We describe the second- and third instar larvae of the diving beetle Rhantaticus congestus (Klug, 1833), including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, terminal abdominal segment and urogomphi in order to discover useful characters for distinguishing Rhantaticus Sharp, 1882 larvae from those of other known Aciliini (Coleoptera: Dytiscidae: Dytiscinae). A parsimony analysis based on 94 larval characteristics of nine Aciliini species in five genera (Acilius Leach, 1817, Graphoderus Dejean, 1833, Rhantaticus, Sandracottus Sharp, 1882, Thermonectus Dejean, 1833) was conducted using the program TNT. Rhantaticus shares with all these genera several larval character states which support its inclusion in the Aciliini. Whereas Rhantaticus larva stands out from other known genera by several unique character states, our parsimony analysis did not recover any clear phylogenetic position of this genus within the Aciliini.

We describe for the first time the instar III larva of the diving beetle genus Hovahydrus Biström, 1982, based on H. praetextus (Guignot, 1951) and a new species yet to be described (identified here as Hovahydrus sp. near H. minutissimus (Régimbart, 1903)). We include detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi in order to discover useful characters for distinguishing Hovahydrus larvae from those of other known Hyphydrini (Coleoptera: Dytiscidae, Hydroporinae). A provisional parsimony analysis based on larval characteristics of 11 Hyphydrini species in eight genera was conducted using the program TNT. Larval morphology supports a close relationship between Hovahydrus, Hyphydrus Illiger, 1802, and the endemic South Africa genera Andex Sharp, 1882, Coelhydrus Sharp, 1882, Darwinhydrus Sharp, 1882 and Primospes Sharp, 1882. 

Sixty-seven species of the subfamily Pyraustinae from 17 genera and two tribes are listed. Anania verbascalis verbascalis ([Denis & Schiffermüller], 1949) is considered as a senior synonym of A. verbascalis parvalis (Osthelder, 1935) syn. n.; Pyrausta virginalis Duponchel, 1832 as a senior synonym of P. perkeo Amsel, 1970 syn. n.; and P. ferrealis (Hampson, 1900) as a senior synonym of P. euergestalis Amsel, 1954 syn. n. Thirteen species, namely Anania coronata (Hufnagel, 1767), A. murcialis (Ragonot, 1895), A. terrealis (Treitschke, 1829), Pyrausta ferrealis (Hampson, 1900), P. armeniaca Slamka, 2013, P. zeitunalis Caradja, 1916, P. cingulata (Linnaeus, 1758), P. delicatalis Caradja, 1916, P. tatarica Kemal et al., 2020, Loxostege sedakowialis (Eversmann, 1852), L. wagneri Zerny in Wagner, 1929, L. mucosalis (Herrich-Schäffer, 1848) and L. peltaloides (Rebel in Wagner, 1932), are newly reported from Iran. Additionally, a redescription of the male of P. delicatalis and the female of L. sedakowialis, as well as description of the hitherto unknown female of P. delicatalis are presented. The intraspecific variations of the species if present are discussed and additional new diagnostic characters to separate the closely related species are presented. Data on the geographical distribution of the Iranian species of this subfamily are provided.

Dario tigris, new species, is described from mountain streams south of Mogaung, in the Ayeyarwaddy River basin, Myanmar. It differs from congeneric species by its unique colour pattern, which consists of a series of eight straight vertical bars, the first two of which in males are ash-grey and the subsequent six are orange-red in life, combined with a series of small black spots arranged in three to four rows dorsolaterally on the head and nape. It differs further from its close relative Dario hysginon, with which it may occur syntopically, by fewer dorsal-fin spines (modally 14 vs modally 15), and fewer vertebrae (modally 12+12=24 vs modally 12+13= 25). Dario melanogrammus, new species, is another barred Dario from the Chindwin River basin. It differs from all other species of the genus by its zigzagging dark vertical bars; amongst Myanmar species, it can be further distinguished from D. hysginon and D. tigris by more vertebrae (modally 26 vs 25 in D. hysginon, and 24 in D. tigris).

Apistogramma ortegai, new species, is described from small streams tributaries of the Ampiyacu River near Pebas, in easternPeru. It belongs to the Apistogramma regani species group and is distinguished from all other species of Apistogrammaby the combination of contiguous caudal spot to bar 7, presence of abdominal stripes, short dorsal-fin lappets in both sexes,absence of vertical stripes on the caudal fin, and reduced number of predorsal and prepelvic scales.

A close analysis of a publication effort by the authors of the present paper suggests that they need to issue a clarificationto avoid confusion about the nomenclatural status of two species in the genus Australoheros, also known as chanchitos(‘piglets’).

Muscicapa dauurica Pallas, 1811 is shown to be an available name and the oldest available name for the Asian Brown Flycatcher

A new species of Setostephanolaimus, S. tchesunovi sp. n., is described from bottom sediments collected in the Skagerrak and Gullmarn Fjord off the west coast of Sweden. It is characterised by 1.0–1.3 mm long body, outer labial setae 6.5–8.5 μm long, cephalic setae 9–11 μm long, subcephalic setae 4–6 μm long, transversely-oval amphid, female with monodelphic opisthodelphic reproductive system, male with 6–9 tubular and without alveolar supplements, spicules arcuate and 54–64 μm long, gubernaculum with dorsal apophysis. A tabular compendium and dichotomous identification key to species of the genus Setostephanolaimus are provided.

Four known and one new species of Onchium are described from bottom sediments collected in Skagerrak off the west coast of Sweden. The following known species are redescribed: Onchium ocellatum Cobb, 1920, O. metocellatum Wieser, 1956, O. parocellatum (Allgén, 1940) and O. robustum Gerlach, 1965. Onchium longispiculum sp. n. is characterised by the 1.34–1.77 mm long body, anterior body end without cephalic capsule, anteriormost somatic sensilla located posterior to onchiostyle base, ocelli absent, excretory pore located at basis of lips, onchiostyle uniformly cylindrical, alveolar sup- plements indistinct, tubular supplements absent, spicules arcuate and 44–65 μm long. The new species has a unique set of characters (absence of developed ocelli and very long somewhat asymmetrical spicules) separating it from all other known species of the genus Onchium. The following nomenclatorial changes are proposed: O. conicaudatum (Allgén, 1935) is considered a junior synonym of O. metocellatum; O. conicaudatum apud Wieser, 1951 is considered a synonym of O. minutum Kito, 1981. The diagnosis of the genus Onchium is emended and a tabular compendium and dichotomous iden- tification key to species of the genus Onchium are provided.

Three known and two new species of Leptolaimoides are described from bottom sediments collected in Skagerrak off the west coast of Sweden. The following known species are redescribed: Leptolaimoides haploopis Jensen, 1978, L. tubulosus Vitiello, 1971 and L. hexatubulosus Hoang Lai-Phu et al., 2009. Leptolaimoides filicaudatus sp. n. is characterised by the 431–543 μm long body; cephalic sensilla papilliform; amphid 23–26 μm long, located 9–10 μm from anterior end; first body pore located 35–37 μm from anterior end; lateral field simple along most of body, areolated on tail, arising 36–40 μm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubu- lar and without alveolar supplements; spicules arcuate and 16 μm long. Leptolaimoides leptomicron sp. n. is characterised by the 776–847 μm long body; cephalic sensilla papilliform; amphid 15–17 μm long, located 9–13 μm from anterior end; first body pore located 40–46 μm from anterior end; lateral field areolated, arising 26–28 μm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with three tubular and without alveolar sup- plements, spicules arcuate and 28–29 μm long. The diagnosis of the genus Leptolaimoides is emended and a tabular com- pendium and dichotomous identification key to species of the genus Leptolaimoides are provided.

Leptolaimus timmi Vitiello, 1971 is redescribed from bottom sediments collected in the Skagerrak off the west coast of Sweden. New morphological data necessitate the transfer of this species to the genus Rhadinema Cobb, 1920. The main diagnostic characters of Rhadinema timmi (Vitiello, 1971) comb. n. include: 1.3–1.8 mm long body; rounded labial region weakly offset from body contour; cephalic setae 2–4 μm long; amphid located 12–19 μm from anterior end; first body pore located 22–30 μm from anterior end; lateral field absent; stoma tubular: cheilostom with six weakly cuticularised longitudinal rugae, gymnostom with sclerotized bar-shaped rhabdia, stegostom long, tubular; female without supple- ments, vagina without pars refringens, vulva midventral; male with 10–11 tubular and without alveolar supplements; spic- ules arcuate and 21–30 μm long.

A new genus Neocamacolaimus gen. n., with one new species N. parasiticus gen. n., sp. n. is described from the benthic polychaete Sphaerosyllis cf. hystrix collected in the Skagerrak off the west coast of Sweden. Neocamacolaimus gen. n. is placed in the family Camacolaimidae and is particularly characterised by having annulated cuticle with lateral alae; seti- form cephalic sensilla located at level with amphids; amphidial fovea ventrally spiral; buccal cavity without armament; pharynx muscular; nerve ring located at base of pharynx; male reproductive system diorchic with outstretched testes; spic- ules weakly arcuate with straight manubrium; gubernaculum absent; alveolar supplements located in the pharyngeal re- gion; tubular supplements absent; tail conoid; caudal glands and spinneret present. Juveniles of this genus are particularly characterised by their parasitic lifestyle and the following unique morphological features: lips form a dorso-ventrally elon- gated perioral disc with internal sclerotizations: one midventral and two dorsosublateral (right and left); cephalic sensilla setiform, subventral sensilla are noticeably longer than the subdorsal ones; intestine extends posterior to rectum and anal opening, forming a post-anal pouch.

Following many decades of work on the taxonomy, biology and ecology of the globally-distributed tropical earthworm Pontoscolex corethrurus (Muller, 1857), morphological and molecular data have shown that the stability and effectiveness of nomenclature depends on the designation of a neotype from the type locality. We do that, with all the required justifications, and provide sufficient information to permit the correct identification of this species.

Eighteen new species of Oecetis are described, diagnosed, and illustrated from New Caledonia: Oecetis amphora sp. nov., Oecetis ovula sp. nov., Oecetis ramosa sp. nov., Oecetis loyolaensi sp. nov., Oecetis millei sp. nov., Oecetis christinae sp. nov., Oecetis rostrata sp. nov., Oecetis alicae sp. nov., Oecetis oxybelis sp. nov., Oecetis dorsospina sp. nov., Oecetis multidentata sp. nov., Oecetis gracilis sp. nov., Oecetis rostra sp. nov., Oecetis triramosa sp. nov., Oecetis flucta sp. nov., Oecetis nouvellecaledoniensis sp. nov., Oecetis variabilis sp. nov., and Oecetis ovata sp. nov. A diagnostic key is provided for males of Oecetis species of New Caledonia. The species display similarities in genitalic characteristics but also a high diversity of apomorphic features. The new species were collected from lotic habitats across most of Grande Terre.

The following six new Oecetis species have been described and illustrated: O. lata, O. gretae, O. malickyi, O. porntipae, O. olahi, and O. hageni. The following three Oecetis species are recorded for the first time from Vietnam: O. maron Malicky & Chantaramongkol 2005 (in Malicky 2005), O. iakchos Malicky 2005, and O. jachin Malicky & Mey 2010 (in Malicky 2010a). We present new records of the following six Oecetis species that are previously known from Vietnam: O. raghava Schmid 1995, O. biramosa Martynov 1936, O. tripunctata (Fabricius 1793), O. meleagros Malicky & Thani 2005, O. asmada Malicky 1979, and O. empusa Malicky & Chaibu 2000. A map presents the distribution of the Oecetis species included in this report.

Devario comprises 38 potentially valid species in southern Asia. Ten species of Devario have been reported so far from Myanmar, six of which belong in the group of striped devarios, with predominantly horizontal stripes in the colour pattern.Among them, records of D. aequipinnatus most likely represent misidentifications. Remaining species of striped devariosin Myanmar are known only from brief descriptions and are in need of taxonomic revision. Devario yuensis and D. deruptotalea,known previously only from India, are here reported for the first time from Myanmar. Devario fangae, new species,is described on the basis of specimens collected in 1998 from small streams in Putao in the extreme north ofMyanmar. These streams drain to the Mali Hka River, a tributary of the Ayeyarwaddy River. Devario fangae sharesuniquely with D. browni and D. kakhienensis an anterior expansion in width of the middle dark stripe on the side (P stripe).It differs from D. browni and D. kakhienensis in presence of a broad P stripe, wider than adjacent interstripes, vs. narrow,as wide as or narrower than interstripes. Devario fangae is further similar to other species of Devario characterized bythree dark stripes (P, P+1, P-1) along the side, but differs from these in having all three stripes wide and of about equalwidth vs. P stripe wide and P+1 and P-1 stripes much narrower. The largest specimen of D. fangae is 61.0 mm SL. Females are significantly more deep-bodied than males. A specimen of D. aequipinnatus reported from Putao in 1919 probablyr epresents D. fangae.Devario myitkyinae, new species, is described on the basis of specimens collected in 1997 and 1998 from a streamand lake in the Ayeyarwaddy River drainage near Myitkyina in northern Myanmar. It is similar to D. browni and D.kakhienensis, but different from D. fangae in having horizontal stripes on side equal in width, narrow, irregular, and to some extent curved away from horizontal extension. Devario myitkyinae differs from D. browni, D. kakhienensis, and D.fangae in absence of anterior widening of the P stripe. Devario myitkyinae is similar to other species of Devario characterized by three dark stripes (P, P+1, P-1) along the side, but differs from these in having all three stripes irregularand of equal width vs. stripes regular, P stripe wide and P+1 and P-1 stripes much narrower. The largest wild specimen of D. myitkyinae is 68.7 mm SL. A specimen collected near Myitkyina and reported as D. aequipinnatus in 1929 probably represents D. myitkyinae.

Gustaf Johan Billberg’s review of ichthyology, published in Swedish in 1833 in the Linnéska samfundets handlingar, mentions92 fish taxa at genus and species level, 41 of which represent new taxa, unnecessary replacement names, or unjustifiedemendations. Billberg presents his own classification of fishes, in which five new family names are introduced:Ballistidae, Diodontidae, Ooididae, Chironectidae, and Macrorhyncidae. Diodontidae has priority over Diodontidae Bonaparte, 1835. Macrorhyncidae was published earlier than Gempylidae Gill, 1862, but the latter has priority by prevailingusage.Billberg mentions 61 genera of fishes, 41 of them listed only by name. Six generic names proposed by Billberg are available as unjustified emendations: Myxinus, Petromyzus, Scylia, Mustellus, Zyganna, and Ballistes. Brachionus is anunnecessary replacement name. Aphrus, Capriscus, Exormizus, Enneophthalmus, and Oedaus are nomina nuda. Eight new genera of fishes are proposed: Anodon, Posthias, Orbis, Sphaeroides, and Ooides are junior synonyms; Cotilla is anomen oblitum in relation to Sufflamen Jordan, 1916; Tropigaster a nomen oblitum in relation to Aracana Gray, 1835;and Tetragonizus a nomen oblitum in relation to Lactoria Jordan & Fowler, 1902.Billberg lists 31 species of fishes. Three represent new combinations; two are nomina nuda. The following 14 newspecies are described based on literature: Raja forskohlii, Cephaloptera dumerillii, Myliobatis lacepedei, Scylia russelii,Anodon macropterus, Cotilla frenata, Monacanthus blochii, M. sebae, M. cuvieri, M. marcgravii, Tetraodon striatus,Orbis psittacinus, Orbis punctulatus, and Orbis guttatus. All of those are invalid, except Scylia russelii, which is a species inquirenda. The following nine species group names are unnecessary replacement names and consequentlyinvalid: Raja arabica, Myliobatis rissoi, Scylia isabellina, Anodon cirrhosus, Anodon cornutus, Zyganna voracissima,Centrina broussonetii, Acipenser vulgaris, and Acipenser ichthyocolla.Three species of pipefishes of the family Syngnathidae are described and figured by Billberg from drawings ofspecimens observed on the Swedish West Coast. Syngnathus virens and S. pustulatus are junior synonyms of S. typhle Linnaeus, 1758. Syngnathus palmstruchii is a junior synonym of Entelurus aequoreus (Linnaeus, 1758).

Fish species names based on the family name of Eduard Rüppell are reviewed, and it is concluded that Nemachilichthys ruppelli correct name for Cobitis rupellii Sykes, 1839

Danio feegradei Hora is redescribed based on recently collected specimens from small coastal streams on the western slope of the Rakhine Yoma, ranging from the Thade River drainage southward to slightly north of Kyeintali. Danio absconditus,new species, is described from the Kyeintali Chaung and small coastal streams near Gwa, south of the range of D. feegradei. Both species are distinguished from other Danio by the presence of a dark, elongate or round spot at the baseof the caudal fin and a cleithral marking composed of a small black spot margined by a much smaller orange spot. Danio feegradei is characterized by the colour pattern, with series of white spots along the otherwise dark side; D. absconditusby about 7–11 dark vertical bars on the abdominal side. Within Danio, the presence of a complete lateral line, cleithralspot, and 14 circumpeduncular scales is shared with D. dangila and similar species, but these character states may be plesiomorphicas suggested by the shared presence of cleithral spot and complete lateral line in Devario and Betadevario. In other Danio the cleithral spot is absent, the lateral line is short or absent, and the circumpeduncular scale count is lower(10–12). Twenty teleost species are reported from streams on the western slope of the Rakhine Yoma, all probably endemic.The parapatric distribution of D. absconditus and D. feegradei is unique within the genus, and may be partly explainedby changes in eustatic sea levels.

Chalinochromis cyanophleps is described from nine specimens, the largest 129 mm SL, from Namansi. It differs fromother species of Chalinochromis in plain trunk colouration, absence of black stripes on the head, relatively narrow lips, presence of tricuspid jaw teeth, and presence of five rather than four dentary lateralis foramina. The blue iridescent stripe below the eye is shared with other lamprologin cichlids, but is broader and more conspicuous in C. cyanophleps.

Chalinochromis cyanophleps occurs at depths between 6 and 45 m in rocky habitats along the Tanzanian coast of Lake Tanganyika,from Mvuna Island south to Kalala Island, a stretch of about 90 km. Field observations were made of specimens up to 18 cm total length. The COI DNA barcode sequence differs by 1.8% from that of C. popelini.

Danio htamanthinus, new species, is described from small streams in the vicinity of Htamanthi on the middle Chindwin River. It is most similar to D. choprae and D. flagrans from the Ayeyarwaddy River drainage, sharing the same elaborate colour pattern with dark vertical bars and a red interstripe along the posterior side, but is distinguished by the absence of a P+1 stripe and presence of a P stripe represented only by small spots. The uncorrected p-distance in the mitochondrial COI gene separates D. htamanthinus from D. choprae by 4.3% and from D. flagrans by 7.5%. The largest specimen is only 22.9 mm in standard length (male holotype), but the holotype and one other male, 19.5 mm SL, feature sex-specific pectoral-fin tubercles, and a female as small as 16.6 mm SL has ripening ova.In a phylogenetic analysis based on COI sequences, D. htamanthinus is sister taxon of D. flagrans+D. choprae, and those three species are sister group of D. margaritatus+D.erythromicron.

Specimens of Devario from a tributary to the Salween River in Myanmar initially identified as Devario browni but witha different colour pattern, were subjected to a comparative morphological analysis with syntypes and other specimens of D. browni from near its putative type locality. The Salween sample was recognised as representing a distinct species, here named Devario ahlanderi. No significant morphometric differences were found between D. ahlanderi and D. browni.The type series of Devario ahlanderi differed from D. browni and most other species of Devario in the presence of 14 vs 12 circumpeduncular scale rows. Devario ahlanderi, D. browni, and D. fangae shared subadult colour pattern. Adult D. ahlanderi differed from adult D. browni in the trunk colour pattern, consisting of rows of dark blotches or short vertical bars. In D. browni, the flank colour pattern consisted of horizontal dark stripes, the middle of which (the P stripe) frequently diverged anteriorly, enclosing a small light blotch. Specimens previously reported as D. browni from the upper Salween River basin in Yunnan differed slightly in colour pattern, and may represent a distinct species. Devario ahlanderi shared spotted colour pattern with that of one ontogenetic state in D. kysonensis, except that a row of spots marking the P-1 stripe in D. kysonensis was absent in D. ahlanderi. The minimum genetic distance between D. ahlanderi and congeneric species varied from 2.1 to 5% in the mt-coI gene.

Osteobrama cotio is considered to be a widespread species in India and Bangladesh. Mitochondrial DNA (COI, 16S rRNA)shows that populations from the Meghna River, Karnafuli and Sangu Rivers, Narmada River, and Godavari River aregenetically distinct from each other. No morphological differences were found to separate Meghna and Karnafuli+Sangu populations, however. A putative new species, “Osteobrama serrata” has been described from the Barak River basin, statedto be distinguished from O. cotio by the presence of a serrated third dorsal-fin ray. The description of “O. serrata” doesnot fulfil requirements of the International Code of Zoological Nomenclature, (International Commission on ZoologicalNomenclature 1999) and the name is thus unavailable. Published DNA sequences of “Osteobrama serrata” are identicalto sequences of O. cotio from Bangladesh. As mentioned already in the original description, O. cotio has a serrated third dorsal-fin ray.

Danio annulosus, new species, is described from a small pool below the Shuvolong Falls in the Kaptai Lake system in Bangladesh. It shares with chain danios (D. assamila, D. dangila, D. catenatus, D. concatenatus, and D. sysphigmatus) a colour pattern consisting of series of dark rings with light interspaces along the side, complete lateral line, 14 cir-cumpeduncular scales, a produced first ray in the pectoral fin, and a black humeral spot. It differs from other chain danios in possessing much shorter pectoral and pelvic fins, and a humeral spot that is slightly wider than deep instead of round or deeper than wide. The mitochondrial cytochrome c oxidase subunit I (COI) sequence separates D. annulosus from the most similar species, D. catenatus by a p-distance of 3.4%. Although recorded from only a single locality, Danio annulosus is expected to have a wider distribution in the Karnafuli River drainage

The native distribution of the small labyrinth fish species Pseudosphromenus cupanus includes southern India and Sri Lanka. According to literature it has a range including also Pakistan, Bangladesh, Myanmar, Malaysia, and Indonesia (Sumatra) but there are no voucher specimens or reliable observations from those areas. The distribution record of P. cupanus was inflated partly by including P. dayi as a synonym. Pseudosphronemus dayi is native to the Western Ghats in India, but the origin of the aquarium importation in 1907 was reported as both Cochin (=Kochi) and Malacca (=Malaysia), the latter locality obviously in error. The basis for the Sumatra record is an obviously mislabeled sample of P. dayi from Pulau Weh close to Sumatra. The basis for reporting the species from Pakistan, Myanmar or Bangladesh could not be located. Misidentified museum specimens from Myanmar and Pakistan identified as P. cupanus were never published on. Pseudosphromenus cupanus has been considered recently to be extinct in Bangladesh, but in fact it never occurred there.