The purpose of this application, under Article 23.9.3 of the Code, is to conserve the usage of Cryphalus saltuarius Weise, 1891 by reversing precedence with its subjective senior synonym Bostrichus asperatus Gyllenhal, 1813. Cryphalus saltuarius Weise, 1891 has been in consistent usage for more than 100 years. Accepting priority would create unnecessary confusion because Cryphalus asperatus (Gyllenhal) has a confused taxonomic history and little prior use as a valid name. Cryphalus abietis Ratzeburg, 1837 is removed from synonymy with Bostrichus asperatus Gyllenhal, 1813 and resurrected as valid, and Bostrichus asperatus Gyllenhal, 1813 is proposed as a senior synonym of Cryphalus saltuarius Weise, 1891, syn. n., and C. scriba Gozis, 1886, syn. n.

The purpose of this application, under Articles 23.9.3 and 81.2.2 of the Code, is to conserve the usage of the genus-group name Trilobatus Spezzaferri, Kucera, Pearson, Wade, Rappo, Poole, Morard & Stalder, 2015 for a genus of planktonic foraminifera from the global ocean and fossil record by partial suppression of its senior objective synonym Trilobigerina Popescu, 1987. Partial suppression of the little-used senior name will allow conservation of the younger name that is in very widespread use.

The purpose of this application, under Articles 23.9.3 and 81.1 of the Code, is to conserve the current usage of the specific name of the northeast Pacific Ocean marine mussel Mytilus californianus Conrad, 1837, the identity of which has never been questioned. After examining the type specimens of Mytilus zonarius Lamarck, 1819 and Mytilus canalis Lamarck, 1819, Huber (2010) concluded that they were M. californianus and used the former as its valid name. Neither Mytilus zonarius nor M. canalis have been used as the valid name of Mytilus californianus between 1819 and 2010. The name Mytilus californianus has been used as the valid name of this species in thousands of publications between 1837 and 2020. It is proposed to conserve the name Mytilus californianus Conrad, 1837 by reversal of precedence with the names Mytilus zonarius Lamarck, 1819 and Mytilus canalis Lamarck, 1819.

The purpose of this application, under Article 55.3.1 of the Code, is to remove the homonymy between the family-group name Stygnidae Handlirsch, 1906 (Arthropoda: Insecta: order incertae sedis) and the family-group name Stygnidae Simon, 1879 (Arthropoda: Arachnida: Opiliones). It is proposed that the stem of the generic name Stygne Handlirsch, 1906 be emended to Stygne- to give Stygneidae, while leaving the harvestmen family-group name Stygnidae, which is based on the genus Stygnus Perty, 1833, unaltered.

The purpose of this application, under Article 75.6 of the Code, is to conserve the current usage of the specific name superba for a species of bird-of-paradise from New Guinea by setting aside the neotype designated for Paradisea superba J.R. Forster, 1781 by Irestedt et al. in 2017 and instead deeming the later neotype designation by Elliott et al. in 2022 to be valid. The former neotype designation was not in accord with then-prevailing usage, as the taxonomic identity of Paradisea superba had remained unchallenged since its initial introduction 236 years previously.

The purpose of this application, under Article 75.6 of the Code, is to conserve the current usage of the combination Gymnocheta viridis (Fallén, 1810) for a species of Palaearctic tachinid fly by setting aside the existing holotype of Tachina viridis Fallén, 1810 and designating a neotype in its place. The holotype is not in taxonomic accord with the current usage of the name Gymnocheta viridis and is instead conspecific with the lectotype of Gymnocheta magna Zimin, 1958. Stability and universality will be threatened if the existing holotype of Gymnocheta viridis is not replaced by a neotype, because Gymnocheta viridis will become the valid name for Gymnocheta magna and a replacement name will be needed for the current Gymnocheta viridis.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the usage of the name Allosaurus Marsh, 1877, by designating specimen USNM 4734 as the neotype to replace the nondiagnostic holotype (YPM 1930) of Allosaurus fragilis Marsh, 1877. In their comment supporting Case 3506, Loewen & Chure (2010) specified the skeletal elements (attributable to a single individual) that should constitute the neotype.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the current usage of the specific names of Tipula marci Linnaeus, 1758 (currently Bibio marci) and Tipula febrilis Linnaeus, 1758 (currently Dilophus febrilis), by designating a neotype for each nominal species.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the specific names P arnassius phoebus (Fabricius, 1793) and Parnassius ariadne (Lederer, 1853) in their current usage, and to set aside all previous fixations of type specimens for the nominal species Papilio phoebus Fabricius, 1793, by designating the specimen INS_LEP_0000940 as the neotype.

The International Commission on Zoological Nomenclature has declined to use its plenary power to declare the pamphlet “Procrustomachia” 2016–2018 (Vols 1–3) as an unavailable work. As a result, names and nomenclatural acts published within it are not to be considered unavailable for that reason alone.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the names Bengalia jejuna (Fabricius, 1787) and Bengalia torosa (Wiedemann, 1819) in their accustomed usage, and to set aside three female syntypes of Musca jejuna Fabricius, 1787, and the male and female syntypes of Musca torosa Wiedemann, 1819, by replacing them with male neotypes.

The International Commission on Zoological Nomenclature has declined to use its plenary power to set aside all previous type fixations for the nominal species Petalodus hastingsii Owen, 1840, and to designate a neotype to replace what is considered a nondiagnostic holotype.

The International Commission on Zoological Nomenclature has used its plenary power to fix the authorship, date and type species of the genus-group name Lucerna Swainson, 1840, thereby conserving the current usage of both the aforementioned name and the family-group name Lucerninae Swainson.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the current usage of the specific name of Nebela militaris Penard, 1890, by granting it precedence over its senior subjective synonym, Nebela bursella Taránek, 1882.

The International Commission on Zoological Nomenclature has used its plenary power to designate Cnodalon viride Latreille, 1804 as the type species of Cnodalon Latreille, 1797, and rule that Cnodulon, as used by Fabricius (1801a, 1801b), is an incorrect subsequent spelling of Cnodalon Latreille, 1797.

The International Commission on Zoological Nomenclature has used its plenary power to emend the spelling of the family-group name Cepheidae Berlese, 1896 (Acariformes) to remove homonymy with Cepheidae Agassiz, 1862 (Cnidaria). The stem of the acariform generic name Cepheus Koch, 1835 has been emended to Cepheus- to give Cepheusidae Berlese, 1896, while the stem of the cnidarian generic name Cephea Péron & Lesueur, 1810 remains unaltered.

The International Commission on Zoological Nomenclature received an application to conserve the subjective junior synonym Helix dibothrion Bielz, 1860 (originally spelled H. dibotrion) by suppressing its senior subjective synonym Helix diodon Rossmässler, 1835, with the additional proposal that the prevailing spelling dibothrion (currently as Perforatella dibothrion) be deemed the correct original spelling of the specific name originally spelled dibotrion. This Case was not approved by the Commission, who acted under Art. 83 of the Code by setting aside the application of Art. 11.6.1 for the names Helix diodon Rossmässler, 1835 and Helix dibotrion Bielz, 1860, which thereby were not made available under Art. 11.6.1 but were made available as Helix bidens var. diodon Tryon, 1887 and Helix dibothrion Kimakowicz, 1884, in keeping with the traditionally applied precedence of dibothrion over diodon.

The International Commission on Zoological Nomenclature has used its plenary power to replace the unidentifiable female lectotype of Rhyncholepta grandicallosa Bergroth, 1911 with a male neotype.

The International Commission on Zoological Nomenclature has used its plenary power to suppress the generic name Colonychus Harold, 1868, a subjective senior synonym of Streblopus Lansberge, 1874, although no type species has been designated, to conserve and give precedence to the generic name Streblopus Lansberge, 1874, type species Streblopus opatroides Lansberge, 1874.

The International Commission on Zoological Nomenclature has used its plenary power to conserve the species-group name Ateuchus costatus Wiedemann, 1823, by not being invalid by reason of being a junior primary homonym of Ateuchus costatus Thunberg, 1818.

The International Commission on Zoological Nomenclature has declined to use its plenary power to reverse Opinion 2404 regarding Case 3633 which would have resulted in giving priority to the species-group name Dysactis pallida Agassiz in Verrill, 1864 (currently Exaiptasia pallida) over Dysactis diaphana Rapp, 1829 (currently Exaiptasia diaphana). As a result, the Ruling given in Opinion 2404 stands and the species-group name pallida Agassiz in Verrill, 1864, as published in the binomen Dysactis pallida, will not be given precedence over the species-group name diaphana Rapp, 1829, as published in the binomen Actinia diaphana, whenever the two are considered synonyms.

The authorship of the sauropod dinosaur genus Astrodon is frequently cited as Johnston, 1859, and its type species Astrodon johnstoni is usually cited as Leidy, 1865. Although Johnston's publication does satisfy the Code's requirements for published work, the lack of description means it does not satisfy the criteria of availability in Article 12 for names published before 1931. Astrodon was a nomen nudum until it was made available by Leidy in his subsequent description of the nominal genus with its single new nominal species. The correct authorship of both the genus Astrodon and its type species Astrodon johnstoni is therefore Leidy, 1865.

The kākāpō was named Strigops habroptilus by G.R. Gray in 1845. However, in recent decades authorities have begun to recommend habroptila as the correct species name through mistaken interpretation of gender agreement rules. Here, we explain that habroptilus remains the valid species name through correct application of the articles in the International Code of Zoological Nomenclature.

A new replacement name, nomen novum, is proposed for Myrmeleon croceus Michel & Akoudjin, 2023, which is an unreplaced junior primary homonym of Myrmeleon croceus Esben-Petersen, 1918.