An official website of the United States government
The non-marine diatom flora of the Antarctic Continent includes several endemic taxa recorded over the past 100 years. One of these taxa, Navicula adminensis D.Roberts & McMinn, was described from the Vestfold Hills, East Antarctica. Detailed light and scanning electron microscopy observations have shown that based on its morphological features, the species does not belong to the genus Navicula sensu stricto. To determine the most closely related genera to N. adminensis, the morphological features of Adlafia, Kobayasiella, Envekadea, Stenoneis, Berkeleya, Climaconeis, and Parlibellus were compared with those of N. adminensis. Although each of these genera shows one or more similar features, none of them accommodates the salient morphological characteristics of N. adminensis. Therefore, a new genus, Sabbea gen. nov., is herein described, and Navicula adminensis is formally transferred to the new genus as Sabbea adminensis comb. nov. The genus Sabbea is characterized by uniseriate striae composed of small, rounded areolae occluded externally by individual hymenes, a rather simple raphe structure with straight, short proximal ends and short terminal raphe fissures, open girdle bands with double perforation and a very shallow mantle.
more »
« less
This content will become publicly available on September 1, 2026
The first phylogenetic reconstruction of Nippostrongylinae (Nematoda: Heligmonellidae) reveals 3 new genera, the polyphyletic nature of Carolinensis and Vexillata , and identifies 5 clades with varying associations with mammals
Abstract The Nippostrongylinae is a group of strongylid nematodes that includes species typically associated with coprophagous mammals; in the New World, it is represented by 82 species within 11 genera. Two main morphological features, the synlophe and the caudal bursa, are used to evaluate the characteristics that allow identification and classification of the organisms in the taxon. However, the analysis of these characters often requires a partial or total destruction of specimens and therefore morphological variation is studied in only a very small subset of organisms per species. To evaluate the phylogenetic signal from these characteristics, we use genetic data to reconstruct the first phylogeny for the Nippostrongylinae using nuclear and mitochondrial genes and include representatives of the most common and diverse genera. The reconstructed phylogeny features five distinct clades and allows us to identify three non-monophyletic taxa includingCarolinensis, VexillataandHassalstrongylus. From these,Carolinensis s. l. is divided into four genera includingCarolinensis, Boreostrongylus, Neoboreostrongylusn. gen. andTepalcuaneman. gen.Stunkardionemais resurrected to includeVexillata noviberiaeandHassalstrongylusis divided into two, establishingLovostrongylusn. gen. to include species that are closely related toGuerrerostrongylusandTrichofreitasia. Organisms in these three genera feature a caudal arrangement of type 2-2-1. Furthermore, species inHassalstrongylus sensu strictoare more closely related to species inMalvinemaandStilestrongylus. Our results reveal the existence of an additional unnamed genus and underscore the usefulness of framing morphological characters in a comparative framework. A key for genera from the Americas is proposed.
more »
« less
- Award ID(s):
- 1756397
- PAR ID:
- 10655608
- Publisher / Repository:
- Cambrige.org
- Date Published:
- Journal Name:
- Parasitology
- Volume:
- 152
- Issue:
- 10
- ISSN:
- 0031-1820
- Page Range / eLocation ID:
- 997 to 1017
- Subject(s) / Keyword(s):
- comparative-method Heligmonellidae Lovostrongylus Neoboreostrongylus Tepalcuanema
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
The Peruvian genera of Edrotini (Pimeliinae) are revised. A new genus Pachacamacius Flores & Giraldo gen. nov. with two new species, Pachacamacius aguilari Giraldo & Flores sp. nov. (type species) and Pachacamacius koepckeae Flores & Giraldo sp. nov., is described. Two species originally described in the genus ProhylithusKaszab, 1964 are reassigned to two new monotypic genera: Sechuranus Flores and Giraldo gen. nov. (type species Prohylithus barbatusKaszab, 1964) and Koneus Giraldo and Flores, gen. nov. (type species Prohylithus peruanusKaszab, 1981). This article includes diagnoses for five genera and redescriptions or descriptions, distributional data, habitat records and habitus photographs for six species. A dichotomous key for all 11 Peruvian species of Edrotini, drawings of new species' male genitalic features, and distribution maps are also provided. A discussion of the external morphological characters and male genitalia of the new taxa compared to the genera and species previously described and on endemicity and zoogeography of Peruvian Edrotini is presented.more » « less
-
Since the first phylogenetic study of the order Batrachospermales,Batrachospermumwas shown to be paraphyletic. Subsequently, sections of the genus have been methodically investigated usingDNAsequences and morphology in order to propose new genera and delineate species.BatrachospermumsectionTurfosais the last section with multiple species yet to be examined. New sequence data of specimens from Europe and the United States were combined with the sparse sequence data already available. Phylogenetic analyses usingrbcL andCOI‐5P sequences showed this section to be a well‐supported clade, distinct fromBatrachospermumsectionBatrachospermumand its segregate genera. Section Turfosais raised to the generic rank asPaludicolagen. nov. Substantial genetic variation within the genus was discovered and 12 species are recognized based onDNAsequence data as well as morphological characters and geographic distribution. The following morphological characters were applied to distinguish species: branching pattern (pseudodichotomous or irregular), whorl size (reduced or well developed), primary fascicles (curved or straight), spermatangia origin (primary or secondary fascicles), and carposporophyte arrangement (loose or dense). Previously published species were transferred to the new genus:P. turfosa,P. keratophyta,P. orthosticha,P. phangiae,andP. periploca. Seven new species are proposed as follows:P. groenbladiifrom Europe;P. communis,P. johnhallii, andP. leafensisfrom North America; andP. aquanigra,P. diamantinensis, andP. turfosiformisfrom Brazil. In addition, three unsequenced species in the section,P. bakarensis,P. gombakensis, andP. tapirensis, were transferred to the new genus.more » « less
-
Sabellid species are known to have a broad depth distribution and have been reported from various deep-sea habitats, including chemosynthetic systems. Despite this presence, only two species have been identified from deep water chemosynthetic habitats and only one has been identified to species. When examining hydrocarbon seep systems along the Upper Louisiana Slope in the Gulf of Mexico, we observed an abundant sabellid species new to science. The characters for the collected specimens did not match any existing genus. The description for the new sabellid genus and species are presented, supported by external morphology and DNA sequence data (cytochrome c oxidase I).Seepicola viridiplumigen. nov., sp. nov. are gregarious, facultative hyper-epibionts within the examined methane seep communities and, seemingly, have a blend of morphological features of the generaPerkinsianaandPseudopotamilla. Specimens also have several distinctive characters including the presence of a pair of peristomial chambers between the ventral lappets and parallel lamellae and the short, button-like shape of the radiolar tips. Abundance estimates forS. viridiplumigen. nov., sp. nov. within the seep habitats are also presented.more » « less
-
Thelyphonida Blanchard, 1852, also known as vinegaroons or whip-scorpions, is a small arachnid order with 140 described species contained in a single family, Thelyphonidae Lucas, 1835. Despite being conspicuous and widely distributed across the tropics and subtropics on four continents, knowledge of the order has been slow to advance. Hypoctoninae Pocock, 1899, one of four subfamilies currently recognized and one of two represented in the New World, comprises five genera. Since its inception, Thelyphonellus Pocock, 1894 has remained the only hypoctonine genus occurring in South America, with only four species described prior to the present contribution. The first detailed morphological study and phylogenetic analysis of Thelyphonellus is presented herein. The morphological phylogenetic analysis—the first for Thelyphonida—includes all except one of the previously described species of Thelyphonellus in addition to two new species described herein; the species of Ravilops Víquez and Armas, 2005 (from the Caribbean island of Hispaniola); and the monotypic Old World genus Etienneus Heurtault, 1984 (from West Africa) scored for 45 morphological characters. A single, most parsimonious phylogenetic hypothesis revealed that Thelyphonellus is paraphyletic with respect to Ravilops. The New World Hypoctoninae comprises four clades with disjunct distributions and well supported by a combination of morphological characteristics, on the basis of which four genera, two of which are new, are recognized: Ravilops, with two species, endemic to Hispaniola; Thelyphonellus, herein restricted to Thelyphonellus amazonicus (Butler, 1872) and Thelyphonellus ruschii Weygoldt, 1979, occurring in Guyana, Suriname, French Guiana, and northern Brazil; Wounaan, gen. n., containing Wounaan vanegasae (Giupponi and Vasconcelos, 2008), comb. n. and Wounaan yarigui, sp. n. from Colombia; and Yekuana, gen. n., containing Yekuana venezolensis (Haupt, 2009), comb. n. and Yekuana wanadi, sp. n. from Venezuela. The two new species are described and illustrated. A key to the identification of the Neotropical genera of Hypoctoninae and a map plotting the known distribution of its species are also presented.more » « less
