Zootaxa

Pseudagrion microcephalum (Rambur, 1842)—sifting through a putative familiar species, with erection of two new species (Odonata: Coenagrionidae)

MALTE SEEHAUSEN — 2026-05-14

Specimens of the Pseudagrion blue-group allied to P. microcephalum (Rambur, 1842) were studied with special attention to the male caudal appendages and genital ligulae. The males of P. microcephalum are morphologically re-characterised, and the species is considered to have a limited range that includes India, Pakistan, Nepal, Bangladesh, and Sri Lanka. The status of P. siamense Fraser, 1922 is revised and considered a distinct species, with the scientific name removed from synonymity and a neotype designated and described (♂, 7.viii.1972, stream at Ang Kep Nam-Bang Phra environments, South Chon Buri, Thailand, approximately 13.205°N, 100.975°E, G. von Rosen leg., GvRosen no. 1753; deposited at the Zoological State Collection Munich, Germany). Two new species are erected and figured: P. crenatum sp. nov. from Australia (holotype ♂, 2.x.1915, Caboolture, Queensland, Australia, approximately -27.084°N, 152.951°E, R.J. Tillyard leg., no. 14110; deposited at the Forschungsinstitut und Naturmuseum Senckenberg, Frankfurt am Main, Germany); and P. pirata sp. nov. from the Philippine Islands (holotype ♂, 17.i.1992, Barili, Montayupan falls, Cebu Island, Philippines, approximately 10.101°N, 123.535°E, Th. Borromeo Jr. leg., ex. Coll. Roland A. Müller, no. 975694; deposited at the Naturalis Biodiversity Centre Leiden, the Netherlands). The range of P. coarctatum Lieftinck, 1932, a species previously known only from a few records at Jayapura and Sentani Lake in northeastern Indonesian West Papua, is extended to Sulawesi, the Moluccas and the Solomon Islands; the male is morphologically re-characterised and illustrated, and the female described. Photographs of the holotypes of P. microcephalum, P. coarctatum and P. starreanum Lieftinck, 1949 are provided. In addition, P. stainbergerorum Marinov, 2012 stat. nov. is proposed, based on distinct morphological differences from P. microcephalum. A key to males of the Pseudagrion blue-group is provided, including illustrations of the male caudal appendages and partly of the genital ligulae for all species treated. Pseudagrion daponshanensis Zhou & Zhou, 2007 is transferred to the genus Coenagrion.

Description of five new species of Capitellidae (Annelida, Canalipalpata, Capitellida) from the coast of Chile (South America), and re-description of Mediomastus branchiferus Hartmann-Schröder, 1962

ANDREAS BICK — 2026-05-14

During an expedition with the research vessel SONNE in January 2023 eight stations along an oxygen gradient off Chile (36 °S) were sampled to investigate the differences in species composition along the gradient. This study describes all Capitellidae found at these stations at water depths between 56 and 912 metres. A total of five species were found that were previously unknown. These species are Dodecamastus branchiphorus sp. nov., Leiochrides chilensis sp. nov., Mediomastus concepcionensis sp. nov., Notomastus carlvilhelmi sp. nov. and N. friedrichi sp. nov. These species are described, illustrated and compared with all known species of the respective genera. In this context, the observed variability of the features that are considered important for the characterization of genera and species of Capitellidae is also discussed. The distribution of these species in relation to water depth, oxygen content, sediment and temperature is described and discussed. Mediomastus branchiferus Hartmann-Schröder, 1962, currently considered a taxon inquirendum, is described and illustrated on the basis of type material, and can now be recognized as a valid species again based on the presence of branchiae and other specific characteristics. The occurrence of a larval stage (manca) of an unknown Tanaidacea species in the abdomen of Notomastus carlvilhelmi sp. nov., is also illustrated and described.

**On the taxonomy of genus Compsoctena Zeller, 1852 (Lepidoptera: Eriocottidae) from India and Bangladesh, with descriptions of three new species**

MD JAHIR RAYHAN — 2026-05-14

This work deals with the taxonomy of genus Compsoctena from India and Bangladesh, based on fresh material and historical collections housed in the Lepidoptera section of the Zoological Survey of India, Kolkata. Three new species, Compsoctena kushabhadrae sp. nov., C. kamaraji sp. nov. (India), and C. faridahsani sp. nov. (Bangladesh) are described as new. The following new combinations are proposed based on primary types housed in the Natural History Museum, London: Compsoctena accurata (Meyrick, 1922), comb. nov.; Compsoctena autochthonia (Meyrick, 1931) comb. nov.; Compsoctena certatrix (Meyrick, 1916), comb. nov.; Compsoctena coagulata (Meyrick, 1919), comb. nov.; Compsoctena colonica (Meyrick, 1916) comb. nov.; Compsoctena cremata (Meyrick, 1916), comb. nov.; Compsoctena deposita (Meyrick, 1919) comb. nov.; Compsoctena devincta (Meyrick, 1916) comb. nov.; Compsoctena expedita (Meyrick, 1907) comb. nov.; Compsoctena exsecrata (Meyrick, 1937) comb. nov.; Compsoctena gregaria (Meyrick, 1916) comb. nov.; Compsoctena infensa (Meyrick, 1916) comb. nov.; Compsoctena isopeda (Meyrick, 1907) comb. nov.; Compsoctena jactata (Meyrick, 1937) comb. nov.; Compsoctena lignosa (Meyrick, 1917) comb. nov.; Compsoctena meliphaea (Meyrick, 1916) comb. nov.; Compsoctena multiplex (Meyrick, 1917) comb. nov.; Compsoctena nota (Meyrick, 1919) comb. nov.; Compsoctena obtrectans (Meyrick, 1930) comb. nov.; Compsoctena paraclasta (Meyrick, 1922) comb. nov.; Compsoctena phaeogenes (Meyrick, 1919) comb. nov.; Compsoctena pericrossa (Meyrick, 1907) comb. nov.; Compsoctena praecepta (Meyrick, 1919), comb. nov.; Compsoctena ptyalistis (Meyrick, 1937) comb. nov.; Compsoctena semota (Meyrick, 1938) comb. nov.; Compsoctena subacta (Meyrick, 1919) comb. nov.; Compsoctena tylota (Meyrick, 1916) comb. nov., and Compsoctena vorticosa (Meyrick, 1930) comb. nov. Although all these species were originally described under the genus Melasina, their current taxonomic placement is reviewed and discussed in detail. Additionally, three new country records, Compsoctena thwaitesii (Walsingham, 1887), and C. anasactis (Meyrick, 1907) from India, and Compsoctena pulla Sobczyk & Breithaupt, 2023 from Bangladesh are provided. An updated checklist of Compsoctena from India and Bangladesh is given arranging the species into ten species groups based on male wing maculation.

**A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala**

ALEJANDRO VALDEZ-MONDRAGÓN — 2026-05-14

A new species of the spider genus Euagrus Ausserer, 1875 from temperate pine-oak forests in the states of Tlaxcala and Hidalgo, Mexico is described: E. pulque sp. nov. The description of the new species is based on male and female adult specimens. Additionally, Euagrus gus Coyle, 1988 is recorded for the very first time in the state of Tlaxcala. These species have sympatric distributions in La Malinche National Park, Tlaxcala. With this description, the diversity of the genus increases to 23 species, with Mexico harboring the highest diversity with 17 described species.

**A new species of Pseudosmittia Edwards (Diptera, Chironomidae) from Hongjiannao National Nature Reserve, China**

JIAXIN NIE — 2026-05-14

Pseudosmittia hongjiannaoensis Liu, sp. nov. is described and illustrated based on adult males collected from Hongjiannao National Nature Reserve, Shaanxi, China. Morphological identification, DNA barcoding comparison, and mitochondrial genome (mitogenome) assembly were employed to characterize the new species. The mitochondrial COI barcode sequences and mitogenomic data support its distinction from previously known Pseudosmittia species. The minimum interspecific K2P distance between P. hongjiannaoensis Liu, sp. nov., and its closest congener was 15.1%, with an average distance of 23.0%, substantially exceeding the commonly referenced threshold for insect species delimitation. The new species can be distinguished by the unique shape of the inferior volsella and the lack of an anal point. An updated key to the adult males of Pseudosmittia from China is provided. This discovery of the new species enriches the known diversity of the genus in East Asian inland freshwater ecosystems and highlights the ecological significance of the Hongjiannao Lake as a unique wetland habitat.

A new genus of the family Theridiidae Sundevall, 1833 (Araneae: Theridiidae) from Asia, with description of a new species

YUJUN FANG — 2026-05-14

Chrosiothes Simon, 1894 (Spintharinae) is a genus of theridiid spiders including 25 American and three Asian species. A detailed comparation shows that the Asian species differ markedly from American Chrosiothes, instead bearing several synapomorphies of the subfamily Theridiinae Sundevall, 1833, in addition to some unusual apomorphic characteristics. Based on these observations, a new genus, Loricatheridion gen. nov., is established to accommodate the three Asian “Chrosiothes” species, and a new species from Hubei, China that is described herein.

Chitons (Mollusca: Polyplacophora) on manganese nodules from the Clarion-Clipperton Zone and other regions

BORIS I. SIRENKO — 2026-05-14

Two species of chitons Belknapchiton macleani (Sirenko, 2015) and Carinichiton chiversi (Ferreira, 1981) comb. nov. were found on manganese nodules in the Clarion-Clipperton Zone. For the latter species, a new genus Carinichiton gen. nov. is proposed. Features unique to this genus include aspects of the tegmentum sculpture, slits of insertion plates, and radular teeth. Besides the type locality, Carinichiton chiversi has been found in west of Oregon State, west of New Caledonia, and in the Drake Passage. Scanning electron microscope studies have provided new data on the sculpture of the valves, composition and shape of the perinotum spicules and the shape of radular teeth. These new observations provide an opportunity to discuss the likely feeding mode of chitons on manganese nodules. A series of samples with variable sizes also offers new insights to age variability of the valve keel as a feature.

Festucalex bifasciatus, a new pipefish (Teleostei: Syngnathidae) from northern Australia

DAIJIRO YUKI — 2026-05-14

The new pipefish Festucalex bifasciatus sp. nov., described from eight specimens [89.8–152.8 mm standard length (SL)] collected from Western Australia and Queensland, Australia, and most closely resembling F. cinctus (Ramsay 1882) (11 specimens, 48.8–126.8 mm SL) and F. scalaris (Günther 1870) (10 specimens, 45.4–162.7 mm SL), differs from all members of Festucalex in having 19 or 20 trunk rings; 34–38 tail rings; 24–28 dorsal-fin rays; 12–15 pectoral-fin rays; snout length (SnL) 46.4–52.6% of head length (HL); snout depth 17.8–22.7% of SnL; postorbital length 60.0–74.6% of SnL; lateral trunk ridge ending at second or third tail ring; subadults and adults with or without indistinct ridges on pectoral-fin base; principal ridges of last 1 or 2 tail rings with 1–7 knobs or projections; and opercle with 2 white bars (2 pale bars in preserved specimens). The new species was mostly collected by dredge at depths of 9–81 m. Among all congeners, only F. cinctus shares with the new species the presence of knobbed principal tail ridges, and the two taxa have a broadly overlapping distribution in Australian waters, suggesting a close phylogenetic relationship.

**New combination in the genus Brasiloniscus Cardoso, Campos-Filho & Araujo, 2018 (Isopoda: Oniscidea: Pudeoniscidae)**

RICARDO BORJA-ARRIETA — 2026-05-14

**On the first Subandean species of Myrmecium Latreille, 1824 (Araneae, Corinnidae) from the Cordillera del Cóndor, Ecuador**

PEDRO PEÑAHERRERA-R. — 2026-05-14

Henri Tachet (1937–2025): In recognition of his contribution to freshwater macroinvertebrate taxonomy and ecology

MAXENCE FORCELLINI — 2026-05-14

Finlaya albipes Giles, 1904, an erroneous nomen dubium in Orthopodomyia Theobald, 1904 (Diptera: Culicidae)

C. LORNA CULVERWELL — 2026-05-14

Culex guttatus Curtis, 1835, a mistaken synonym of Dahliana geniculata (Olivier, 1791), alt. Aedes geniculatus (Diptera: Culicidae), with a note on species names attributed to Johann Wilhelm Meigen

C. LORNA CULVERWELL — 2026-05-14