Coleoptera, Carabidae): Museum Rediscovery of a Relict Species from Samoa
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Zoosyst. Evol. 93 (1) 2017, 1–11 | DOI 10.3897/zse.93.10802 museum für naturkunde Bryanites graeffiisp. n. (Coleoptera, Carabidae): museum rediscovery of a relict species from Samoa James K. Liebherr1 1 Cornell University Insect Collection, John H. and Anna B. Comstock Hall, 129 Garden Ave., Cornell University, Ithaca NY 14853-2601 U.S.A. http://zoobank.org/4B7C702D-F9FC-4038-BE8E-DEC7FCD3D63A Corresponding author: James K. Liebherr ([email protected]) Abstract Received 14 October 2016 Bryanites graeffii sp. n. is described from Samoa based on a single male specimen col- Accepted 21 December 2016 lected between 1862–1870 that was recently discovered in the Muséum national d’His- Published 5 January 2017 toire naturelle, Paris. Cladistic analysis based on 127 morphological characters from 49 exemplars of the carabid beetle tribe Platynini in the Austral-Pacific region, places the Academic editor: new species as adelphotaxon to Bryanites samoaensis Valentine, type species of the genus Martin Husemann Bryanites Valentine, 1987. Bryanites comprises, along with Vitagonum Moore, 1998 of Fiji and Ctenognathus Fairmaire, 1843 of New Zealand, a clade that diverged early in Key Words the evolutionary history of Pacific platynine Carabidae. Bryanites graeffii exhibits very large body size among taxa of Platynini—16.2 mm standardized body length—with the anthropogenic extinction genus characterized by vestigial flight wings and metathoracic apomorphies that are asso- biogeography ciated with flight-wing loss. Along with Blackburnia Sharp, 1878 of Hawaii, the origins brachyptery of Bryanites, Vitagonum, and Ctenognathus are hypothesized to date to the Miocene, Polynesia with their radiations beginning long before the origins of the geographically widespread, flight-capable species of Metacolpodes Jeannel, 1948 that colonized numerous island systems across the western Pacific. Given the numerous platynine taxa collected by ex- tensive biotic surveys of Samoa during the first quarter of the 20th Century, the absence of any specimens of B. graeffii since the initial collection of the unique holotype prior to 1871 suggests that this species may be extinct. Such extirpation of large platynine cara- bid beetles has also been documented for Hawaii, where the time of extinction of seven Blackburnia species represented only by subfossil fragments coincides with the time of human colonization and attendant introduction of the Pacific rat,Rattus exulans (Peale). Introduction Pteropus Brisson, 1762 (Chiroptera: Pteropodidae), are known only from museum specimens collected between It is undeniable that natural history museums represent in- 1839 and 1856 (Helgen et al. 2009). In this contribution, valuable and irreplaceable archives of biological diversity a Samoan carabid beetle specimen collected prior to 1871, on Earth. Firstly these institutions serve as repositories for and subsequently deposited in the Paris Natural History many millions of studied and described specimens: i.e. type Museum, is shown to represent the only specimen known specimens and associated subsequent collections of named of a new species. Moreover, the genus to which the new species. Secondly museums also hold uncounted, unstud- species is assigned is known previously only from two spe- ied specimens that have been collected and processed, but cies based on two specimens collected in 1924 (Valentine never adequately examined or understood by a taxonomic 1987). That the new species is being described only now, specialist. Predictably, examination of unidentified materi- over 140 years after its collection from nature, attests to al collected long ago can produce surprising results, espe- the contextual information that is required to interpret bio- cially when the historical museum specimens represent the diversity, for it is not the simple naming of organisms that only evidence we have for existence of that particular spe- occupies systematists, but more importantly, the organized cies. For example, two Samoan species of flying fox, genus naming and placing in context of all organisms. A scientific Copyright James K. Liebherr. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 2 Liebherr, J.K.: Bryanites graeffii sp. n. name presented in isolation from any detailed taxonomic Thierry Deuve curators, and the B. P. Bishop Museum, framework is nearly useless, being suspect as a natural en- Honolulu (BPBM), James Boone collection manag- tity, devoid of biological context provided by knowledge er. Placement of the new species within the context of of its sister group (Hennig 1966), and at best representing platynine phylogeny (Suppl. material 1) utilized an up- a single datum indexing a gross estimate of biodiversity. dated version of the character matrix previously present- The specimen described in this contribution is a mem- ed in Liebherr (2005), with that paper citing institutional ber of the carabid beetle tribe Platynini belonging to the sources that provided specimens for initial matrix de- genus Bryanites Valentine, 1987 (Valentine 1987). This velopment. Taxa included in the analysis are distributed genus was previously known only from specimens collect- in the southwest Pacific region, including Australia and ed by E. H. Bryan, Jr., 23-v-1924, at Salaʽilua, Savaiʽi Is- Asia, northeastward through Melanesia and Polynesia to land, Samoa. Though the holotype specimens of Bryanites the Hawaiian Islands. samoaensis Valentine and B. barri Valentine are assign- Several taxa were added to complement the previous able to the Platynini, they are aberrant representatives of analysis. Colpodes kanak Fauvel (Fauvel 1903) of New that tribe. In contrast to many platynine carabid beetles, Caledonia was added to the analysis based on examina- which as the name suggests are flattened dorsally, the bod- tion of a female (MNHN) determined by Fauvel in 1906. ies of Bryanites beetles are fusiform with a broad prono- Vitagonum apterum Moore of Fiji was added because it, tum, their bodies convex dorsally. The two Bryanites spp. like Bryanites, represents an aberrant, taxonomically iso- also exhibit patterns of setation on the elytra and pronotum lated platynine lineage in the Pacific (Moore 1998). The unusual among platynine taxa. H. E. Andrewes, formerly male holotype of Bryanites samoaensis serves to repre- at the Natural History Museum, London and a worldwide sent the genus in the analysis. The female holotype of B. authority on Carabidae, placed determination labels on barri Valentine was also studied, and external anatomy of both specimens subsequently described by Valentine that prothorax and elytra is consistent with Valentine’s (1987) read “? Pterostichini gen. nov.” He did this presumably taxonomic decision placing both species together in the because the specimens appear superficially like the larg- genus. However the type specimen of B. barri is heavily er-bodied, more robust beetles of that tribe, though their damaged. The beetle was extensively disarticulated during lack of a critical diagnostic feature of most Pterostichi- description, demonstrated by Valentine’s illustrations of ni—i.e. an externally visible plica, or fold, along the apical an isolated mentum, maxilla, and labium (Valentine 1987: elytral margin—fits members of the tribe Platynini. An- Fig. 3). The resulting disarticulated structures were then drewes’ tentative, incorrect guess as to tribal membership mounted on two acetate sheets using Canada balsam as a is also understandable because the two Bryanites beetles fixative. Several isolated flecks of mounting medium -re appear nothing like the other Samoan species of Platynini main on the sheet without any associated sclerite, suggest- that he had previously described (Andrewes 1927). ing strongly that flexure of the acetate caused the balsam This paper first traces the provenance of the newly to pop off the acetate. This interpretation explains the ab- described Samoan beetle specimen from its collection in sence of the head capsule, mandibles, and antennae from nature to the present day. We cannot be certain why the the mounting cards. The female ovipositor is also damaged specimen avoided description until now. But the docu- and the internal reproductive tract not present. Given this mented timing of expeditions and subsequent taxonomic destruction of the specimen, 26 characters of the female publications coupled with the temporal connections of reproductive tract and 11 characters of the head cannot be the various taxonomists, and how the beetle could have scored. Coupling that loss with the inability to score the passed from hand to hand, make a strong case for how 21 characters of the male reproductive system from the a large carabid beetle from a tropical island could be ig- female holotype leads to at least 58 of the 127 characters nored for well over a century to be rediscovered within a necessarily being coded as missing. The poor mounting natural history museum. In order to be certain how best to condition of the remaining sclerites cemented to the spec- classify the new species, cladistic analysis using morpho- imen cards limits confidence in assessing microsculpture logical characters is used to phylogenetically place the covered by the Balsam, adding further uncertainty to the species. After adding the new species to a little-known assessment of character