Arachnologische Mitteilungen 54

Arachnologische Mitteilungen / Arachnology Letters 54: 24-27 Karlsruhe, September 2017 The genus Arboricaria was established by Bosmans (in Bos- mans & Blick 2000) for the three species of the subopaca group of Micaria defined by Wunderlich (1980) and two newly described species. No explicit justification was provi- ded for the decision to place this particular species group, but not others, in its own genus, and the status of the new genus has been controversial from the beginning. Platnick, as or- ganizer of the World Spider Catalog and previous reviser of the Nearctic members of Micaria (Platnick & Shadab 1988), rejected the genus, “as [Bosmans] provided no evidence wha- tever that these taxa [included in Arboricaria ] constitute the sister group of all other Micaria , or that the remaining Mica- ria do not constitute a paraphyletic group from which a rela- tively autapomorphic subgroup has been artificially extracted” (Platnick 2014), thus effectively synonymizing Arboricaria with Micaria . In this assessment he was followed by Wunder- lich (2017), an earlier reviser of the Palaearctic Micaria spe- cies (Wunderlich 1980), who formalized the synonymy and concluded that Arboricaria should be considered as a “species- group of Micaria or as a subgenus”. In contrast, Mikhailov (2016) argued with reference to the International Code of Zoological Nomenclature that “there are no formal grounds to reject the validity of Arboricaria “, and consequently the ge- nus is considered as valid in the latest version of the World Spider Catalog (WSC 2017). However, just like Bosmans, Mikhailov failed to provi- de unambiguous synapomorphies for the remaining 100 or so species of Micaria , so that Platnick’s concerns about the potential paraphyly of Micaria sensu stricto remain unresol- ved.The formalistic argument based on the regulations of the ICZN is obviously insufficient. As Minelli & Kraus (1999) as president and former president of the International Commis- sion on Zoological Nomenclature explain in their Preface to the Fourth Edition of the Code “[t]he conventional Linnaean hierarchy [embodied in the Code] will not be able to survive alone: it will have to coexist with the ideas and terminology of phylogenetic (cladistic) systematics”, stating explicitly that the traditional nomenclature can be perceived as “too permis- sive, in so far as it may be equally applied to paraphyletic as to monophyletic groups.”This is exactly the issue at hand: while Arboricaria is quite likely to be a monophyletic group, the re- sulting truncated Micaria could equally likely be paraphyletic. As has been elaborated extensively, following the historical debate between Ernst Mayr (1974) and Willi Hennig (1975), paraphyletic taxa are non-monophyletic, differ only in subtle ways from polyphyletic ones (Platnick 1977), and have argua- bly no useful place in a phylogenetic taxonomy and nomen- clature. The recent availability of large amounts of DNA barco- ding data for spiders (e.g., Astrin et al. 2016, Blagoev et al. 2013, 2016) now offers a unique opportunity to resolve this issue: a sufficiently large number of Micaria species, as well as sequences for an undisputed member of Arboricaria, A. subopaca (Westring, 1861), have been made publicly available for phylogenetic analysis to answer Platnick’s key question: is Arboricaria the sister group of all other Micaria , or does its extraction leave Micaria sensu stricto as a paraphyletic group? Material and methods The results presented below are based entirely on the use of public datasets, analysed using freely available tools with easy and intuitive user interfaces, not requiring programming skills. While the correct use and interpretation of the output of these tools depends on some understanding of sequence alignments and molecular phylogeny, the type of analysis pre- sented here should be widely accessible to practicing spider taxonomists in general. All public DNA barcode sequences (based on the mi- tochondrial cytochrome c oxidase I gene, COI) for Micaria and Arboricaria species represented by Barcode Index Num- bers (Ratnasingham & Hebert 2013) in the BOLD database (Ratnasingham & Hebert 2007) as of 21 February 2017 were downloaded in FASTA format, together with a random selec- tion of single sequences for a diverse range of other gnaphosid species to be used as an outgroup (including representatives of Callilepis, Cesonia, Drassyllus, Gnaphosa, Haplodrassus, Her- pyllus, Nodocion, Nomisia, Orodrassus, Parasyrisca, Scotophaeus, Sergiolus, Sosticus and Zelotes ). Sequences were managed in BioEdit v7.2.5 (Hall 1999), which was also used for explo- ratory sequence alignment using ClustalW 1.4 (Larkin et al. Public DNA barcoding data resolve the status of the genus Arboricaria (Araneae: Gnaphosidae) Rainer Breitling doi: 10.5431/aramit5405 Abstract. An analysis of public DNA barcoding data confirms that the extraction of Arboricaria Bosmans, 2000 from the genus Micaria Westring, 1851 would require the division of Micaria into at least five (and probably more) individual genera, to restore the monophyly of Micaria sensu stricto. Such an excessive splitting of a homogenous and well-defined genus would be neither desirable nor practical, and consequently Arboricaria should be considered a subjective junior synonym of Micaria , as suggested earlier ( syn. conf. ) . Keywords: Araneae, DNA barcoding, cladistics, phylogenetic systematics, paraphyly, spider. Zusammenfassung. Öffentliche DNA-Barcode-Daten klären den Status der Gattung Arboricaria . Eine Analyse von öffentlich zu- gänglichen DNA-Barcode-Daten bestätigt, dass die Herauslösung von Arboricaria Bosmans, 2000 aus der Gattung Micaria Westring, 1851 eine Aufteilung von Micaria in mindestens fünf Einzelgattungen erfordern würde, um die Monophylie der Restgattung Micaria im enge- ren Sinne wiederherzustellen. Diese exzessive Aufteilung einer homogenen und klar definierten Gattung wäre weder wünschenswert noch praktikabel, und folglich sollte Arboricaria , wie bereits früher vorgeschlagen, als subjektives jüngeres Synonym von Micaria behan- delt werden ( syn. conf. ) . Rainer Breitling, Faculty of Science and Engineering, University of Manchester, Manchester M1 7DN, UK; E-mail: rainer.breitling@manchester.ac.uk submitted 4.4.2017, accepted 14.7.2017, online 21.7.2017