The purpose of this application, under Articles 23.2 and 23.9.3 of the Code, is to conserve the usage of the genus-group name Cognettia Nielsen & Christensen, 1959 (enchytraeidae, Oligochaeta, Annelida) for a genus of annelid worms (type species Pachydrilus sphagnetorum Vejdovský, 1878 (‘1877’)). Cognettia, a name for a Holarctic genus of terrestrial and semi-aquatic annelid worms, is threatened by two subjective senior synonyms, Euenchytraeus Bretscher, 1906 and Chamaedrilus Friend, 1913. If these two names are considered synonyms, Euenchytraeus will replace Cognettia; if they are considered to represent two different genera, Chamaedrilus will replace Cognettia. In 2015 Martinsson et al. adopted the latter course, replacing Cognettia by Chamaedrilus, and allocated its species between both Euenchytraeus and Chamaedrilus. Cognettia is a widely used name and is well-known in the fields of soil biology, ecology, and ecotoxicology, and we propose it be given precedence over Chamaedrilus and Euenchytraeus, which had not been used as valid for almost a century.

The purpose of this application, under Article 23.9.5 of the Code, is to conserve the specific name of the terrestrial snail Bulimus rupestris Philippi, 1836 (currently Rupestrella rupestris, chondrinidae), originally published as a junior primary homonym of Bulimus rupestris Krynicki, 1833 (currently classified in the genus Peristoma, enidae) by ruling under the plenary power to disregard their primary homonymy.

The purpose of this application, under Articles 65.2.2 and 70.2 of the Code, is to fix Alaba cerithidioides Dall, 1889 as type species of Alabina, as originally intended by Dall. Alabina Dall, 1902 (Gastropoda), is a replacement name for Elachista Dall & Simpson, 1901, non Elachista Treitschke, 1833 (Insecta). The name Elachista was introduced inadvertently a few weeks before its intended publication, with the consequence that its type species by monotypy is Bittium californicum Dall & Bartsch, 1901. Dall had intended it to be Alaba cerithidioides Dall, 1889, and he cited that species as type of Alabina in several publications. Bittium californicum Dall & Bartsch, 1901, and Alaba cerithidioides Dall, 1889, are not congeneric and not even confamilial.

The purpose of this application, under Article 23.9.5 of the Code, is to conserve the specific name Phrynus mexicanus Poinar & Brown, 2004 which was proposed for a fossil whip spider (Arachnida, Amblypygi, phrynidae) preserved in Chiapas (Mexican) amber. This fossil species was initially described under the grammatically erroneous combination Phrynus mexicana. However, correcting the species epithet to mexicanus renders it a junior primary homonym of a Recent Mexican whip spider, Phrynus mexicanus Bilimek, 1867. The Recent species was subsequently transferred to the genus Paraphrynus Moreno, 1940, to give the current combination Paraphyrnus mexicanus (Bilimek, 1867), and neither species has ever been considered congeneric with the other.

The purpose of this application, under Article 23.9.3, is to conserve current usage of the well-established genus-group name Cryptodacus Hendel, 1914 for a genus of Neotropical fruit flies by suppression of the earlier, unused name Cryptodacus Gundlach, 1862, currently a junior synonym of Arrhyton Günther, 1858, a genus of snakes, under the plenary power of the Commission, in the interest of nomenclatural stability. Cryptodacus Gundlach has not been used as a valid name since 1883, whereas Cryptodacus Hendel has been used in a significant body of literature relating to fruit fly systematics, morphology and phylogeny and is the currently used name in various name and molecular databases.

The purpose of this application under Articles 78.1 and 81.1 of the Code is to suppress 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. Reasons for suppression are the work's many confounded new taxon designations, inappropriately chosen types, inadequately diagnosed new taxa, variable and confused authorships, and a flawed neotype designation. Together they serve as evidence of general nomenclatural dysfunction. If not suppressed, Hanson's work will become a source of destabilisation the nomenclature of the Branta canadensis complex.

Under the plenary power the Commission has conserved the name Ticinella primula Luterbacher, 1963, which is in prevailing use for a species of Early Cretaceous (Albian) planktonic foraminifera of the superfamily rotaliporoidea Sigal, 1958 (nom. correct. ex rotaliporacea) by suppressing its senior subjective synonym Hedbergella yezoana Takayanagi & Iwamoto, 1962.

The Commission has ruled under the plenary power that the specific name of the terrestrial snail Bulimus cylindricus Menke, 1828 (currently Brephulopsis cylindrica, enidae) is available despite being originally published as a junior primary homonym of Bulimus cylindricus Gray, 1825 (currently classified in the genus Macroceramus, urocoptidae).

The Commission has conserved the current usage of the generic name Phelister Marseul, 1853 for a well-established genus of histerid beetle by setting aside all previous type fixations for Phelister Marseul, 1853 preceding that of Phelister haemorrhous Marseul, 1853 by Kryzhanovskij & Reichardt (1976).

The Commission has conserved the specific name Onitis aeruginosus Klug, 1855, a junior primary homonym of Onitis aeruginosus Perty, 1830. Both names are in use today and have not been considered congeneric since 1859, when the senior homonym was transferred to the genus Gromphas Brullé, 1837. A third homonym, Onitis aeruginosus Gistel, 1831, which also has priority over Onitis aeruginosus Klug, 1855, but cannot be fixed to any species, has been totally suppressed for the purposes of the Principle of Priority and of the Principle of Homonymy.

The Commission has conserved the spelling of the buprestid beetle genus name Polybothris Dupont, 1833. The name was originally published as Polybotris but the spelling Polybothris has been in prevailing usage since 1900.

The Commission has reinstated as available the generic names Thyone Oken, 1815 and Psolus Oken, 1815, which were introduced by Oken (1815) in a work that was suppressed by the Commission in Opinion 417 because it was not consistently binominal. The names acquired availability from subsequent use by Lesson (1830) with concepts that differ completely from Oken's, and from the currently accepted usage of these names. Thyone and Psolus are among the most frequently used generic names in the Holothuroidea.

The Commission has not approved the application to emend the spelling Raja say Le Sueur, 1817 to Raja sayi Le Sueur, 1817. The original spelling is maintained.

The 2012 Amendment to the International Code of Zoological Nomenclature allows electronic publication for nomenclatural purposes if certain requirements are fulfilled. We here explain these simple requirements, including what needs to be registered in ZooBank and when, which version of an electronic work is potentially Code-compliant (only the final, immutable version), and what is the correct date of publication (that of the final, immutable version; pre-final versions posted online are preliminary and as such always unavailable). We advise registration in ZooBank of publications that are issued in both electronic and paper version to secure the nomenclatural priority of the generally earlier electronic version. Failure to update a ZooBank record after publication will not have any impact on availability under the Code but will keep the registered information hidden from public view. Publishers may want to consider automated registration as an integral part of the publishing process; this has already been shown to be feasible and would ease the burden of manual registration for editors and authors.

The question of the nomenclatural availability of preliminary electronic versions of taxonomic papers, distributed online ‘ahead of print’ by some journals and publishing companies, is addressed again. We disagree with Krell's suggestion to ‘distinguish between content and bibliographical metadata’. The concept of ‘bibliographical metadata’ does not exist in the Code and should not be incorporated into it. The citation of publication date, issue and page numbers are part of the relevant information that is useful in bibliographic references, in text citations and in synonymic lists that appear in taxonomic publications (which have a much longer life than most other publications), and should be considered part of the ‘content’ of a taxonomic paper. In particular, the page of first appearance of a name or of a nomenclatural act is traditionally cited in taxonomic revisions, monographs, faunas and catalogues, whether printed or stored in online databases, and this information is very useful for serious taxonomists. Having two different sets of information in this respect, in a first version of the work first published online but then discarded from the website of the journal, and in a subsequent one included into a journal issue, would be an indisputable source of confusion, which would not be solved by calling artificially both these versions the ‘version of record’ as if they were identical. The fact that ‘pagination is not regulated’ by the Code is fully irrelevant here: many aspects of taxonomic works are not regulated by the Code but are of crucial importance for the discipline of taxonomy. Krell's proposal is motivated, according to his own words, by some publishers’ desire to make their publications more ‘attractive as outlets of taxonomic research’. But the purpose of the Code is not to make some journals more attractive than others; it is to help working taxonomists in their daily work, to make it easier, more straightforward, efficient, reliable and useful, and less prone to ambiguity. We recommend rejecting Krell's suggestion. On the other hand, we make the new proposal of the creation of a ‘label’ to which some online journals and publishing companies might adhere, taking the engagement to publish online only one single version of each paper, with its final date, issue number and pagination. Authors will then have the possibility to choose their publication outlet among those having this label or those following the practice of ‘early view’. Currently, such preliminary versions of papers are unavailable under the 2012 Amendment of the Code.