Polychaos centronucleolus n. sp. – a new terrestrial species of the genus Polychaos (Amoebozoa,Tubulinea) with nontypical nuclear structure

A new species of the “proteus-type” naked amoebae (large cells with discrete tubular pseudopodia) was isolated from tree bark sample of a birch tree in the surrounding of Kislovodsk town, Russia and named Polychaos centronucleolus n. sp. (Amoebozoa, Tubulinea). Amoebae of this species have a filamentous cell coat and a nucleus with a central compact nucleolus. This type of nucleolar organization has not been previously known for the genus Polychaos. A sequence of the 18S rRNA gene of this strain was obtained using whole genome amplification of DNA from the single amoeba cell, followed by NGS sequencing. The analysis of molecular data robustly groups this species with Polychaos annulatum within the family Hartmannellidae. Our results, together with the results of our previous studies, show that the taxonomic assignment of “proteus-type” amoebae species is becoming increasingly complex, and the taxonomic characters that can be used to classify these organisms are becoming more shadowed.     

Thecamoeba astrologa n. sp. – A new species of the genus Thecamoeba (Amoebozoa,Discosea, Thecamoebida) with an unusually polymorphic nuclear structure

Thecamoeba astrologa n. sp. was isolated from a plant litter sample. This species has a complex locomotive morphology, to a certain extent intermediate between the striate and the rugose morphotype. The shape of the actively moving cell is similar to that of striate thecamoebians, such as T. quadrilineata. However, in a slow movement, they can be easily confused with rugose species, like T. similis. Thecamoeba astrologa normally has peripheral asterisk-like nucleoli, which are unique among known thecamoebids. However, the structure of the nucleus is unusually variable during the growth of the culture and in some cases may become almost a vesicular one. The phylogenetic analysis based on the 18S rRNA gene sequence shows that this species belongs to the clade of thecamoebids, consisting of species possessing vesicular nuclei. This finding indicates that the structure of the nucleus derived from a single or few observations (as it usually happens in faunistic or ecological studies) may not be a reliable character of a thecamoebid amoeba. In some species nuclei may be highly polymorphic and dominating nuclear structure may depend on the age of the culture. Nuclei with constantly or temporarily peripheral nucleoli are now known in both major phylogenetic branches of the genus Thecamoeba.     

Karyotypic instability of endoprophase and mitotic cells of Amoeba sp. strain Cont from the “proteus-type” group (Amoebozoa,Euamoebida, Amoebidae)

We performed karyotyping of Amoeba sp. strain Cont. Based on the results of a cytological analysis, we concluded that the chromosome number of Amoeba sp. strain Cont in mitosis was unstable. In all cases they appeared to be hypergaploid (the basic chromosome number is 30), with monosomy of all chromosomes except four shortest ones. The presence of “extrachromosomes” in the nucleus could prolong until the beginning of the anaphase. It was only then that they were ejected from the nucleus and the euploidy (haploidy) was restored. The stage of endoprophase nucleus was revealed in the cell cycle of Amoeba sp. strain Cont. This stage has not yet been found in other amoebae from the “proteus-type” group that had been previously studied (A. proteus strain B and A. borokensis). The maximum number of endoreplication rounds in the strain Cont amoebae nuclear cycle was 4 or 5. The regular extrusion of chromosomes from the nucleus into the cytoplasm occurred in each of the endoreplication rounds. Comparative cytological analysis of A. proteus strain B, A. borokensis and Amoeba sp. strain Cont karyotypes indicated that strain Cont, though rather close to the former two amoebae, is actually a distinct species.     

Thecamoeba cosmophorea n. sp. (Amoebozoa,Discosea, Thecamoebida) — An example of sibling species within the genus Thecamoeba

A new species Thecamoeba cosmophorea n. sp. (Amoebozoa, Discosea, Thecamoebida) was isolated from leaf litter collected in the surroundings of Saint-Petersburg (Russia). This species resembles T. quadrilineata in light-microscopic morphology, but has certain morphological differences and significantly differs in 18S rRNA gene sequence. We performed a direct comparison of this newly isolated species with the Thecamoeba strain isolated from leaf litter in East Siberia (Russia) and identified as T. quadrilineata both at the morphological and the molecular level. There is no type strain of T. quadrilineata, and the type material on this species is represented with the stained slide by F.C. Page that he designated as neotype in 1977. The sequence of the 18S rRNA gene of this species deposited in the GenBank belongs to the isolate identified as T. quadrilineata by Rolf Michel in 1998 and deposited as CCAP 1583/10 strain. Hence we cannot be entirely sure that morphological and molecular data on T. quadrilineata belong to the same amoebae species. The use of molecular data for reliable species differentiation is getting obligate even within the amoebae genus Thecamoeba, which until recently was believed to be among few genera of naked lobose amoebae allowing morphological identification of species.     

Thecamoeba foliovenanda n. sp. (Amoebozoa,Discosea, Thecamoebida) – One more case of sibling species among amoebae of the genus Thecamoeba

Until recently it seemed that amoebae of the genus Thecamoeba can be reliably identified using light-microscopic characters, like the size and shape of the cell, a characteristic pattern of folds and ridges and structure of the nucleus. However, recent molecular studies show the presence of sibling species that can be reliably distinguished based on the gene sequence data only. Here we describe a new terrestrial species, Thecamoeba foliovenanda n. sp. This species is almost identical with Thecamoeba similis in light-microscopy, which has minor differences in the ultrastructure but considerable differences in the SSU rRNA gene sequence. We investigated the light-microscopic data, as well as transmission electron-microscopic images and videorecords on the type strain of T. similis 1583/8 and performed its comparison with the new species. This study further supports the conclusion that species of the genus Thecamoeba nowadays require gene sequencing for reliable identification and species distinction.     

Vannella primoblina n. sp. – an unusual species of the genus Vannella (Amoebozoa,Discosea, Vannellida) with pronounced dorsal ridges and folds

Amoebae of the order Vannellida (Amoebozoa, Discosea) have a fairly recognizable spatulate, fan-shaped or semi-circular outlines and a wide area of frontal hyaloplasm. They can be easily distinguished from the other groups of lobose amoebae even by light microscopy. The dorsal side of these amoebae is usually smooth and rarely bears ridges or folds, which are never numerous or regular. We have isolated an unusual species of vannellid amoebae, called Vannella primoblina n. sp. from a terrestrial substrate. It has well-developed dorsal relief consisting of regularly appearing folds and ridges. This amoeba superficially resembles members of the genus Thecamoeba. However, molecular analysis showed that this strain belongs to the genus Vannella. This finding indicates that dorsal folds may also be a characteristic of some species of vannellid amoebae and probably are a functional detail of the cell morphology rather than an apomorphy of Thecamoebida lineage. Overall outlines of the cell and the presence of the expanded frontal hyaline area remains the most reliable characters used to differentiate vannellid amoebae from other gymnamoebae lineages.     

On Artigasia horridospina n.sp., Longior semialata n.sp., Mentecle magnifica n.sp., Paraxyo ensicrinatus n.sp. (Oxyurida: Hystrignathidae) and Pulchrocephala? pulchrocephala Travassos, 1925 (Oxyurida: Pulchrocephalidae)

Summary Four new species of hystrignathid nematodes are described from the midgut caeca of Passalus unicornus (Coleoptera: Passalidae) from St. Lucia, West Indies. Artigasia horridospina n.sp. is differentiated from A. dispar van Waerebeke, 1973 by virtue of fewer rows of spines in the oesophageal region and in possessing lateral alae, and from A. insignia Travassos & Kloss, 1958 in the extent of the oesophageal spiens and in having the lateral alae commence more anteriorly. The first annule is also much shallower than that of A. insignia. Longior semialata n.sp. is differentiated from L. longicollis Travassos & Kloss, 1958 on body length, b ratio, egg size and the starting point of the lateral alae. Mentecle magnifica n.sp. differs from M. parvus Travassos & Kloss, 1958 in having the spines of the oesophageal region extending much further down the body and in having ridged eggs. It is also longer and relatively thinner. Paraxyo ensicrinatus n.sp. differs from P. monodelpho Travassos & Kloss, 1958 in having a proportionately longer tail. The spines in the oesophageal region also extend considerably further posteriorly than in P. monodelpho.Two types of male associated with the above nematodes are described and illustrated, but not assigned to females. Pulchrocephala? pulchrocephala Travassos, 1925 is redescribed from the gut of the mole-cricket Scapteriscus vicinus.Scanning electron micrographs of four of the described species are given and briefly discussed. ac]19801024     

Vannella samoroda n. sp. (Amoebozoa) — First member of the genus from a continental saline habitat placed in a molecular tree

Vannella samoroda n. sp. (Amoebozoa, Vannellida) was isolated from the mouth of the Malaya Samoroda river flowing into Elton, the largest European hypersaline lake (Russia). Among all rivers of the area, it has the highest salt content (ca. 110‰). Amoebae maintained in seawater medium with ca. 77‰ salts concentration had a set of morphological characters typical of Vannella spp.: rounded, fan-shaped, or spatulate locomotive form, floating form with bent, blunt-ended hyaline pseudopodia, and a cell coat consisting of regularly packed palisade elements and scarce simple filaments. Phylogenetic analyses based on SSU rRNA and cytochrome C oxidase subunit 1 genes show that the amoeba is most closely related to Vannella ebro Smirnov, 2001, but represents a distinct species. The clade of V. ebro and V. samoroda branches among marine species of Vannella. The studied species is the first member of the genus Vannella from a continental saline habitat described using molecular data. Interestingly, it has a broad range of salinity tolerance: cells reproduce above 18‰, while survival of a few cells regularly occurs even in highly diluted Prescott and James medium. The normal culture restores itself when PJ medium is substituted with 77‰ seawater medium even after months of experimental incubation.     

Three new species, Lamellodiscus tubulicornis n. sp., L. magnicornis n. sp. and L. parvicornis n. sp. (Monogenea: Diplectanidae) from Gymnocranius spp. (Lethrinidae: Monotaxinae) off New Caledonia, with the proposal of the new morphological group ‘tubulicornis’ within Lamellodiscus Johnston & Tiegs, 1922

Three new species of Lamellodiscus are described from four (including two undescribed) species of Gymnocranius off New Caledonia, South Pacific. All three species have a similar body anatomy and morphology of the haptoral hard parts and are distinguished on the basis of the male copulatory organ (MCO). Lamellodiscus tubulicornis n. sp. (type-host: G. grandoculis; other host: Gymnocranius sp. B) has an MCO with a tube and horn; L. magnicornis n. sp. (type-host: G. grandoculis; other hosts: G. euanus, Gymnocranius sp. A and Gymnocranius sp. B) has an MCO with a long horn and a membrane; L. parvicornis n. sp. (type-host: G. euanus; other hosts: G. grandoculis and Gymnocranius sp. B) has an MCO with a small horn and a membrane. Lamellodiscus epsilon Yamaguti, 1968 is redescribed based on the type-specimens (from Monotaxis grandoculis off Hawaii). Lamellodiscus sp. is recorded from Gnathodentex aureolineatus off New Caledonia. All these five species have lamellodiscs that exhibit a unique characteristic: the second lamella forms an almost closed circle, in contrast to all other described species of Lamellodiscus in which the second lamella has the form of one or two crescents. Lamellodiscus spp. are usually classified in two groups, the ‘ignoratus’ and ‘elegans’ groups, according to the structure of the lamellodisc; we propose a new ‘tubulicornis’ group for these five species. In addition to their lamellodisc structure, species of the tubulicornis group are also characterised by their egg (elongate in contrast to tetrahedral in the two other groups) and their hosts (monotaxine lethrinids as opposed to mainly sparids). The generic diagnosis of Lamellodiscus given by Amine & Euzet (2005) is amended to include species with elongate eggs.     

Tabanidae (Diptera) of Amazônia XX. description of Tabanus pseudonebulosus n.sp

Tabanus pseudonebulosus, new species, is described based on 217 female specimens and 5 males collected in Venezuela (Guarico, Aguaio, Santa Elena, and Palmarito) and in Brazil (Parcí: Santana do Araguaia, Serra das Andorinhas in S?o Geraldo do Araguaia, Serra Norte Carajás and Gorotire; Amazonas: Canutama; Mato Grosso do Sul: Corumbá), mostly in open vegetation, scrub forest and in rocky environments. Observed intraspecific variation in the specimens is presented and related to collection localities, and morphological differences are diagnosed in relation to the similar species Tabanus nebulosus DeGeer 1776 and T. importunus Wiedemann 1828. Morphometrical data and indices for specimens in different localities are provided. Drawings and photo of the new species are presented.     

Acicularia? weisswasserensis n. sp. and Terquemella? microsphaera n. sp., two new Dasycladales from the Upper Cretaceous (Late Turonian-Santonian) of the Northern Calcareous Alps (Gosau Group, Austria)

Two new dasycladalean algae are described from the Gosau Group of the Northern Calcareous Alps in Austria. The tiny spicules of Acicularia? weisswasserensis n. sp. were found in foraminiferal wacke- to packstones associated with rudist limestones of the Weisswasser locality (Middle Coniacian), Lower Austria. The small globulous Terquemella? microsphaera n. sp. occurs in marls to marly limestones of the Pletzachalm locality (Upper Turonian), Tyrol, and Russbach locality (Upper Santonian), Lower Austria. The Terquemella-Acicularia group requires taxonomic revision; the two forms described herein, however, are clearly distinct from other species, and belong to the smallest representatives of these genera. In addition, Acicularia? aff. magnapora Kuss and morphologically similar forms interpreted as gametophores of unknown larger dasycladales are described.     

Neotropical Monogenoidea. 32. Cacatuocotyle paranaensis n. g., n. sp. (Dactylogyridae,Ancyrocephalinae) from Characidium spp. (Teleostei,Characidae) from the State of Paraná, Brazil

Cacatuocotyle paranaensis n. sp. (Dactylogyridae, Ancyrocephalinae) is described from the gills of the characid fishes Characidium lanei Travassos and C. pterostictum Gomes collected from two streams on the coast of the State of Paraná, Brazil. Cacatuocotyle n. g. is proposed for species possessing a single cephalic lobe (terminal), one pair of head organs, a convex haptor with thickened muscular anterior margins, one anchor-bar complex (ventral), seven pairs of ventral hooks (one pair associated with the anchor shafts; one central pair anterior to the bar; five submarginal bilateral pairs) and a sinistral vaginal aperture.     

Neotropical Monogenoidea. 54. Proposal of Aetheolabes n. g. (Dactylogyrinea: Diplectanidae), with the description of A. goeldiensis n. sp. from the gills of ‘pescada’ Plagioscion sp. (Teleostei: Sciaenidae) in Brazil

Aetheolabes goeldiensis n. g., n. sp. (Diplectanidae) is described from the gills of ‘pescada’ Plagioscion sp. (Sciaenidae) collected from the Baía de Marajó, about 30 km north of Belém, Pará, Brazil. The monotypic Aetheolabes n. g. is characterised, in part, by its type-species having the haptor and haptoral sclerites modified as a clasp for attachment to the gill tissue of its host, the copulatory complex situated far posterior to the intestinal bifurcation near the mid-length of the trunk, the vaginal pore apparently within the genital atrium, the tegument lacking scales, anchors atypical for diplectanids, and by lacking peduncular spines and squamodiscs. A. goeldiensis n. sp. closely resembles Diplectanum umbrinum Tripathi, 1957 from India and China by the haptoral sclerites forming a clasp, but differs from it primarily by the orientation of the reproductive organs and absence of squamodiscs.     

Tabanidae (Diptera) of Amaz?nia XXI. Descriptions of Elephantotus gen. n. and E. tracuateuensis sp. n. (Diachlorini) from the Brazilian coast

Elephantotus, a new genus of Tabanidae from the Amazon coast, Brazil, is described based on a new species E. tracuateuensis. Five females were collected in Pará State, and a male in Maranhão State. Arguments are presented for separating the new genus from Dasybasis, as well as the possibility of its occurrence being related to the nesting sites of coastal birds. The new species is characterized by its large size (x = 2.15 cm, n = 5 females), glabrous eyes, reddish-brown tegument, light brown frontal callus not touching the edges of the eyes, extending up to the vertex that has traces of ocelli, basal plate of the antennal flagellum with obtuse angle, without a tooth or spine, wings hyaline, with brown basal cells, without appendix in the fork of vein R₄₊₅, and genital furca wide with extended flaps.     

Bakkeius moragai n. gen. et n. sp. and Pojmanskia riosae n. gen. et n. sp. (Trematoda: Digenea: Brachylaimoidea) in birds from the Area de Conservación Guanacaste, Costa Rica

We describe 2 new species of leucochloridiid-like brachylaimoid digeneans parasitizing a variety of birds in the Area de Conservación Guanacaste, Costa Rica, each of which we assign to a new genus. According to Pojmanska's (Pojmanska, T. 2002a. Superfamily Brachylaimoidea Joyeux & Foley, 1930. In Keys to the Trematoda, D. I. Gibson, A. Jones, and R. A. Bray [eds.]. CAB International and The Natural History Museum, London, U.K., p. 31-36.) key for the Brachylaimoidea, we are unable to place either species in any family. One species most closely resembles members of Leucochloridium by having well-developed suckers, lacking an esophagus, and having cecal shoulders, gonads at the posterior end, and the genital pore at posterior end of body but differs by having symmetrical testes, a posttesticular ovary, and a terminal genital pore; thus, we propose the genus Bakkeius for it. The second new genus resembles members of Michajlovia by having ventral genital pores but differs by having extracecal uterine loops in the forebody, a cirrus sac containing the pars prostatica and seminal vesicle, and gland cells surrounding the genital pore; thus, we propose Pojmanskia for it. These new genera must currently be treated as incertae sedis according to Pojmanska (op. cit.); however, we feel that future phylogenetic analyses will require emendation of the family diagnosis for Leucochloridiidae to include those taxa with terminal and ventral genital pores and with preovarian testes.