A new species of Astyanax (Characiformes: Characidae) from Costa Rica and Panama,with a key to the lower Central American species of the genus

Astyanax anai, a new species of characid fish, is described from the Sixaola River basin, eastern Costa Rica–western Panama, Central America. The new species can be distinguished from all other congeners by the following combination of characters: premaxillary teeth 4–5 at the inner series and 4–6 at the outer series; maxillary teeth tricuspid, 2–4; predorsal scale series irregular and incomplete, with an unscaled space behind tip of supraoccipital process and 12–14 scales; lateral line scales 34–39; humeral region with a conspicuous black and rounded to horizontally ovate spot and two diffuse brown and vertically elongate bars (the first through the rounded to horizontally ovate spot, the second 2–4 scales behind the first); body depth 36·6–42·3% of standard length (L_S); midlateral stripe formed by a series of 10–14 anteriorly‐directed dermal herringbone, or chevron‐shaped, marks, most apparent in juveniles and in preserved specimens, extending above the lateral line from the black humeral spot or just behind it (from the second vertical bar) to the caudal peduncle; scale rows from lateral line to base of first dorsal‐fin ray 8–9; scale rows from lateral line to base of pelvic fin 7–8; pre‐anal distance 53·9–61·9% of L_S; total anal‐fin elements 29–33; caudal spot elongated, rhomboid or rectangular, with its anterior margin surpassing the middle of the caudal peduncle, usually reaching the anal‐fin insertion, posteriorly covering 4–7 principal caudal‐fin rays and not extending onto the ventral and dorsal margins of the caudal peduncle, covering 3–5 horizontal scale rows. In order to test the phylogenetic relationships of the new taxon in relation to the other North and Central American species of the genus, a new phylogenetic hypothesis based on a reanalysis of the morphological matrix by Schmitter‐Soto (2016) is proposed. A key to the lower Central American (southern Nicaragua to eastern Panama) species of Astyanax is also provided.     

A new blind loach, <Emphasis Type="Italic">Oreonectes elongatus</Emphasis> sp. nov. (Cypriniformes: Balitoridae) from Guangxi,China

A new loach, Oreonectes elongatus sp. nov. is described based on collections from Mulun Township, Huanjiang County, Guangxi in China. It is distinguished from its congeners by the combination of the following characters: most elongate body (body depth/SL 8.62–10.68%), blind, a forked caudal fin, obvious adipose dorsal crest and ventral crest; entire body naked and de-pigmented. Although the new species has a similar distribution with O. macrolepis, it can be distinguished by scales (absent in O. elongatus vs. present in O. macrolepis), shape of snout (elongate vs. round), the opposite position of the dorsal and pelvic fins origins (behind vs. front). The new species shares the same possession of dorsal and ventral crests, a forked caudal fin, eyeless, naked body and incomplete lateral line with O. translucens, but can be distinguished from the latter by caudal fin crest (more developed and translucent in O. translucens), longer anterior nostril tube and barbel, extreme of pectoral fin reaching 2/3 of the distance between origin of pectoral and pelvic fins, more vertebrae (4 + 38–39 vs. 4 + 32).     

A new species of Ituglanis representing the southernmost record of the genus,with comments on phylogenetic relationships (Teleostei: Siluriformes: Trichomycteridae)

Ituglanis australis new species, is described from tributaries of the Laguna dos Patos and Río Uruguay, in Brazil and Uruguay. This represents the southernmost record of the genus and the first occurrence of a species of Ituglanis in those systems. It is distinguished from all its congeners, except Ituglanis parahybae and Ituglanis cahyensis, by its body pigmentation with three well‐defined dark brown stripes running along each flank. Ituglanis australis differs from I. parahybae and I. cahyensis in the pectoral‐ and pelvic‐fin ray counts, the pattern of the cephalic laterosensory system and the number of dorsal‐fin basal radials. The new species, as well as several other examined congeners, has the levator internus IV muscle attached to the dorsal face of the posttemporo‐supracleithrum; a condition that corroborates the inclusion of Ituglanis into a large trichomycterine clade that also includes Bullockia, Hatcheria, Scleronema and several species of Trichomycterus. Previous proposals of the affinities within Ituglanis are reviewed and, despite some advances, the phylogenetic relationships among species of the genus remain largely unknown.     

Revision of Iquius nipponicus Jordan 1919 (Teleostei: Cyprinidae) from the Miocene of Iki Island, Nagasaki, Japan and its phylogenetic position

Iquius nipponicus Jordan 1919 was described on the basis of a single specimen from the Miocene of Iki Island, Nagasaki, Japan, and was tentatively assigned to the family Clupeidae. The holotype consists of the anterior portion of the body (lacking the anal and caudal fins and most of the caudal vertebrae), and is re-examined. The species is re-described based on additional specimens from the type locality. This species possesses an extremely stout third dorsal spine-like fin ray with a smooth posterior edge, an expanded anterior portion of the maxilla covering approximately half of the bone, 13 branched anal fin rays, and 22 abdominal and 16 caudal vertebrae. A phylogenetic study using the character matrix from a previous study suggests that the species forms a clade with xenocyprinins, but it differs from xenocyprinins in the form of the maxilla and the dentary and the numbers of branched anal fin rays and vertebrae. The present study concludes that the genus Iquius does not belong to the family Clupeidae. Iquius is a distinct and valid genus that is closely related to cultrins and xenocyprinins of the family Cyprinidae.     

A new genus, Leptomelanosoma, for the polynemid fish previously known as Polydactylus indicus (Shaw, 1804) and a redescription of the species

A new genus, Leptomelanosoma, is proposed for the polynemid fish, Polydactylus indicus (Shaw, 1804). The genus differs from all other genera in the family Polynemidae by the following combination of characters: anterior one-third of lower jaw with small teeth extending onto lateral surface, adjacent portion of lip poorly developed; ethmoid not covered dorsally by frontals; sphenotics visible dorsally between anterior margins of parietal and pterotic; upper and lower caudal fin lobes very long, filamentous; swimbladder with many appendages inserted into lateral walls of abdominal cavity; grayish-black body. The type species, Polydactylus indicus, is redescribed as Leptomelanosoma indicum. Received: September 19, 1999 / Revised: June 9, 2000 / Accepted: July 10, 2000     

A new genus and species of cyprinid fish (Actinopterygii,Cyprinidae) from the Arabian Peninsula,and its phylogenetic and zoogeographic affinities

Arabibarbus hadhrami, a new species of cyprinid fish from the Hadhramaut Province of Yemen, is described. It has modally 30 scales (29–32) in the lateral line, the wedge-shaped head is longer (27.8–32.5 % SL) and higher (15.5–18.4 % SL) than in its congeners. The body is slender and laterally flattened. The dorsal fin is high (26.5–32.4 % SL) and well ossified. The pectoral fins (19.9–23.9 % SL) and pelvic fins (16.8–19.8 % SL) are longer than in its congeners. Two closely related species, Arabibarbus arabicus and Arabibarbus grypus are re-described and compared to the new species. Based on morphological and molecular characters the new genus Arabibarbus is erected for these three species. It is characterised by medium to large body size, an ossified, smooth principal dorsal fin ray, eight branched dorsal and five branched anal fin rays, large shield-shaped scales with numerous parallel radii, a lateral line with 29 to 44 scales, pharyngeal teeth that are hooked at their tips, their count being 2.3.5–5.3.2 and the possession of two pairs of barbels. Arabibarbus hadhrami is the type species of the new genus. The phylogenetic position of the new genus is analysed, based on the mitochondrial cytochrome b gene. It is the sister taxon to the genus Carasobarbus Karaman, 1971 and closely related to Mesopotamichthys Karaman, 1971, Pterocapoeta Günther, 1902 and ‘Barbus’ reinii Günther, 1874. Arabibarbus probably colonised the Arabian Peninsula about 4 Ma ago, coming from the Tigris-Euphrates drainage in the East via Wādī ar Rimah/Wādī al Bā?in.     

Nematops nanosquama, a new species of righteye flounder (Pleuronectiformes: Poecilopsettidae) from off the Marquesas Islands

A new poecilopsettid flounder, Nematops nanosquama, is described from 10 specimens (4 males, 6 females) collected from deep waters (96–650 m) off Hiva Oa, Marquesas Islands. This species is easily separated from the three recognized species of the genus Nematops by having large numbers of dorsal fin rays, anal fin rays, lateral line scales, and vertebrae, five dark transverse broad bands on the body, and a black blotch on the distal area of the pectoral fin. N.nanosquama shows the easternmost record of this genus from the Pacific Ocean.     

Phylogenetic interrelationships,taxonomy, and reductive evolution in the Neotropical electric fish genus Hypopygus (Teleostei,Ostariophysi, Gymnotiformes)

A phylogenetic reconstruction of the Neotropical electric fish genus Hypopygus based on 47 parsimony‐informative morphological characters is presented. A series of synapomorphies support the hypothesis of monophyly of Hypopygus, and partially resolve species‐level relationships within the genus. Hypopygus species are recognized here as miniaturized fishes based on two criteria; first, a derived condition of diminutive body size, and; second, the presence of a suite of reductive morphological characters, including partial or total losses, simplifications, and reductions of the anal‐fin rays, scales, cranial bones, and laterosensory canal system. Reductive characters associated with miniaturization comprise 45% of the total number of characters in the phylogenetic reconstruction of the genus. Miniaturization and reductive morphological evolution in Hypopygus are discussed here in the phylogenetic context. A taxonomic revision of Hypopygus is presented, in which five new species are described, two species previously assigned to the genus are redescribed, and a single known species of Stegostenopos is redescribed and included in Hypopygus as a junior synonym. Distribution maps and a key for all eight valid species of Hypopygus are provided, based on the examination of 5014 catalogued museum specimens. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 1096–1156.     

Phylogeny,evolutionary morphology,and hemipenis descriptions of the Middle American jumping pitvipers (Serpentes: Crotalinae: Atropoides)

The jumping pitvipers, genus Atropoides, occur at low to middle elevations throughout Middle America. Recent molecular phylogenetic analyses have included all six species of Atropoides, but only two studies have found Atropoides to be monophyletic and questions persist about relationships within the A. nummifer complex. In this study, our phylogenetic analyses of morphological data provide strong support for the monophyly of Atropoides and recover relationships within the genus that are mostly congruent with those of recent molecular studies, further supporting the evolutionary and biogeographic hypotheses proposed in those studies. Our analyses find support for a sister relationship between A. picadoi and the other Atropoides species and an A. occiduus–A. indomitus clade sister to an A. nummifer–A. mexicanus–A. olmec clade. Within the A. nummifer complex, we find A. mexicanus and A. olmec to be sister species to the exclusion of A. nummifer. We include morphological synapomorphies to support each clade within Atropoides and describe and illustrate the hemipenes of each species. In addition, we discuss the importance of morphological phylogenetics and the functionality and limitations of hemipenial data in systematics.     

<Emphasis Type="Italic">Erromyzon damingshanensis</Emphasis>, a new sucker loach (Teleostei: Cypriniformes: Gastromyzontidae) from the Pearl River drainage of Guangxi,China

Erromyzon damingshanensis, a new sucker loach is described from the Pearl River drainage in Guangxi, China. The new species Erromyzon damingshanensis is distinguished from the other species of the genus in having a crescentic median lobe of the rostral fold, rostral barbels shorter than rostral fold; postlabial groove broadly interrupted medially, seven branched dorsal fin rays, 16 branched pectoral fin rays, lateral line scales 88–95, caudal peduncle depth larger than its length; body with 12 irregular bars on flank, interrupted on dorsum.     

Multigene phylogeny of Synura (Synurophyceae) and descriptions of four new species based on morphological and DNA evidence

We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new sectional ranks; Synura, Peterseniae, Curtispinae (presence of body scales with slender spines, tubular scales and caudal scales). We further propose four new species based on phylogenetic analyses and unique scale characters: S. longitubularis sp. nov., S. sungminbooi sp. nov., S. soroconopea sp. nov. and S. lanceolata sp. nov. Lastly, we propose a new genus name, Neotessella, to replace the invalid use of the name Tessellaria.     

Ptolemeba n. gen., a Novel Genus of Hartmannellid Amoebae (Tubulinea,Amoebozoa); with an Emphasis on the Taxonomy of Saccamoeba

Hartmannellid amoebae are an unnatural assemblage of amoeboid organisms that are morphologically difficult to discern from one another. In molecular phylogenetic trees of the nuclear‐encoded small subunit rDNA, they occupy at least five lineages within Tubulinea, a well‐supported clade in Amoebozoa. The polyphyletic nature of the hartmannellids has led to many taxonomic problems, in particular paraphyletic genera. Recent taxonomic revisions have alleviated some of the problems. However, the genus Saccamoeba is paraphyletic and is still in need of revision as it currently occupies two distinct lineages. Here, we report a new clade on the tree of Tubulinea, which we infer represents a novel genus that we name Ptolemeba n. gen. This genus subsumes a clade of hartmannellid amoebae that were previously considered in the genus Saccamoeba, but whose mitochondrial morphology is distinct from Saccamoeba. In accordance with previous research, we formalize the clade as distinct from Saccamoeba. Transmission electron microscopy of our isolates illustrate that both molecularly discrete species can be further differentiated by their unique mitochondrial cristal morphology.     

Phylogeny and character evolution in the Indo-Pacific genus Ctenogobiops (Gobiiformes: Gobiidae)

Ctenogobiops is a genus of Indo-Pacific gobies that form obligate, mutualistic associations with shrimp in the genus Alpheus. This study provides a molecular phylogenetic analysis of eight Ctenogobiops species: C. aurocingulus, C. crocineus, C. feroculus, C. formosa, C. maculosus, C. mitodes, C. tangaroai, and C. tongaensis. We recover two clades within the genus, one consisting of C. feroculus and C. aurocingulus, the second including the remaining species arrayed as follows: (C. tongaensis (C. mitodes (C. formosa (C. maculosus (C. crocineus, C. tangaroai))))). Recovery of C. maculosus and C. crocineus as distinct taxa suggests that these species are not synonymous, although sampling in this study is limited. Species of Ctenogobiops are morphologically very similar to each other, with generally consistent meristic character states present throughout the genus. Recognition of species is based primarily on slight variations in color pattern, shape of the dorsal fin, and size of the gill opening. Comparison of our specimens of C. mitodes with accounts of C. pomastictus confirms that color pattern variations and lateral scale counts are more reliable indicators of species identity than relative dorsal fin spine length, particularly for smaller specimens. We evaluate the distribution of morphological characters in the context of the new phylogenetic hypothesis, and provide a summary of distinguishing characters for Ctenogobiops species. In this case, as in other instances of diverse reef-dwelling fish taxa, molecular data are ideal for inferring phylogenetic relationships, whereas morphological data remain the most expedient way to identify species.     

A new species of electric knifefish,genus Compsaraia (Gymnotiformes: Apteronotidae) from the Amazon River,with extreme sexual dimorphism in snout and jaw length

Abstract

A new species of the neotropical electric fish genus Compsaraia is described from the western Amazon of Peru and Brazil. Compsaraia samueli is distinguishable from all other apteronotids by sexual dimorphism in which mature males exhibit extreme elongation and slenderness of the snout and jaws. Compsaraia samueli is readily distinguishable from its only congener, C. compsa, by more caudal‐fin rays (17–18 vs. 13–16), a shorter caudal peduncle (mean length 9% vs. 34% body length to end of anal fin), a less tapering body shape in lateral profile (mean ratio of body depth at origins of anal fin and dorsal organ 93% vs. 75%), and a smaller maximum adult body size (230 vs. 305 mm). The genus Compsaraia is readily separated from other apteronotids by a pale antorbital stripe and a pale L‐shaped patch over the supra‐temporal canal. The phylogenetic position of C. samueliis estimated by inclusion in a previously published data matrixof osteological and other morphological characters. Comparisons of the cranial bones in apteronotids shows the derived morphology of C. samueli to be a composite of three developmentally and phylogenetically discrete characters: (1) positive allometric growth before sexual maturity in both sexes of the pre‐orbital region of the neurocranium, (2) positive allometric growth of the (oral) jaws, and (3) secondary sexual dimorphism of snout and jaw morphology. The genus Compsaraia represents one of at least three phylogenetically independent cases of snout elongation and one of at least four cases of jaw elongation within the Apteronotidae. Compsaraia samueli also represents one of at least four cases of secondary sexual dimorphism in snout and jaw length within the Apteronotidae. The phylogenetic distribution of snout and jaw characters within the Apteronotidae suggests the influence of both sexual and trophic functional influences on the evolution of head morphology.     

Molecular and morphological studies of Paecilomyces sinensis reveal a new clade in clavicipitaceous fungi and its new systematic position

The type materials of Paecilomyces sinensis, including herbarium specimen and ex-type strain, were re-examined to clarify its relationships with other species. Morphological observations on the strain grown in various culture media revealed that the fungus was morphologically related to Polycephalomyces, since it produced conidial mass and lanceolate or narrowly lageniform phialides. Six genes, including ITS, nrSSU, nrLSU, tef1, rpb1 and rpb2, were amplified from the type materials and used in phylogenetic analyses to determine the systematic position of the fungus in the framework of clavicipitaceous fungi. The results place P. sinensis with Polycephalomyces formosus, the type species of Polycephalomyces, and Cordyceps ramosopulvinata forming a clade unaffiliated with the known families of clavicipitaceous fungi. Based on both morphological and molecular data, a new combination, Polycephalomyces sinensis, is proposed for Paecilomyces sinensis. The new clade found in this study is designated as Polycephalomyces clade and expands the phylogenetic diversity for clavicipitaceous fungi. The teleomorph–anamorph connection between Berkelella and Polycephalomyces previously conceived cannot be retained as the type species of Polycephalomyces, P. formosus, is closely linked to species of Cordyceps s.l. in the new clade.     

Evolutionary trends in the columnar cactus genus Eulychnia (Cactaceae) based on molecular phylogenetics,morphology, distribution,and habitat

Populations of the columnar cactus genus Eulychnia (Cactaceae) are an iconic sight in the Chilean Atacama Desert. The most recent taxonomic treatment of the genus suggested to accept up to seven taxa at species level based on morphological data. To date, species boundaries and infrageneric relationships in Eulychnia have not been investigated using a molecular approach. In this study, sequence data were generated for six chloroplast markers (rpl32-trnL, trnH-psbA, trnL-trnF, trnQ-rps16, trnS-trnG, and ycf1) for the seven species. Where possible, samples were collected from the south and north of the distribution range of widely distributed species, as well as plants from two morphologically distinct populations in the Atacama and Coquimbo Regions. Evolutionary trends of morphological characters were investigated using ancestral state reconstruction, and the habitat of the Chilean taxa was taken into account based on latitudinal and altitudinal distribution, precipitation regime, and vegetation zones. Two major clades were retrieved in the molecular phylogenetic hypotheses, a northern clade and a southern clade, which can easily be distinguished morphologically by differences in rib shape and type of the indumentum of the pericarpel and the hypanthium. The only Eulychnia taxon found outside Chile is most commonly accepted as Eulychnia iquiquensis subsp. ritteri. However, its isolated geographic distribution and the fact that this taxon is not most closely related to E. iquiquensis but was retrieved as sister to the rest of the northern clade in our molecular phylogenetic results support the recognition of E. ritteri at species level. Our results also provide some support for the two recently published species, E. chorosensis (previously placed in E. acida s.l.) and E. taltalensis (previously considered to be part of E. breviflora s.l.). The relationships in the southern clade need further study.     

A new snake eel species of the genus Ophichthus (Anguilliformes: Ophichthidae) from the southeast coast of India,Bay of Bengal,with the taxonomic account of Ophichthus chilkensis

A new species of the ophichthid eel of the family Ophichthidae is described based on five specimens collected from the Mudasalodai fish landing center, off Cuddalore coast, southeast coast of India, Bay of Bengal. Ophichthus naevius sp. nov. is distinguished from its congeners by having a unique color pattern: dorsal body with numerous dense dark spots or patches, ventral body pale yellowish green, dorsal-fin origin just before pectoral-fin tip, vertebral formula: 12–14/52–53/134–138, and teeth on jaw uniserial and pointed. The study also reports the range extension and molecular evidence of Ophichthus chilkensis from South India. Molecular analyses were performed for both species, and their phylogenetic relationship suggests that the new species exhibits 10.2% genetic divergence with its congener Ophichthus sangjuensis, followed by Ophichthus brevicaudatus (10.4%), and Ophichthus sp. 1 (11.8%) also forms the closest clade in both Bayesian inference and maximum likelihood (ML) tree. Similarly, according to the topology of the ML tree, the species O. chilkensis forms a clade with Ophichthus sp. 5, Ophichthus remiger, Ophichthus frontalis, Ophichthus sp. 6, and Ophichthus rex, suggesting that it would be the genetically closest congener.