Pharyngeal Teeth Research Articles

Late Miocene bony fishes from Pocşeşti (Republic of Moldova)

Isolated pharyngeal and jaw teeth of bony fishes, as well as numerous bones of other vertebrates dated by Late Miocene (middle late Sarmatian s.l. = early Tortonian, 9.8 Ma), were found in the alluvial sediments of Pocşeşti site (Republic of Moldova). Six fish taxa were identified and described in the paper; the majority of them (4 species) are representatives of Cyprinidae family. Taxonomic list also includes sturgeons (Acipenseridae gen. et sp. indet.) and pikes ( Esox sp.). Mixed character of fauna, joint presence of freshwater and marine species suggests that the burial of remnants took place in close proximity to large marine basin in river avandelta. Fish assemblage of Pocşeşti shows an affinity to other early Tortonian localities in Europe and reflects paleobiogeographic changes on the territory of Paratethys during the Late Miocene. Keywords: bony fishes, Late Miocene, Sarmatian s.l., MN 10, Pocşeşti, Eastern Europe.

Disappearing Scales in Carps: Re-Visiting Kirpichnikov's Model on the Genetics of Scale Pattern Formation

The body of most fishes is fully covered by scales that typically form tight, partially overlapping rows. While some of the genes controlling the formation and growth of fish scales have been studied, very little is known about the genetic mechanisms regulating scale pattern formation. Although the existence of two genes with two pairs of alleles (S&s and N&n) regulating scale coverage in cyprinids has been predicted by Kirpichnikov and colleagues nearly eighty years ago, their identity was unknown until recently. In 2009, the ‘S’ gene was found to be a paralog of fibroblast growth factor receptor 1, fgfr1a1, while the second gene called ‘N’ has not yet been identified. We re-visited the original model of Kirpichnikov that proposed four major scale pattern types and observed a high degree of variation within the so-called scattered phenotype due to which this group was divided into two sub-types: classical mirror and irregular. We also analyzed the survival rates of offspring groups and found a distinct difference between Asian and European crosses. Whereas nude × nude crosses involving at least one parent of Asian origin or hybrid with Asian parent(s) showed the 25% early lethality predicted by Kirpichnikov (due to the lethality of the NN genotype), those with two Hungarian nude parents did not. We further extended Kirpichnikov's work by correlating changes in phenotype (scale-pattern) to the deformations of fins and losses of pharyngeal teeth. We observed phenotypic changes which were not restricted to nudes, as described by Kirpichnikov, but were also present in mirrors (and presumably in linears as well; not analyzed in detail here). We propose that the gradation of phenotypes observed within the scattered group is caused by a gradually decreasing level of signaling (a dose-dependent effect) probably due to a concerted action of multiple pathways involved in scale formation.

Crenicichla taikyra (Teleostei: Cichlidae), a new species of pike cichlid from the middle rio Paraná, Argentina.

Crenicichla taikyra, new species, is described from the middle río Paraná, Argentina. Crenicichla taikyra is distinguished from the other species of the genus by the following combination of characters: lower pharyngeal tooth plate stout, bearing molariform teeth, ascending arm of premaxilla longer than the dentigerous arm, posterior edge of preoperculum serrated, a well developed suborbital stripe, and absence of scattered dark dots on flanks. Molariform teeth on pharyngeal jaws is a derived character among Crenicichla species, however this character state has appeared several times in unrelated species.

Histological and histochemical investigations of the pharyngeal jaw apparatus of a carp Cirrhinus mrigala

The histological organization and histochemical aspects of the pharyngeal jaw apparatus of the Indian major carp Cirrhinus mrigala are described. The pharyngeal jaw apparatus consists of a lower pharyngeal jaw and a chewing pad. Histochemical analysis reveals that the epithelium covering the lower pharyngeal jaw is mucogenic and is involved in the secretion of different classes of glycoproteins (GPs) including GPs with oxidizable vicinal diols, GPs with O-sulphate esters and GPs with sialic acid residues with and without O-acyl substitution. Characteristically, the epithelium at irregular intervals is differentiated into simple or branched tubular pharyngeal glands, which often extend deep into the sub-epithelial tissues. Copious mucus secretion from pharyngeal glands may be associated with transportation of chewed food particles toward the esophagus. Histochemistry and fluorescence microscopy show that the epithelium covering the chewing pad is keratinized. The keratinized surface of the chewing pad may be considered to serve as an occlusion surface for the lower pharyngeal jaw teeth forming an efficient pharyngeal mill for chewing food materials.

Taxonomic revision of the genus Carasobarbus Karaman, 1971 (Actinopterygii, Cyprinidae).

Representatives of the fish genus Carasobarbus Karaman, 1971 (Actinopterygii: Cyprinidae) from the Middle East and North Africa were previously placed in 14 different genus-group taxa (Barbellion, Barbus, Barynotus, Capoeta, Carasobarbus, Cyclocheilichthys, Kosswigobarbus, Labeobarbus, Luciobarbus, Pseudotor, Puntius, Systomus, Tor and Varicorhinus). The generic assignment of several species changed frequently, necessitating a re-evaluation of their taxonomic status. In this study, the genus Carasobarbus is revised based on comparative morphological examinations of about 1300 preserved specimens from collections of several museums and freshly collected material. The species Carasobarbus apoensis, Carasobarbus canis, Carasobarbus chantrei, Carasobarbus exulatus, Carasobarbus fritschii, Carasobarbus harterti, Carasobarbus kosswigi, Carasobarbus luteus and Carasobarbus sublimus form a monophyletic group that shares the following combination of characters: medium-sized barbels with a smooth last unbranched dorsal-fin ray, nine or 10 branched dorsal-fin rays and six branched anal fin-rays; scales large, shield-shaped, with many parallel radii; the lateral line containing 25 to 39 scales; the pharyngeal teeth hooked, 2.3.5-5.3.2 or 2.3.4-4.3.2; one or two pairs of barbels. The species are described in detail, their taxonomic status is re-evaluated and an identification key is provided. A lectotype of Systomus luteus Heckel, 1843 is designated. Carasobarbus Karaman, 1971, Kosswigobarbus Karaman, 1971, and Pseudotor Karaman, 1971 are subjective synonyms, and acting as First Reviser we gave precedence to the name Carasobarbus.

Unravelling the blood supply to the zebrafish pharyngeal jaws and teeth

We describe the vascular supply to the pharyngeal jaws and teeth in zebrafish, from larval stages to juveniles, using serial high quality semithin sections and 3D reconstructions. We have identified that the arterial blood supply to the last pair of branchial arches, which carries the teeth, issues from the hypobranchial artery. Surprisingly, the arteries supplying the pharyngeal jaws show an asymmetric branching pattern that is modified over ontogeny. Moreover, the blood vessel pattern that serves each jaw can best be described as a sinusoidal cavity encircling the bases of both the functional and replacement teeth. Capillaries branching from this sinusoidal cavity enter the pulp and constitute the intrinsic blood supply to the attached teeth. The role of these blood vessels during tooth development (whether instructive or nutritive) remains to be determined and requires further study. However, we have provided a firm morphological basis that will aid in the interpretation of experiments addressing this question.

Osteology of the prowfish,Zaprora silenus(Cottiformes: Zoarcoidei: Zaproridae)

The prowfish, Zaprora silenus, is the sole member of the family Zaproridae. It is a large, relatively elongate species with a robust head and body, and it feeds primarily on jellyfishes. Although the larvae and juveniles are pelagic, the adults are demersal, and the species is widely distributed from Southern California around the Pacific Rim to Hokkaido, Japan. The stichaeid affinities of this species have long been recognized, and the family is currently placed, along with the Stichaeidae, in the Zoarcoidei. Previous anatomical studies of Zaprora have been based on relatively few specimens from a limited geographic range and have not included cleared and stained (c&s) specimens. Here, we provide a complete description of the osteology of the prowfish, based on a large series of specimens representing a broad ontogenetic range, including a series of c&s specimens. Our results contradict the findings of previous authors in the structure of the pharyngeal teeth, presence of the pelvic girdle, and the placement of the first dorsal pterygiophore. However, we concur with the findings of previous morphological and molecular phylogenetic studies, which indicate that the prowfish is probably most closely related to at least some members of the Stichaeidae.

A new species of genus Acheilognathus, Bleeker, 1895 from the Tien Yen river, Vietnam

Acheilognathus nguyenvanhaoi Nguyen H. D., Tran D. H. & Ta T. T. sp. n. Holotype: MB-HNUE VI.1-F01; female, 51.4 mm SL; Vietnam: Quang Ninh Prov., Tien Yen River at Binh Lieu town; Nguyen Huu Duc et al., 14 March 2011. Paratype: 1 MB-HNUE VI.1-F02, male, 60.5 mm SL. Same data as holotype. Diagnosis: When Acheilognathus nguyenvanhaoi sp. n. is compared with closely related species of Acheilognathus , it is characteristic in the five following traits: a broad and dark longitudinal stripe on body (both sides) running from tip of snout to tip of middle caudal fin rays, not tapering anteriorly vs. a narrower and lighter one running most anteriorly behind operculum to caudal base, tapering anteriorly; pharyngeal teeth (5.1-0.5, vs. 5-5); spiny rays of dorsal and anal fins (III-IV, vs. III) and scales above lateral line (7, vs less than 6). The new species differed from A. meridianus and A. barbatus in number of predorsal scales; from A. meridianus , A. barbatulus and A. melanogaster in number of vertebrae; from A. melanogaster in lenght of barbel; from A. brevicaudatus and A. melanogaster in number of gill rackers on the outer side of the first gill arch and from A. barbatulus and A. melanogaster in proportion between anterior and posterior length of gas-bladder. Description: SL = 3.09-3.13 BD = 4.48-4.62 HL = 1.97-2.02 PDL = 4.05-4.84 LCP = 7.76-8.48 CPD; HL = 2.76-3.05 OD = 2.70-2.76 IOW. Body compressed. Mouth sub-inferior. Barbels present. Dorsal fin with 3-4 non-segmented spiny soft rays and 9 branched rays. Anal fin with 3-4 non-segmented spiny soft rays and 10-11 branched rays. Pectoral fin with one segmented spiny soft ray and 11 branched rays. Pelvic fin with one segmented spiny soft ray and 7 branched rays. Lateral line complete with 36-37 pored scales. Predorsal scales 13-14; Scales around caudal peduncle 14-15; Gill rakers on external side of first gill arch 9; Pharyngeal teeth 5.1-0.5. Vertebrae 37-38. Inserted position of first proximal pterygiophores in the dorsal and anal fins as 10 th -11 th and 18 th , respectively. Colour in preservative: Body yellowish. A board longitudinal dark stripe on body running from the tip of snout to the tip of the middle caudal fin rays, not tapering anteriorly. Distribution: Presently known only from the Tien Yen river, Quang Ninh province, Northern Vietnam at Binh Lieu town. Etymology: Named for Nguyen Van Hao, a Vietnamese ichthyologist.

Mechanics of Pharyngeal Teeth of Black Carp (Mylopharyngodon piceus) Crushing Mollusk Shells

AbstractMollusks such as snail and mussels adopt hard shells to protect their vulnerable bodies. Recent studies on biomaterials have revealed that these shells especially the nacre layers exhibit excellent mechanical properties, inspiring a number of biomimetic endeavors. Nevertheless, in nature, there is a species of fish called Mylopharyngodon piceus or black carp, whose main diet is exactly snails and mussels. Does such unique diet imply that the pharyngeal teeth of black carp, its major masticatory apparatus, are superior to the mollusk shells in mechanical properties? In this paper, structural and mechanical characterizations are conducted on the pharyngeal teeth of black carp, showing that enameloid, the outermost layer of black carp teeth, possesses similar elastic modulus and hardness in comparison to those of the pond snail shells. To shed light on the mechanics underlying the capability of pharyngeal teeth to crush mollusk shells, parametric studies on the geometry of the shells are conducted by means of finite element method. It is found that whether a mollusk shell is crushable or not, for given pharyngeal teeth, depends on the radius (R) and thickness (t) of the shell. A predation map for black carp teeth is constructed by delimiting the t–R plane into three phasic regions corresponding to three possible consequences of the mechanical competition between pharyngeal teeth and shells. It is interesting to notice that all the freshwater shells chosen at random fall in the crushable regime while the seashells do not necessarily. This feature of black carp teeth can be speculated as a result of evolution in response to its freshwater diet.

Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth.

Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth.

Plasma membrane Ca2 + ATPase Atp2b1a regulates bone mineralization in zebrafish

The zebrafish transgenic lines provide a possibility to observe the development of tissues and organs in real time. Using the reporter line for the zebrafish plasma membrane Ca2+ ATPase (SqET4), we detected its expression in the epithelium of pharyngeal teeth and analyzed its role in their calcification and that of cranial bones. atp2b1a's expression in the pharyngeal epithelium is faithfully recapitulated in the SqET4 transgenics by GFP expression. We showed by morpholino knockdown of Atp2b1a translations as well as chemical inhibition of Atp2b1a pump activity using carboxyeosin, that its activity is required to facilitate calcification of the developing pharyngeal teeth by the dental epithelium. Atp2b1a could be required during calcification of endochondral bones, where it acts at two levels: 1) by exporting Ca2+ from ameloblasts, it provides raw material for calcifying the pharyngeal teeth by adjacent odontoblasts; and 2) by regulating terminal differentiation of pharyngeal epithelial cells, including ameloblasts required for tissue hyper-mineralization. atp2b1a's expression in the pharyngeal epithelium is regulated by the homeodomain transcription factor dlx2b.

Morphological adaptations of digestive tract according to food and feeding habits of the broomtail wrasse, Cheilinus lunulatus

The present study deals with the morphological adaptations of digestive tract according to food and feeding habits of the broomtail wrasse, Cheilinus lunulatus. The highest rate of feeding activity was recorded during spring and the lowest during summer. In the older and younger fish, the rates of feeding activity are nearly similar. The fish is mainly carnivorous benthic feeder. This fish plays an important role as a predator of invertebrates of reef fauna. It consumes a wide range of animal food. Molluscs, echinoderms and small fishes were the main food items consumed by these fish. Molluscs increased and echinoderms decreased in the food with the increasing length of the fish. The mouth is relatively large, terminal in position, usually with prominent lips. Jaws are extremely protrusible to make the fish able to get food between branches of coral reef. The jaws teeth are conical canine in shape and composed of outer uni-serial pointed teeth. Two enlarged teeth are present in the front of the upper and lower jaws. They are specialized for catching and holding the prey and preventing its escape out of the buccal cavity. The pharyngeal teeth are molar in shape with blunt or round edge and arranged in two rows, usually 7 - 17 in each row of the floor. The teeth in the roof are developed and haphazard distributed. These molariform teeth are adapted for crushing and grinding of hard body preys. 11 gill rakers are present on the bowshaped gill arch and conical in shape with tapering tips adapted for binding the prey. Oesophagus is a short muscular distensible tube with few number of large mucosal folds adapted for facilitating conduction of food to the stomach. The Jshaped stomach is of the siphon type with large number of small mucosal folds adapted for food retention to be digested. The intestine is a short uncomplicated tube which recognized by the presence of ileo-rectal valve modified to prevent the passage of food particles into the posterior part before intestinal digestion and absorption is completed. It contains very large number of mucosal folds adapted for facilitating lubrication of feces towards the anus.

Нові рештки плітки Rutilus sp. (Cyprinidae: Leuciscinae) із відкладів пізнього міоцену півдня України

A new roach material from Late Miocene of Odesa Pontian Lectostratotype (MN 13), Southern Ukraine is presented. Fragment of pharyngeal bone and isolated teeth are described as Rutilus sp. Presented specimen is characterized by massive ceratobranchiale, thick bulkheads between septum on the cavernous surface, and considerable pharyngeal teeth size. A review on the fossil fish remains of the Rutilus genus from numerous Miocene and Pliocene localities in Europe (Austria, Germany, Spain, Bulgaria and Netherlands) and Asia (Russia, Turkey, Kazakhstan and Armenia) is presented. Isolated pharyngeal teeth similar to those in Rutilus s p., are found in materials from several Late Miocene localities in Ukraine (e.g., Andriivka, Novoukrainka 1). Possibility of identification of the ichthyological material from Bezimenne locality (Late Pliocene, Khaprovian fauna) as R. sp. (contrary to Mylopharyngodon piceus Richardson, 1849) is discussed. General morphological similarity of this taxon to Rutilus frisii (Nordmann, 1840) can testify to their close phylogenetic relation. Keywords: Rutilus , ceratobranchiale, isolated pharyngeal teeth, Pontian Lectostratotype, Late Miocene, Southern Ukraine.

THE DIGESTIVE TRACT DEVELOPMENT OF THE TIGER GROUPER Epinephelus fuscoguttatus LARVAE TREATED WITH THYROXINE HORMONE

Thyroxin administration in tiger grouper larval rearing was conducted to determine its effect on development of digestive tract of the larvae. Newly hatched larvae were treated with 0 mg/L (control), 0.1 mg/L, and 0.2 mg/L of thyroxin for 2 hours in a 30 L tank before were transferred into a 1 m3 rearing tank. Samples were collected daily until 10 DAH and every 3 days until 40 DAH. Development of digestive tract was observed using histological method. For all treatments, the digestive tract was the same on 1 DAH and 2 DAH. The digestive tract of 1 DAH larvae was still closed and still in the form of a simple tube. The mouth, buccopharynx, liver, pancreas, and rectum were found on 2 DAH. On 3 DAH, the esophagus, stomach, intestines, and anus started to develop. At this stage, the digestive tract of larvae treated with and without thyroxin started to become distinguishable. Several goblet cells were noticed in the rectum of the treated larvae but not in the control. Digestive tract developed earlier in treated larvae compared to the control group, such as appearance of tongue, gill raker, fundic, and cardiac stomach development, formation of pharyngeal tooth, and gastric gland. Metamorphosis of larvae into juvenile on treated larvae occurred than that the control larvae earlier.

Prey selection under laboratory conditions by pond-bred Trematocranus placodon (Regan, 1922), a molluscivorous cichlid from Lake Malaŵi

Trematocranus placodon, a predator of freshwater snails in Lake Malaŵi, has been recommended for the control of schistosome intermediate hosts in aquaculture ponds. Fish from Lake Malaŵi were introduced into a pond close to Lilongwe and we attempted to elucidate whether pond-raised F1 retain their ability to consume snails. In laboratory experiments, small fish (70–80 mm total length) preyed only on Bulinus tropicus while fish of the 100–110 mm and the 120–130 mm size classes also chose B. globosus. All three size classes of fish preferred B. tropicus, which was abundant in the pond where fish were raised. Bulinus nyassanus was consumed by the largest fish only. Melanoides tuberculata was not preyed upon, although this species dominates stomach contents of field collected T. placodon. T. placodon is a pharyngeal crusher and comparisons of the size and dentition of the pharyngeal bones revealed some differences between field collected and pond-bred fishes. Although pond-bred fishes are able to crush snails, the development of the pharyngeal teeth should be better controlled by fish diet. A hard diet early in life is a prerequisite for T. placodon to develop molariform teeth. Later once molariform teeth are developed, fish can be transferred to pond conditions for grow-up and snail control.

The Afro–Asian labeonine genus Garra Hamilton, 1822 (Teleostei, Cyprinidae) in the Pliocene of Central Armenia: Palaeoecological and palaeobiogeographical implications

Fossil skeletal remains of the Afro–Asian labeonine genus Garra are described on the basis of more than 300 specimens from the Pliocene diatomites of Jradzor, Central Armenia. Extant species of the genus Garra exhibit a wide distribution ranging from China, South Asia, and Borneo, through Middle East, the Arabian Peninsula, and Africa, where these fishes inhabit a variety of freshwater biotopes. The Pliocene fossils from the Jradzor site provide the first evidence of Garra in the fossil record. The inadequate preservation of the available material did not allow a detailed taxonomic attribution at the species level. Remains of Garra sp. were found associated to a moderately diverse assemblage, which includes also remains of additional freshwater fishes (Capoeta sp., Leuciscus cf. souffia, Leuciscus sp.), amphibians (Pelophylax cf. ridibundus), and large mammals (Rhinocerotidae indet.), as well as of monocotyledon plants. According to the diatom flora, the diatomites of Jradzor can be assigned to the Pliocene and were deposited in a freshwater lacustrine setting that was characterized by high productivity, eutrophic conditions, and standing macrophyte vegetation along the littoral zone. The presence of abundant resorptive pharyngeal teeth suggests that the Pliocene palaeolake of Jradzor was characterized by resident populations of Garra. Extant species of this genus are currently absent in the freshwaters of Armenia. The record of the genus Garra from Jradzor suggests that the Araks–Kura River drainage was connected, at least in part, with the Euphrates and Tigris River drainage during the Pliocene. The extinction of Garra (and other thermophilous taxa) from Araks and Kura River drainage was probably due to Plio-Pleistocene tectonic uplift of the Armenian Highland and consequent progressive climate cooling.

How does an animal work?

Summary A newly established interdisciplinary research institute in Lyon, France, aims to bridge the cultural divides between evolution, development, and physiology, in order to study how animal functions come into being, starting from the genomes, and not limited to traditional model systems. Michael Gross reports.

Retinoic acid expands the evolutionarily reduced dentition of zebrafish

Zebrafish lost anterior teeth during evolution but retain a posterior pharyngeal dentition that requires retinoic acid (RA) cell-cell signaling for its development. The purposes of this study were to test the sufficiency of RA to induce tooth development and to assess its role in evolution. We found that exposure of embryos to exogenous RA induces a dramatic anterior expansion of the number of pharyngeal teeth that later form and shifts anteriorly the expression patterns of genes normally expressed in the posterior tooth-forming region, such as pitx2 and dlx2b. After RA exposure, we also observed a correlation between cartilage malformations and ectopic tooth induction, as well as abnormal cranial neural crest marker gene expression. Additionally, we observed that the RA-induced zebrafish anterior teeth resemble in pattern and number the dentition of fish species that retain anterior pharyngeal teeth such as medaka but that medaka do not express the aldh1a2 RA-synthesizing enzyme in tooth-forming regions. We conclude that RA is sufficient to induce anterior ectopic tooth development in zebrafish where teeth were lost in evolution, potentially by altering neural crest cell development, and that changes in the location of RA synthesis correlate with evolutionary changes in vertebrate dentitions.

F-Spondin/spon1b Expression Patterns in Developing and Adult Zebrafish

F-spondin, an extracellular matrix protein, is an important player in embryonic morphogenesis and CNS development, but its presence and role later in life remains largely unknown. We generated a transgenic zebrafish in which GFP is expressed under the control of the F-spondin (spon1b) promoter, and used it in combination with complementary techniques to undertake a detailed characterization of the expression patterns of F-spondin in developing and adult brain and periphery. We found that F-spondin is often associated with structures forming long neuronal tracts, including retinal ganglion cells, the olfactory bulb, the habenula, and the nucleus of the medial longitudinal fasciculus (nMLF). F-spondin expression coincides with zones of adult neurogenesis and is abundant in CSF-contacting secretory neurons, especially those in the hypothalamus. Use of this new transgenic model also revealed F-spondin expression patterns in the peripheral CNS, notably in enteric neurons, and in peripheral tissues involved in active patterning or proliferation in adults, including the endoskeleton of zebrafish fins and the continuously regenerating pharyngeal teeth. Moreover, patterning of the regenerating caudal fin following fin amputation in adult zebrafish was associated with F-spondin expression in the blastema, a proliferative region critical for tissue reconstitution. Together, these findings suggest major roles for F-spondin in the CNS and periphery of the developing and adult vertebrate.

Two new freshwater fish species of the genus Telestes (Actinopterygii, Cyprinidae) from karst poljes in Eastern Herzegovina and Dubrovnik littoral (Bosnia and Herzegovina and Croatia)

Two new species, Telestes dabar and Telestes miloradi, are described on the basis of morphological comparisons of isolated geographical populations of fishes identified earlier as Telestes metohiensis. A lectotype is designated for Telestes metohiensis, whose range is shown to include waters of Gatačko, Cerničko, and Nevesinjsko poljes in Eastern Herzegovina. Telestes dabar from Dabarsko Polje (Eastern Herzegovina) and Telestes miloradi from Konavosko Polje (south Croatia) share with Telestes metohiensis the following combination of characters that distinguish them from the rest of the genus Telestes: pharyngeal teeth in one row, usually 5–4; preoperculo-mandibular canal not communicating with the infraorbital canal; mouth subterminal, the tip of the mouth cleft on or below the level of the ventral margin of the eye; postcleithrum minute or absent; ventral portion of the trunk with a dark stripe on a pale background; and dorsal portion of trunk uniformly dark and bordered ventrally by a dark midlateral stripe. Telestes dabar and Telestes miloradi are distinguishable from Telestes metohiensis in usually having 8½ branched dorsal-fin rays (vs. usually 7½), 9 or 10 gill rakers (vs. 7–10, usually 8), and the dark stripe on the ventral portion of the trunk below the main pigmented area of the back narrow and usually not reaching posteriorly to the caudal peduncle (vs. dark stripe wide and extending posteriorly to the caudal peduncle). Telestes dabar is distinguished from Telestes miloradi by having scales on most of the body situated close to one another and overlapping in a region behind the pectoral girdle and usually on the caudal peduncle (vs. overlapping scales on most of the body); the lateral line usually incomplete and interrupted, with 24–69, usually 54–65, total scales (vs. lateral line usually complete, with 55–67 total scales); scales above and below the lateral line slightly smaller than lateral-line scales (vs. of about equal size); head width 43–52% HL (vs. 48–58% HL); and lower jaw length 10–12% SL or 36–41% HL (vs. 8–10% SL or 33–38% HL). Telestes miloradi, a very local endemic species,is known only by historical samples. Telestes dabar is an abundant fish in Dabarsko Polje, but its range is critically restricted during the dry season by a few permanent sources. Nothing is known about its occurrence in underground karst waters.