The purpose of this application, under Article 75.6 of the Code, is to set aside all previous fixations of name-bearing types for the species Tipula marciLinnaeus, 1758 and Tipula febrilisLinnaeus, 1758 (currently Bibio marci and Dilophus febrilis, the St. Mark's fly and the fever fly, respectively) and to designate neotypes in their place. Illustrations in pre-Linnaean works cited by Linnaeus in connection with these names are unidentifiable, and extant Linnaean syntypes of these two nominal species belong to other species than those for which the names have been consistently used since the early 19^th century.

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the specific name Nebela militarisPenard, 1890, a junior subjective synonym of Nebela bursellaTaranek, 1881 – referred to as Nebela bursella Vejdovský in the literature. Due to the absence of any type or reference specimen and due to the confusing original description, doubts about the taxonomic status of N. bursella persist. A review of the literature revealed that the names N. militaris and N. bursella originally referred to the same species, with the name N. bursella later being applied erroneously to another species. According to the Principle of Priority, N. bursella is the valid name of the species generally known as N. militaris, but there has been no mention of the former taxon since 1964 and its name is unknown to most active testate amoeba researchers. To avoid confusion, we propose to conserve the widely used species name Nebela militarisPenard, 1890 by granting it conditional precedence over Nebela bursellaTaranek, 1881, and to designate a neotype.

The purpose of this application, under Article 23.9.3 of the Code, is to conserve at both the family and superfamily level the widely used family-group name Tyrannosauridae (-oidea) Osborn, 1906 (Dinosauria, Theropoda), which is threatened by its senior subjective synonyms Deinodontidae (-oidea) Cope, 1866 and Dryptosauridae (-oidea) Marsh, 1890. Strict application of the Code would result in unnecessary confusion in dinosaur taxonomy since the names Tyrannosauridae and Tyrannosauroidea have been used consistently in the vertebrate paleontological literature since the 1970s with only a very few exceptions.

The International Commission of Zoological Nomenclature has declined to emend to cheesemanae the spelling of the specific name of a hylid tree frog from Papua New Guinea, Nyctimystes cheesmani Tyler, 1964.

Under the plenary power, the International Commission on Zoological Nomenclature has emended the spelling of the family-group name StenoderinaePascoe, 1867 (Insecta, Coleoptera, Cerambycidae) to remove homonymy with StenoderiniSelander, 1991 (Insecta, Coleoptera, Meloidae). The stem of the generic name StenoderusDejean, 1821 has been emended to Stenoderus- to give the family-group name Stenoderusinae while the family-group name based on StenoderaEschscholtz, 1818 remains unchanged.

The International Commission on Zoological Nomenclature has declined to use its plenary power to designate a neotype for Anolis chlorocyanus Duméril & Bibron, 1837. As a result, the specific name Anolis chlorocyanus Duméril & Bibron, 1837, will have priority over A. coelestinus Cope, 1862 as the valid name for the well-known, predominantly North Island Hispaniolan anole species. The species known as Anolis chlorocyanus since Dunn (1930) needs to be renamed.

The International Commission on Zoological Nomenclature has declined to use its plenary power to conserve the specific name of Geophilus alpinus Meinert, 1870 for a European species of geophilomorph centipede. As a result, the name impressus C.L. Koch, 1847 as published in the binomen Geophilus impressus has priority over the names palustris C.L. Koch, 1863, as published in the binomen Geophilus palustris and alpinus Meinert, 1870, as published in the binomen Geophilus alpinus whenever the former is considered synonymous with either of the latter.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the accustomed usage of the specific names of Varanus indicus (Daudin, 1802) and Varanus chlorostigmaGray, 1831 by replacing the neotype specimen of Tupinambis indicusDaudin, 1802 with a new neotype that belongs to the original taxonomic species involved.

The International Commission on Zoological Nomenclature has declined to use its plenary power to conserve the specific name of Geophilus bonensis Meinert, 1870 (currently Gnathoribautia bonensis) for a species of geophilomorph centipede. As a result, the name punctiventris Newport, 1844, as published in the binomen Necrophloeophagus punctiventris, has priority over the name bonensis Meinert, 1870, as published in the binomen Geophilus bonensis, whenever they are considered synonyms.

The International Commission on Zoological Nomenclature has declined to use its plenary power to conserve the specific name of Phrynus mexicanus Poinar & Brown, 2004 for a fossil whip spider, a junior primary homonym of Phrynus mexicanus Bilimek, 1867 (currently Paraphrynus mexicanus). As a result, the name Phrynus mexicanus Poinar & Brown, 2004 is invalid and needs to be replaced.

Under the plenary power, the International Commission on Zoological Nomenclature has emended the spelling of the family-group name CharinidaeGray, 1849 (Reptilia, Squamata, Serpentes) to remove homonymy with CharinidaeQuintero, 1986 (Arachnida, Amblypygi). The stem of the generic name CharinaGray, 1849 has been emended to Charina- to give the family-group name Charinaidae for the former while the latter family-group name based on Charinus Simon in Raffray, Bolivar & Simon, 1892 remains unchanged. The Commission has also used its plenary power to emend the spelling of the family-group name UngaliopheinaeMcDowell, 1987 to UngaliophiinaeMcDowell, 1987.

The International Commission on Zoological Nomenclature has conserved the species-group names leucorynchusLinnaeus, 1771 and mascarinusLinnaeus, 1771 as respective justified emendations of the specific names for a woodswallow, Artamus leucorynchus (Linnaeus, 1771), type species of the avian genus Artamus (Artamidae), and a parrot, Mascarinus mascarinus (Linnaeus, 1771), type species of the avian genus Mascarinus (Psittacidae). Both names were originally spelled by Linnaeus (1771) in his Mantissa Plantarum Altera as “leucoryn.” and “mascarin.”, in the binomina Lanius leucoryn. and Psittacus mascarin. respectively.

As demonstrated by Wright (2015), the Curl-crested Aracari was originally named Pteroglossus beauharnaisii by Wagler in 1831; in the following year, the same author used the subsequent combination P. beauharnaesii (Wagler, 1832). Based on the evidence, Wright concluded that the valid name of the taxon was Pteroglossus beauharnaisii. Bock & Schodde (2016) disagreed, arguing that beauharnaisii was not used after 1899 and was thus a nomen oblitum, while beauharnaesii had been universally applied and should be used. Here, those objections are refuted, based on the facts and correct application of the articles in the International Code of Zoological Nomenclature (hereafter the Code; ICZN, 1999) invoked by Bock & Schodde (2016).

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the specific name of a well-known dung beetle, Onthophagus anthracinusHarold, 1873, a junior primary homonym of Onthophagus anthracinusFaldermann, 1835. Onthophagus anthracinusFaldermann, 1835 was synonymized with Onthophagus histeroidesMénétriés, 1832, which in turn was included in the genus CaccobiusThomson, 1859. After its synonymization in 1846, the senior homonym was never again used as valid, thus meeting the criteria of Article 23.9.1.1, but the junior homonym has not been cited in enough works during the past 50 years to meet the criteria of Article 23.9.1.2 for automatic reversal of precedence of the two homonyms. For the sake of stability it is proposed that the Commission use its plenary power to allow use of Onthophagus anthracinusHarold, 1873 as valid despite its status as a junior primary homonym of Onthophagus anthracinusFaldermann, 1835.

The purpose of this application, under Article 55.3.1 of the Code, is to remove the homonymy of EuchromiiniLéger, Landry & Nuss, 2019 (Lepidoptera, Crambidae) (type genus EuchromiusGuenée, 1845) with EuchromiinaeButler, 1876 (Lepidoptera, Erebidae) (type genus EuchromiaHübner, 1816) by emending the former to Euchromiusini.

Under the plenary power, the International Commission on Zoological Nomenclature has conserved the family-group name OrtalidiniDonegan, 2012 (Aves, Cracidae) with this spelling and authorship by suppressing all family-group names based on OrtalisFallén, 1810 (Insecta, Diptera). As a result, OrtalidainiDonegan, 2012 is an incorrect original spelling, and OrtalisiniDavid, 2014 is an unjustified emendation of OrtalidiniDonegan, 2012.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the specific name of Scarabaeus gazellaFabricius, 1787 by designating a neotype.

The International Commission on Zoological Nomenclature has conserved the usage of the family-group name SphenopidaeHertwig, 1882 for a group of brachyneminic zoantharians over its rarely-used senior subjective synonym Palythoidae Duchassaing de Fombressin & Michelotti, 1860.

The International Commission on Zoological Nomenclature has used its plenary power to designate a neotype to replace the non-diagnostic lectotype for the species Allodaposuchus precedensNopcsa, 1928.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the current usage of the generic name HeteronychusDejean, 1833 by setting aside all previous type fixations for this genus preceding that of Geotrupes cricetusHausmann, 1807 by Krell in 2002.

The widely used polychaete names DorvilleaParfitt, 1866, and consequently DorvilleidaeChamberlin, 1919 (Annelida, Errantia) are threatened by a senior homonym DorvilleaLeach, 1852 (Mollusca, Bivalvia). The latter is a junior synonym of AbraLamarck, 1818 and it has not been used as a valid name since 1899, while the former has been used as a valid name in over 25 publications by more than 10 authors in the last 50 years. Therefore, under Article 23.9.2 of the Code, DorvilleaParfitt, 1866 must be regarded as a nomen protectum and DorvilleaLeach, 1852 must be regarded as nomen oblitum. This act will also protect DorvilleidaeChamberlin, 1919, which is in prevailing usage for this family of marine annelids.

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the specific name of the shovelhead worm, Magelona minutaEliason, 1962 (Annelida, Magelonidae), in the interest of nomenclatural stability. Magelona minuta is distributed from Scandinavia to West Africa and its name has appeared extensively in ecological and taxonomic works, polychaete guides and biodiversity reports. However, in 1959 Wilson had already described a variety of Magelona filiformisWilson, 1959 as M. filiformis minuta. Having been proposed prior to 1961, this trinomen is both the available name of a subspecies under Article 45.6.4 of the Code and a senior primary homonym of M. minutaEliason, 1962. Particularly for ecologists, the introduction of a new name for Eliason's well-known species would represent an undesirable disturbance to established nomenclature; therefore, suppression of M. filiformis minutaWilson, 1959 is proposed.

The purpose of this application, under Article 55.3.1 of the Code, is to resolve the homonymy between the family-group names Hemiarthrinae Markham, 1972, with type genus Hemiarthrus Giard & Bonnier, 1887 (Arthropoda, Malacostraca), and Hemiarthridae Sirenko, 1997, with type genus Hemiarthrum Carpenter in Dall, 1876 (Mollusca, Polyplacophora). It is proposed that the Commission declare the stem of the generic name Hemiarthrum Carpenter in Dall, 1876 to be Hemiarthrum-, resulting in a change of the spelling of the name Hemiarthridae Sirenko, 1997 to Hemiarthrumidae.

The purpose of this application, under Article 23.9.5 of the Code, is to conserve the specific name of Helix spirorbis Deshayes, 1859 (currently Scolodonta spirorbis), a junior primary homonym of Helix spirorbisLinnaeus, 1758 (currently Anisus spirorbis). These names are currently in use, respectively, for species in two different families of terrestrial (Scolodontidae) and freshwater (Planorbidae) gastropods, that belong to different superorders. Both names have been treated as valid since they were proposed and both were transferred out of the genus HelixLinnaeus, 1758 before 1899. In fact, H. spirorbis Linnaeus had been reassigned even before Deshayes described his species. It is proposed that Helix spirorbis Deshayes, 1859 be conserved by ruling it is not invalid by reason of being a junior homonym of Helix spirorbisLinnaeus, 1758.

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the name Marmosa isthmicaGoldman, 1912 for a species of small Neotropical marsupial. This specific name, which has been used consistently for over a century, is threatened by a senior synonym, Marmosa reginaThomas, 1898, which has been applied incorrectly until very recently.

The International Commission on Zoological Nomenclature has conserved the names Iberolacerta and Darevskia for two genera of lacertid lizards by confirming their availability from Arribas (1999). The microfiche publication (Arribas, 1997) is confirmed as unavailable and placed on the Official Index of Rejected and Invalid Works in Zoological Nomenclature. The name CaucasilacertaHarris, Arnold & Thomas, 1998 is confirmed as a nomen nudum and placed on the Official Index of Rejected and Invalid Generic Names in Zoology.

The International Commission on Zoological Nomenclature has conserved the specific name of Garypus latus Hansen, 1884 for a species of pseudoscorpion from northern and central Europe by giving it precedence over its senior subjective synonym Garypus hungaricus Tömösváry, 1882 whenever the two are considered synonyms.

The International Commission on Zoological Nomenclature has conserved the usage of the generic name RipiphorusBosc, 1791, type genus of RipiphoridaeLaporte, 1840, by designating Ripiphorus subdipterusFabricius, 1792 as its type species.

The International Commission on Zoological Nomenclature has conserved the usage of the family-group name ErynniniBrues & Melander, 1932 for a tribe of hesperiid butterflies by suppressing its senior homonyms ErynnidiTutt, 1906, ErynnidaeSwinhoe, 1913 and ErynnidaeHampson, 1918.

The International Commission on Zoological Nomenclature has conserved the specific name of Dasypeltis atraSternfeld, 1912 for a species of colubrid snake from central and eastern Africa by giving it precedence over its senior subjective synonym Dasypeltis lineolataPeters, 1878, whenever the two are considered synonyms.

The International Commission on Zoological Nomenclature has conserved the usage of the family-group name PlatypleuriniSchmidt, 1918 for a group of Old World cicadas over its senior subjective synonym HamzariaDistant, 1905.

The International Commission on Zoological Nomenclature has conserved the usage of the generic name StenonasterLambert, 1922, the type genus of the family StenonasteridaeLambert & Thiéry, 1924, an important missing link between two major atelostomate echinoid groups, by suppressing their rarely used, senior subjective synonyms Stenocorys Lambert & Thiéry inLambert, 1917 and StenocoridaeLambert, 1920.

Until now, authorship of the sauropodomorph dinosaur genus Coloradisaurus has been attributed to Lambert, 1983. Here we demonstrate that Lambert's work does not meet the requirements of Articles 13.1 and 13.3 of the Code for availability of this name, therefore it is a nomen nudum in that publication. Instead, it was inadvertently made available a few years later by another worker, as ColoradisaurusGalton, 1990.