift and faulting Miocene aged as well as climatic oscillation and sea-level fluctuations during late Miocene-middle Pleistocene. The genetic results of the present study indicated the inter-specific distance of cyt b gene sequences followed the ideal results for species identification and phylogeny of Turkish spirlins.

Comments on the holotype of Alburnus kurui Mangit Yerli 2018 and re-description of A. carianorum Freyhof, Kaya, Bayçelebi, Geiger Turan, 2019 (Teleostei: Leuciscidae).

Article 16.4. of the International Code for Zoological Nomenclature (ICZN, 1999) requires that the fixation of name-bearing types for a new species to be explicit: "Every new specific and subspecific name published after 1999, except a new replacement name…, must be accompanied in the original publication 16.4.1. by the explicit fixation of a holotype,…..and 16.4.2. where the holotype or syntypes are extant specimens, by a statement of intent that they will be (or are) deposited in a collection and a statement indicating the name and location of that collection." That means that for species described after 1999, the holotype must be finally deposited in a collection and it is obligatory to indicate the name of the collection and where it is located.

Oxynoemacheilus cemali, a new species of stone loach (Teleostei: Nemacheilidae) from the Çoruh River drainage, Turkey.

Oxynoemacheilus cemali sp. nov. is described from the Çoruh River drainage in the eastern Black Sea basin. One molecular marker (coI), 25 morphometric and four meristic characters were analysed. Oxynoemacheilus cemali is distinguished from O. kosswigi, O. banarescui, O. samanticus and O. angorae in the Black Sea basin by having a suborbital groove in males, an axillary lobe at the pelvic-fin base, no dorsal adipose crest on the caudal peduncle, a slightly-forked caudal fin and 7-15 dark grey dorsal saddles. Morever, Oxynoemacheilus cemali is distinguished by commonly having 9-15 irregularly-shaped dark-grey bars on the flank posterior to the dorsal-fin origin or, rarely having a mottled pattern or 4-6 irregularly shaped dark-grey bars on the flank posterior to the dorsal-fin origin. Oxynoemacheilus cemali is also distinguished from the closely related species O. araxensis and O. cyri, distributed outside the Black Sea basin, by having 15 and 31 diagnostic nucleotide substitutions in the coI barcode region, respectively.

Redescription of Garra turcica from southern Anatolia (Teleostei: Cyprinidae).

Garra turcica, from the rivers Kizil, Seyhan, Ceyhan and Arsuz, is re-diagnosed and re-described. The species was treated as a synonym of G. rufa but molecular data strongly suggest that G. turcica represent an own species. It is distinguished from G. rufa by being more slender bodied, having a blunt snout and usually a short rostral cap. Based on COI sequence data, G. turcica is closely related to a group of species from the Persian Gulf basin, all having very small distribution areas nested in or adjacent to the range of G. rufa. The closest relatives of G. turcica are G. elegans, G. mondica and G. amirhosseini from which G. turcica differs by having a free posterior edge of the mental disc, the predorsal back covered by scales and the scales on the chest about as large as on the belly as well as by a minimum K2P distance of 2.2% in its COI barcode region.

Redescription of Alburnus kotschyi Steindachner, 1863, with comments on Alburnus sellal adanensis Battalgazi, 1944 (Teleostei: Leuciscidae).

Alburnus kotschyi is re-described and a neotype is designated. It is found in a small isolated coastal stream at Arsuz at the eastern Mediterranean coast as well as in the Ceyhan and Seyhan River drainages in southern Anatolia. Alburnus adanensis, from the Seyhan River, seems not to have been found again since its first description in 1944 and might be extinct.

Generic assignment of Leuciscus kurui Bogutskaya from the upper Tigris drainage, and a replacement name for Alburnus kurui Mangit Yerli (Teleostei: Leuciscidae).

The generic position of Leuciscus kurui Bogutskaya, 1995 is reviewed through a comparison of morphological and molecular characters (COI). The molecular data place L. kurui in Alburnus, close to Alburnus timarensis from the Lake Van basin. Alburnus kurui (Bogutskaya) is distinguished from this species by lacking a ventral keel and possessing both a very low number of gill rakers and midlateral scales. Alburnus selcuklui, from the upper Tigris drainage, cannot be distinguished from the widespread A. sellal and is therefore treated as a synonym of this species. Alburnus kurui Mangit Yerli, 2018 is a junior secondary homonym of A. kurui (Bogutskaya, 1995) and A. carianorum is proposed as its replacement name. Several specimens of Alburnus caeruleus and Alburnus heckeli shared the same haplotypes as some A. sellal and therefore these species cannot always be distinguished by mitochondrial molecular characters. Alburnus caeruleus and A. heckeli are treated as valid species. Other individuals of A. caeruleus have haplotypes very different from A. sellal, and A. heckeli is well distinguished from A. sellal by having more gill rakers. The Lake Van basin as a separate freshwater ecoregion and the treatment of several species of Alburnus in synonymy of A. mento are discussed.

Review of the genus Cobitis in the Middle East, with the description of eight new species (Teleostei: Cobitidae).

The diversity of Cobitis in the Middle East is reviewed, resulting in the recognition of 30 species, of which eight are described herein as new. Two species, C. amphilekta and C. kellei, seem to be extinct. Hypotheses on species-level diversity derived from distance and Poisson tree process analyses of DNA barcode data are tested against morphometric and morphological characters including colour patterns. For species pairs separated by small K2P distances in COI sequence data we follow a practitioner-oriented diagnostic species concept, in which we recognise species only if differentiated morphologically (including by colour pattern). For all 30 species we provide diagnoses and identification keys. Cobitis afifeae, new species, from the Büyük Menderes River drainage in the Aegean Sea basin, is distinguished by having two laminae circularis in the male, a row of blotches below Z4, a small, roundish or comma-shaped black spot at the upper caudal-fin base, and elevated mental lobes. Cobitis aliyeae, new species, from the lower Seyhan and Ceyhan River drainages, is distinguished by having two laminae circularis in the male, the blotches in Z2 and Z4 anterior to the dorsal-fin origin usually well separated from each other, and the pigmentation in Z1 well distinguished from the pigmentation in Z2. Cobitis anabelae, new species, from the lower Orontes River drainage, is distinguished by having two laminae circularis in the male, the pigmentation in Z2 formed by small, brown spots, always much smaller than blotches in Z3, much smaller than the pupil diameter, Z2 and Z3 well separated, and no pigmentation below Z4. Cobitis erkakanae, new species, from the Gölbasi Lakes, adjacent to the Ceyhan River drainage, is distinguished by having two laminae circularis in the male, no blotches below Z4, the blotches in Z2 and Z4 being horizontally elongated and often fused with adjacent ones, and the caudal fin with 4-6 wide, regularly-shaped, brown bands. Cobitis emrei, new species, from the Lake Sapanca basin is distinguished by having one lamina circularis in the male, a large black spot at the upper caudal-fin base, and Z3 fully covered by very small spots forming a sand-like pattern. Cobitis joergbohleni, new species, from the Sultan marshes in Central Anatolia is distinguished by having two laminae circularis in the male, and the flank colour pattern being completely disorganised, not following the Gambetta zones. Cobitis pirii, new species, from the endorheic Lake Egirdir basin and the Mediterranean Aksu and Köprü Rivers, is distinguished by having two laminae circularis in the male, a simple external part of the suborbital spine and two distinct rows of small blotches in Z4, one along the lateral midline and one distinctly below. Cobitis troasensis, new species, from the Tuzla River drainage, is distinguished by having one lamina circularis in the male and 25-36 small, comma-shaped brown blotches in Z4. A lectotype is designated for Cobitis battalgilae. As First Revisers, priority is given to Cobitis fahireae over C. kurui. Cobitis damlae and C. kurui are treated as synonyms of C. fahireae. Cobitis strumicae and C. taenia are recorded for the first time from Anatolia and C. saniae is newly documented from the Black Sea basin in Georgia. The Poisson tree process analysis of COI data proposed 31 groups, most of which could be distinguished by morphological characters. Cobitis troasensis is described based on morphological data alone.