The purpose of this application, under Articles 55.3.1 and 78.2.3 of the Code, is to resolve the homonymy between the family-group names RivuliniGrote, 1895 in Lepidoptera and RivuliniMyers, 1925 in Pisces. It is proposed that the stem of the generic name Rivula Guenée in Duponchel, 1845 be emended to Rivula-, so as to change the spelling of the moth family-group name, currently as the subfamily Rivulainae, while leaving the fish family-group name unaltered.

The purpose of this application under Article 75.6 of the Code is to conserve the specific names of the European ‘Small Apollo’ butterfly Parnassius phoebus (Fabricius, 1793) and the Altai ‘Apollo’ butterfly Parnassius ariadne (Lederer, 1853) in their current usage. Hanus & Theye (2010) discovered that the traditional concept of the name P. phoebus was a misidentification and published actions contrary to Art. 75.6. We herein request that the International Commission on Zoological Nomenclature use its plenary power to set aside all previous type fixations for the nominal species Papilio phoebusFabricius, 1793, and to designate a neotype representative of the current usage of P. phoebus.

The purpose of this application, under Articles 78.1 and 81.1 of the Code, is to suspend the application of Art. 35.5 so as to re-establish the precedence of MegaperidaeManter, 1934 over ApocreadiinaeSkrjabin, 1942 for certain digenean trematodes of fish. Both names have been used as valid in recent literature, with some authors treating the former as a subfamily (MegaperinaeManter, 1934) of the latter, which is now treated also as a family (Apocreadiidae Skrjabin, 1942). While Apocreadiidae may possibly be regarded as enjoying prevailing usage, Megaperidae is the older name, and its supposed lack of precedence under Art. 35.5 is an aberrancy resulting from historical contingencies.

The purpose of this application, under Article 81.2 of the Code is to protect the names LucernaSwainson, 1840 and LucerninaeSwainson, 1840 as treated by Sei et al. (2017) by the suppression of Lucerna Férussac, 1821, a name originally published in synonymy and available under Art. 11.6.1, but subsequently not used in its original meaning.

The purpose of this application, under Articles 29 and 55.3.1 of the Code, is to remove the homonymy of CepheidaeBerlese, 1896 (type genus CepheusKoch, 1835) (Acariformes) with CepheidaeAgassiz, 1862 (type genus CepheaPéron & Lesueur, 1810) (Cnidaria), by emending the former to CepheusidaeBerlese, 1896. These two family-group names are based on similar but not identical type-genus names.

The purpose of this application, under Articles 23.9.3, 78.1 and 80.2 of the Code, is to suppress the senior synonym Helix diodonRossmässler, 1835, in order to protect the name Helix dibothrionBielz, 1860 (currently Perforatella dibothrion), which has been consistently in use for more than a century and to conserve the commonly used but incorrect spelling of the name.

The purpose of this application under Article 78.2.3 of the Code is to stabilize the spelling of various junior subjective synonyms of the fish family Rivulidae proposed before 2000. The confirmation of -lebi- as the correct genitive stem under the Code for fish genera with names ending in -lebias is requested.

The International Commission on Zoological Nomenclature has voted to adopt Candidate Part Phylum Rotifera, genus-group names established before 1 January 2000, and Candidate Part Phylum Rotifera, species-group names established before 1 January 2000, both compiled by Jersabek et al., 2018. Both Parts are hereby placed on the List of Available Names in Zoology.

The International Commission on Zoological Nomenclature has conserved the usage of the specific name of Podocnemis unifilisTroschel, 1848 for a widely distributed species of Amazonian turtle, by giving it precedence over its rarely used senior subjective synonym Emys cayennensisSchweigger, 1812 (currently Podocnemis cayennensis).

The International Commission on Zoological Nomenclature has conserved the usage of the specific names of Scarabaeus ferrugineus Olivier, 1789 (currently Metacatharsius ferrugineus) (Scarabaeidae) and Scarabaeus ferrugineusPalisot de Beauvois, 1809 (currently Bradycinetulus ferrugineus) (Geotrupidae) by ruling that the latter nominal species is not invalid by reason of being a junior homonym of the former.

The International Commission on Zoological Nomenclature has conserved the specific name of Metochus abbreviatus Scott, 1874 for a species of rhyparochromid bug by giving it precedence over the senior subjective synonym Rhyparochromus erosusWalker, 1872.

The fish genus CookeolusFowler, 1928 has been in use for a genus of long-finned bigeyes for 90 years, with the combination Cookeolus japonicus (Cuvier, 1829) being widely listed as the only species in the genus. However, the type species of the genus, Anthias boops Schneider in Bloch & Schneider, 1801, is a junior synonym of another bigeye species, Heteropriacanthus cruentatus (Lacepède, 1801) and does not conform morphologically with the bigeye species currently known as Cookeolus japonicus, as noted by Starnes (1988). Given that Cookeolus is currently in usage for the bigeye species Priacanthus japonicus, and using Article 70.3, the type species of Cookeolus is changed to Priacanthus japonicus to avoid nomenclatural instability and confusion in the technical literature.

Utahraptor is the largest member of the dinosaur family DromaeosauriDae and represents one of the most remarkable discoveries in recent decades. In the original description, the specific epithet ostrommaysi was used for naming the species in honor of two different persons, but in subsequent years the spelling ostrommaysorum was often used without comment or explanation. In this paper, we review the historical uses of the specific epithet of Utahraptor and make clarifications on the status of six different subsequent spellings. The International Code of Zoological Nomenclature (1999) does not offer any provision for forming a genitive form from two persons having different names, so the original spelling ostrommaysi has to be regarded as an arbitrary combination of letters, and not a correctly formed genitive form. For this reason, it is deemed to be preserved unaltered and is not subject to a justified emendation; consequently, the subsequent spelling ostrommaysorum is erroneous and represents an unjustified emendation and shown not to be in prevailing usage. Therefore, the name to be used for the taxon is Utahraptor ostrommaysi, as originally introduced.

The purpose of this application, under Article 23.9.3 of the Code, is to suppress the unused name Clausilia ventricosa var. quadriplicataFitzinger, 1833, in order to conserve the name Clausilia quadriplicataSchmidt, 1868 (currently Quadriplicata quadriplicata), which has been consistently in use since its inception, and for which no junior replacement name is available.

The purpose of this application, under Article 75.6 of the Code, is to conserve the current universal usage of the name Neoseiulus californicus (McGregor, 1954) (Phytoseiidae) for a mite species that is used worldwide as a commercial biological control agent. The type specimens of Typhlodromus californicusMcGregor, 1954 and of its putative synonym T. mungeriMcGregor, 1954, both formerly considered lost, were recently located and studied. After examination, it is clear that the current concept of N. californicus is not consistent with the type material and represents a distinct species. Furthermore, the T. californicus and T. mungeri types match the morphological characters of N. barkeriHughes, 1948, for which the lectotype and a paralectotype were examined. It is proposed that the previous type fixations for nominal species N. californicus be set aside, and that a neotype specimen consistent with the current universal usage of the name N. californicus be designated.

The purpose of this application, under Articles 70.2 and 81.1 of the Code, is to preserve stability in the nomenclature of the beetle family Tenebrionidae by designating Cnodalon virideLatreille, 1804 as the type species of CnodalonLatreille, 1797. The discovery that Cnodalon virideLatreille, 1804, currently considered the type species of the genus Cnodalon, is not an originally included nominal species in the genus Cnodalon, and so not available as the type species, results in disruptive nomenclatural changes in the family Tenebrionidae if another type species is selected.

The purpose of this application, under Article 75.5 of the Code, is to replace the unidentifiable female lectotype of the Neotropical shield bug Rhyncholepta grandicallosaBergroth, 1911 (Pentatomidae, Pentatominae, Chlorocorini), with a recently collected male neotype from the type locality, French Guiana.

The purpose of this application, under Article 23.9.5 of the Code, is to conserve the specific name Ateuchus costatusWiedemann, 1823, a junior primary homonym of Ateuchus costatusThunberg, 1818. These names are currently in use and have not been treated as congeneric since 1869, when the homonyms were transferred to the genera Scarabaeus Linnaeus, 1758 and Sisyphus Latreille, 1807, respectively. It is highly unlikely that these names will be considered congeneric in the future. Therefore, it is proposed that Ateuchus costatusWiedemann, 1823 be conserved by ruling that it is not invalid by reason of being a primary junior homonym of Ateuchus costatusThunberg, 1818.

The purposes of this application, under Articles 78.4.1 and 23.9.3 of the Code, are 1) to request a review and reversal of Opinion 2404 issued by the Commission in 2017 in response to Case 3633, and 2) to conserve the specific name Exaiptasia pallida (Agassiz in Verrill, 1864) for a species of sea anemone (Cnidaria, Actiniaria) that is widely used as a model system for studies of dinoflagellate-cnidarian symbiosis and coral bleaching. Exaiptasia diaphana (Rapp, 1829) is the senior subjective synonym of E. pallida. The requirements for reversal of precedence (Art. 23.9.1) of the name E. pallida with respect to E. diaphana are not all met, specifically Art. 23.9.1.1. In the interest of minimizing taxonomic confusion and maintaining nomenclatural stability, we propose to conserve the use of the junior synonym E. pallida in place of the senior synonym E. diaphana.

The International Commission on Zoological Nomenclature has declined to use its plenary power to set aside the existing lectotype of Chionobas chryxusDoubleday, 1849 and to designate a neotype. However, the International Commission on Zoological Nomenclature has used its specific powers to confirm that the name-bearing type is the male specimen illustrated in Doubleday (1849).

The International Commission on Zoological Nomenclature has designated Plateosaurus trossingensisFraas, 1913 as the type species of the genus Plateosaurus Meyer, 1837 by setting aside all previous fixations of type species for this nominal genus of sauropodomorph dinosaurs.

The International Commission on Zoological Nomenclature has suppressed for nomenclatural purposes the two-volume work “The White-cheeked geese: Branta canadensis, B. maxima, B. ‘lawrensis’, B. hutchinsii, B. leucopareia, and B. minima. Taxonomy, ecophysiographic relationships, biogeography, and evolutionary considerations” by Harold C. Hanson.

The International Commission on Zoological Nomenclature has conserved the usage of the specific name of Trochus (Osilinus?) capillaceusPhilippi, 1849 (currently Cantharidus capillaceus) by giving it precedence over its senior subjective synonym Trochus episcopus Hombron & Jacquinot, 1848.

The International Commission on Zoological Nomenclature has conserved the specific name of Bolitophagus cornutusFabricius, 1801 (currently Bolitotherus cornutus) by giving it precedence over its senior subjective synonym Opatrum bifurcumFabricius, 1798.

The International Commission on Zoological Nomenclature has conserved the spelling of the specific name of Lema decempunctataGebler, 1829. The name was originally published as “L. ropunctata”, but prevailing usage is of the spelling decempunctata as the former has been regarded by most subsequent taxonomists as a typesetting error.

The International Commission on Zoological Nomenclature has conserved the binomen Quetzalcoatlus northropi for a species of pterosaur that is the largest known flying organism, by ruling that both the generic name QuetzalcoatlusLawson, 1975 and specific name northropiLawson, 1975 are available and take authorship from Lawson, 1975.

The International Commission on Zoological Nomenclature has conserved the specific name of Thamnophilus schistaceusd’Orbigny, 1838 for a species of antshrike by suppressing the name Thamnophilus schistaceusd’Orbigny 1835, a senior primary homonym.

The International Commission on Zoological Nomenclature has conserved the specific name of Cetonia marmorea Olivier, 1789 (currently Gymnetis marmorea) by giving it precedence over its senior subjective synonym Scarabaeus pulcher Swederus, 1787.

One of the most iconic tortoise species, coming from the Sivalik Hills in India and probably the largest tortoise that ever lived, has a complicated nomenclatural history. Although initially published as Megalochelys sivalensis, the same authors decided to replace the name a few years later as Colossochelys atlas, starting a discussion on the proper nomenclature of this species that continues to date. I briefly review the original information and conclude that the original combination Megalochelys sivalensis is available under the International Code of Zoological Nomenclature and should be considered as the valid name for the Sivalik's Tortoise.

The purpose of this application, under Articles 23.9.3 and 81.2.3 of the Code, is to suppress ColonychusHarold, 1868 for the purposes of the Principle of Priority and thereby conserve Streblopus Lansberge, 1874 as the valid name of the genus of dung beetles consisting of S. opatroides Lansberge, 1874 and S. punctatus (Balthasar, 1938), in accord with universal current usage. Although made available by Harold in 1868, almost all authors who have cited the name Colonychus have regarded it as unavailable or invalid in favour of Streblopus, the only dissenting author having merely mentioned Colonychus twice in passing more than a century ago. Because no specific name has ever been used in combination with Colonychus, no type species has been fixed for this nominal genus. Nonetheless, our confirmation of the identity of a specimen presumably studied by Harold for his description of Colonychus leaves no doubt that the synonymy between Colonychus and Streblopus is correct. While the conditions of Art. 23.9.1.2 for automatic reversal of precedence are fully met, those of Art. 23.9.1.1 are not; therefore, recourse to the Commission's plenary power is necessary in this instance to maintain nomenclatural stability and universality.

The purpose of this application, under Article 55.3.1 of the Code, is to remove the homonymy between two family-group names of Hexapoda: the coleopteran tribal name AcalyptiniThomson, 1859 (type genus AcalyptusSchönherr, 1833; family Curculionidae) and the heteropteran tribal name AcalyptiniBlatchley, 1926 (type genus AcalyptaWestwood, 1840; family Tingidae). We propose to adopt the entire type genus name AcalyptaWestwood, 1840 as the stem for the corresponding family-group name AcalyptainiBlatchley, 1926. The senior homonym AcalyptiniThomson, 1859 (Coleoptera), based on AcalyptusSchönherr, 1833, will remain unchanged.

The purpose of this application, under Article 23.9.3 of the Code, is to conserve use of the generic name PachnaeusSchoenherr, 1826 (Curculionidae, Entiminae, Eustylini). The name Pachnaeus is threatened by its senior objective synonym, DocorhinusSchoenherr, 1823, for which it was erroneously erected as a replacement name. Strict application of the Code would result in unnecessary confusion since the name Pachnaeus has been heavily used in the agricultural and taxonomic literature for the last 193 years, whereas its senior objective synonym Docorhinus has been treated as valid only once since it was (erroneously) replaced by Pachnaeus. Several members of Pachnaeus, for example Pachnaeus opalus (Olivier, 1807) (“northern citrus root weevil”, for which a lectotype is designated herein), Pachnaeus litus (Germar, 1824) (“southern citrus root weevil”), and Pachnaeus citriMarshall, 1916, are well documented and serious pests of citrus. Reverting the genus name to its senior synonym would lead to nomenclatural instability and confusion in the literature and, because of the singular treatment of Docorhinus as valid. Prevailing usage (Arts. 23.9.1 and 23.9.2) cannot be invoked to resolve this discrepancy. We therefore request a reversal of precedence under the Commission's plenary power, with Docorhinus, the senior objective synonym, being suppressed.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the specific names of two species of agriculturally important cochineal scale insect, Dactylopius coccus Costa, 1829 and Dactylopius tomentosus (Lamarck, 1801), by suppressing the senior subjective synonyms Coccus sativusLancry, 1791 and Coccus mexicanusLamarck, 1801 for the former, and Coccus silvestrisLancry, 1791 for the latter.

The International Commission on Zoological Nomenclature has conserved the specific name Prionocerus bicolorRedtenbacher, 1868 for a species of soft-winged flower beetle (Cleroidea, Prionoceridae) by giving it precedence over its senior subjective synonym Prionocerus pertiiLaporte, 1836.

The International Commission on Zoological Nomenclature has used its plenary power to designate a neotype for Tipula contaminata Linnaeus, 1758, conserving the existing usage of Ptychoptera Meigen, 1803 and Ptychopteridae Osten Sacken, 1862.

The International Commission on Zoological Nomenclature has conserved the generic name DimetrodonCope, 1878 by giving it precedence over its senior subjective synonym BathygnathusLeidy, 1853.

The widely known and ecologically important sea star species, Luidia clathrata, was originally named Asterias clathrata by Say, 1825. This name is a junior homonym of Asterias clathrataPennant, 1777. The senior homonym has not been used as a valid name since 1899, fulfilling Article 23.9.1 of the Code, which reverses the priority of Asterias clathrataSay, 1825 over its senior homonym Asterias clathrataPennant, 1777. Here, in accordance with Article 23.9.2, we declare Asterias clathrataSay, 1825 a nomen protectum and Asterias clathrataPennant, 1777 a nomen oblitum.