Deep-water, offshore, and new records of Schindler's fishes, Schindleria (Teleostei, Gobiidae), from the Indo-west Pacific collected during the Dana-Expedition, 1928-1930.

Schindleria (Giltay (1934), Schindler's fishes (or infantfishes), is a genus of small (< 22 mm) paedomorphic species of the family Gobiidae which mature extremely fast. These fishes occur from the eastern Pacific (Cocos Islands off Costa Rica, seamounts Nazca and Sala y Gómez) to the southwestern Indian Ocean (southeast Africa). Nevertheless, there is a large gap in the distributional area between the Philippines (western Pacific) and India/Sri Lanka (Central Indian Ocean) which spans nearly 5000 km. We present the first comprehensive documentation of published records of Schindleria together with samples collected during the Dana-Expedition, between 1928 and 1930 at 44 stations from Polynesia to southeast Africa, with 8 records from the western Pacific to the Central Indian Ocean. We present three first records, 18 new records and the southernmost record for the Indian Ocean. Although Schindler's fishes were generally documented from or close to islands and reefs, we present 23 offshore records (at least 30 km distant to a shore or reef) and 27 deep-water records (at least 65 m deep). Records between 320 and 360 km offshore are the most extreme offshore records of Schindleria ever documented. The records from about 500- and 1000-m depths are the deepest ever documented for Schindler's fishes.

European minnows through time: museum collections aid genetic assessment of species introductions in freshwater fishes (Cyprinidae: Phoxinus species complex).

Massive fish introductions have taken place throughout much of the world, mostly over the last 70 years, and present a major threat to the genetic diversity of native fishes. Introductions have been reported for European Phoxinus, a ubiquitous small cyprinid that populates a wide variety of habitats. Species delineation in European Phoxinus has proven difficult with one reason being ranges of distribution that often traverse drainage boundaries. The present study combines recent samples with museum samples to better understand the current distribution of Phoxinus species and their distributions prior to the massive introductions of fishes in Europe, and to evaluate the use of museum specimens for species distribution studies. For these purposes, genetic lineages from sites collected prior to 1900 (n = 14), and between 1900 and 1950 (n = 8), were analysed using two mitochondrial and nuclear markers. Although possible fish introductions were detected, our results show that the distribution of genetic lineages of museum samples is comparable to that of the extant lineages of European Phoxinus present in those areas. These observations suggest that in the studied ranges the distribution of Phoxinus lineages has been driven by natural processes.

Redescription of the paedomorphic goby Schindleria nigropunctata Fricke br />amp; El-Regal 2017 (Teleostei: Gobiidae) from the Red Sea.

Schindler's fishes (Schindleria) are extremely paedomorphic and only a few morphological characters are suitable for species delimitation of these tiny fishes. Three of these key morphological characters, the (i) origin of the dorsal fin relative to the anal fin, (ii) number of vertebrae and (iii) coloration, need reinterpretation in a recently described species, Schindleria nigropunctata. To avoid nomenclatorial problems S. nigropunctata is redescribed from the type material. This species is characterized by 16-17 dorsal fin rays, 16 pectoral fin rays, origin of the anal fin ventral to the 8th dorsal fin ray, 37-38 myomeres, a uniform greyish-white colored body (preserved) and a trunk without obvious pigmentation (no black pigment spots). The eyes are dark grey with a silvery cornea. Dorsally on the cornea are blackish melanophores arranged in a sickle-shaped pattern.

New data on the western Balkan leuciscids Alburnoides and Alburnus (Teleostei, Leuciscidae) from the Vjosa River, Albania.

The first voucher-confirmed record of Alburnus scoranza and the first morphological description of Alburnoides for the Vjosa River system in Albania are reported with a brief discussion of the diagnostic morphological traits and taxonomic assignment of both species.

Within-generation and transgenerational plasticity of mate choice in oceanic stickleback under climate change.

Plasticity, both within and across generations, can shape sexual traits involved in mate choice and reproductive success, and thus direct measures of fitness. Especially, transgenerational plasticity (TGP), where parental environment influences offspring plasticity in future environments, could compensate for otherwise negative effects of environmental change on offspring sexual traits. We conducted a mate choice experiment using stickleback ( Gasterosteus aculeatus) with different thermal histories (ambient 17°C or elevated 21°C) within and across generations under simulated ocean warming using outdoor mesocosms. Parentage analysis of egg clutches revealed that maternal developmental temperature and reproductive (mesocosm) environment affected egg size, with females that developed at 17°C laying smaller eggs in 21°C mesocosms, likely owing to metabolic costs at elevated temperature. Paternal developmental temperature interacted with the reproductive environment to influence mating success, particularly under simulated ocean warming, with males that developed at 21°C showing lower overall mating success compared with 17°C males, but higher mating success in 21°C mesocosms. Furthermore, mating success of males was influenced by the interaction between F1 developmental temperature and F0 parent acclimation temperature, demonstrating the potential role of both TGP and within-generation plasticity in shaping traits involved in sexual selection and mate choice, potentially facilitating rapid responses to environmental change. This article is part of the theme issue 'The role of plasticity in phenotypic adaptation to rapid environmental change'.

Two new deep-water species of the genus Thorogobius (Teleostei: Gobiidae) from the upper continental slope of the Eastern Central Atlantic.

Two new gobiid species, Thorogobius alvheimi sp. nov. and Thorogobius laureatus sp. nov. (Teleostei: Gobiiformes: Gobiidae), are described from the outer continental shelf and upper slope of the Eastern Central Atlantic off Angola, Ghana and São Tomé and Príncipe. The specimens were trawled from depths between 57 and 208 m. The new species are most similar to Thorogobius angolensis. Thorogobius alvheimi sp. nov. is distinguished from its congeners in the combination of following characters. Fins: first dorsal fin with the second and third spines distinctly elongated; pectoral fin ray count 20-21; pelvic disc complete and short with well-developed anterior membrane (frenum) and pointed lateral lobes. Scales: nape and predorsal area naked; no scales on opercle; scales in longitudinal series 27-31. Pattern of free neuromasts: supratemporal rows tr and trp developed, extending transversally between pores H and K; longitudinal row g short, not passing row m posteriorly and distinctly distant from row h; infraorbital row 6 long, ventrally extending to lower margin of preopercle, its ventral section 6i originating anterior to its dorsal section 6s; posterior lateral row h reaching anteriorly above posterior third of opercle. Coloration: body uniformly pale fawn and brown; margin of scale pockets dark brown pigmented, yielding a reticulated pattern; pale spots on nape and predorsal area; caudal fin uniformly dusky greyish. Thorogobius laureatus sp. nov. is distinguished from its congeners in the combination of following characters. Fins: first dorsal fin the second and third spines distinctly elongated; pectoral fin ray count 19-22; pelvic disc complete, short, with well-developed anterior membrane (frenum) with pointed lateral lobes. Scales: scales on sides of predorsal area and midline mostly naked; no scales on opercle; scales in longitudinal series 24-27. Pattern of free neuromasts (sensory papillae): supratemporal rows tr and trp developed, extending transversally between pores H and K; longitudinal row g long, passing row m posteriorly and relatively close to row h; infraorbital row 6 long, ventrally extending to lower margin of preopercle, its ventral (6i) and dorsal (6s) originating opposite to each other; posterior lateral rows: row h long, reaching anteriorly above middle of opercle. Coloration: body pale fawn and brownish; margin of scale pockets dark brown pigmented, yielding a reticulated pattern; five brown blotches on flanks in lateral midline from below first dorsal fin to caudal peduncle; caudal fin with six or seven distinct dark vertical bands.

The complete mitochondrial DNA sequence of Pectenocypris sp. (Actinopterygii: Cyprinidae) from Serkap River, Sumatra, Indonesia.

The whole mitochondrial genome of a small cyprinid freshwater fish Pectenocypris sp. collected from Serkap River, Central Sumatra, Indonesia was sequenced. This mitochondrial genome consisted of 16,589 bp and included 37 genes in the same order as in many other vertebrates including the human. Phylogenetic analysis suggested that this taxon clusters with Boraras maculatus among several Rasbora species.

A new species of Schindler's fish (Teleostei: Gobiidae: Schindleria) from the Malay Archipelago (Southeast Asia), with notes on the caudal fin complex of Schindleria.

Schindleria macrodentata sp. nov., a new species of the paedomorphic gobiid fish genus Schindleria, is described from the Malay Archipelago. The two specimens were collected in 1929 during the "Dana Expedition" in the Molucca Sea between Sulawesi and Halmahera islands (00°29'N, 125°54'E) (Indonesia) and in the Sulu Sea close to Panay Island (11°43'N, 121°43'E) (Philippines). The new species is characterized by a slender body (body depth at pectoral fin base 3.6-3.7 % of SL and at anal fin origin 3.9-4.8 % of SL), a long second dorsal fin (first dorsal fin absent) originating distinctly anterior to the origin of the anal fin (predorsal length 61.8-65.2 % of SL and preanal length 71.7-75.8 % of SL), a short tail (from anus to tip of longest caudal fin ray) (22.1 % of SL), 19-20 dorsal fin rays and 10 anal fin rays, first anal fin ray below 9th dorsal fin ray, few large, widely spaced teeth in the upper and the lower jaws (7 on the premaxilla and 6 on the dentary), an elongated pectoral radial plate (length 3.7-4.5 % of SL) and, in the caudal skeleton, a procurrent ray with an additional spiny process at its base. No distinct urogenital papilla and no pigmentation on body are developed. In this study we present three morphological traits until now not considered as diagnostic characters for Schindleria, the shape of the pectoral radial plate, the shape of the last procurrent caudal spine and the shape of the arch formed by the lower jaw. We also discuss the caudal-fin skeleton of Schindleria, a character developing beyond the larval stages. The record of S. macrodentata is the first of the genus Schindleria for Indonesia and, at more than 100 km distant to the next shore, it is the first offshore record of a Schindler's fish.

Corrigendum to «Contrasting morphology with molecular data: an approach to revision of species complexes based on the example of European (Cyprinidae)¼ by Palandacic et al. 2017.

[This corrects the article DOI: 10.1186/s12862-017-1032-x.].

Contrasting morphology with molecular data: an approach to revision of species complexes based on the example of European Phoxinus (Cyprinidae).

BACKGROUND: Molecular taxonomy studies and barcoding projects can provide rapid means of detecting cryptic diversity. Nevertheless, the use of molecular data for species delimitation should be undertaken with caution. Especially the single-gene approaches are linked with certain pitfalls for taxonomical inference. In the present study, recent and historical species descriptions based upon morphology were used as primary species hypotheses, which were then evaluated with molecular data (including in type and historical museum material) to form secondary species hypotheses. As an example of cryptic diversity and taxonomic controversy, the European Phoxinus phoxinus species complex was used. RESULTS: The results of the revision showed that of the fourteen primary species hypotheses, three were rejected, namely P. ketmaieri, P. likai, and P. apollonicus. For three species (P. strandjae, P. strymonicus, P. morella), further investigation with increased data sampling was suggested, while two primary hypotheses, P. bigerri and P. colchicus, were supported as secondary species hypotheses. Finally, six of the primary species hypotheses (P. phoxinus, P. lumaireul, P. karsticus, P. septimanae, P. marsilii and P. csikii) were well supported by mitochondrial but only limitedly corroborated by nuclear data analysis. CONCLUSION: The approach has proven useful for revision of species complexes, and the study can serve as an overview of the Phoxinus genus in Europe, as well as a solid basis for further work.

Morphological divergence of lake and stream Phoxinus of Northern Italy and the Danube basin based on geometric morphometric analysis.

Minnows of the genus Phoxinus are promising candidates to investigate adaptive divergence, as they inhabit both still and running waters of a variety of altitudes and climatic zones in Europe. We used landmark-based geometric morphometric methods to quantify the level of morphological variability in Phoxinus populations from streams and lakes of Northern Italy and the Danube basin. We analyzed body shape differences of populations in the dorsal, lateral, and ventral planes, using a large array of landmarks and semilandmarks. As the species identification of Phoxinus on morphological characters is ambiguous, we used two mitochondrial genes to determine the genetic background of the samples and to ensure we are comparing homogenous groups. We have found significant body shape differences between habitats: Minnow populations inhabiting streams had a deeper body and caudal peduncle and more laterally inserted pectoral fins than minnows inhabiting lakes. We have also found significant body shape differences between genetic groups: Italian minnows had deeper bodies, deeper and shorter caudal peduncles, and a shorter and wider gape than both groups from the Danube. Our results show that the morphology of Phoxinus is highly influenced by habitat and that body shape variation between habitats was within the same range as between genetic groups. These morphological differences are possibly linked to different modes of swimming and foraging in the respective habitats and are likely results of phenotypic plasticity. However, differences in shape and interlandmark distances between the groups suggest that some (though few) morphometric characters might be useful for separating Phoxinus species.

A new species of Satyrichthys (Teleostei: Peristediidae) from the Maldives Archipelago (Indian Ocean).

A new species of the genus Satyrichthys, Satyrichthys kikingeri sp. nov., is described from the Rasdhoo Atoll, Maldives Archipelago. The new species is placed in a group of Satyrichthys with at least three lip barbels and unequal parietal bones. It differs from its congeners in the combination of the following characters: (1) 3/3 lip and 1/0 chin barbels, (2) 15 fin rays in the second dorsal fin, 13 fin rays in the anal fin, (3) 25 bony plates in the dorsal, 29 in the upper lateral and 20 in the lower lateral rows, (4) 21st to 28th bony plates in the upper lateral row with forward directed spines and (5) parietal bones unequal in size on midline. Satyrichthys kikingeri sp. nov. is the first Satyrichthys species reported from the Republic of the Maldives.

Early development of the postcranial skeleton of the pikeperch Sander lucioperca (Teleostei: Percidae) relating to developmental stages and growth.

The early development of the postcranial skeleton (pectoral girdle, pelvic girdle, vertebral column and fins) in pikeperch (Sander lucioperca (L.)) was studied from hatching to days 47 and 43 post fertilization (dpf) at two different rearing temperatures, 15.5 and 18.0°C. Four embryonic and six larval stages were described, ranging from 3.4 ± 0.3 mm to 21.8 ± 2.1 mm in total length. The crucial point in larval development is swimbladder inflation, which enables larvae to swim energy efficiently. Until this time point, only the most essential skeletal elements to enable swimming movements have developed. As the larvae become neutrally buoyant, they grow and differentiate postcranial elements rapidly. Concurrently, swimming performance and foraging success seems to improve. A specific size is correlated with a distinct developmental stage defined by a set of traits that includes the skeletal elements. The developmental sequence of skeletal structures is temperature independent, although growth is slower and the individual developmental stages are reached later at 15.5°C than at 18.0°C.