Jubogaster, Parker & Maruyama, 2013

Parker, Joseph & Maruyama, Munetoshi, 2013, Jubogaster towai, a new Neotropical genus and species of Trogastrini (Coleoptera: Staphylinidae: Pselaphinae) exhibiting myrmecophily and extreme body enlargement, Zootaxa 3630 (2), pp. 369-378 : 375-376

Molecular phylogenetic placement of Jubogaster

While the head of Jubogaster is suggestive of Trogastrini , other characters typical of this tribe are absent. There is no dense genal beard of setae, the tarsal claws are both well-developed and equally-sized, rather than being unequal in size or consisting of one well-developed and one setiferous claw. A strongly-impressed median longitudinal sulcus on the pronotal disc is also lacking; although the sulcus is present, it is barely evident and only weaklydefined. Furthermore, the obcordate form of the pronotum, sharply constricted at the base, is far more similar to members of Jubini, another euplectite tribe.

Jubogaster ’s curious suite of features confounds a definitive assignment of the new taxon to tribe using morphology alone. To reliably place Jubogaster phylogenetically, we employed a non-destructive procedure to extract DNA from the type specimen, without damaging or altering its external morphology ( Gilbert et al. 2007). Using this approach, we successfully amplified a fragment of 28s rDNA from J. towai . This region is particularly informative for higher-level pselaphine systematics, resolving many relationships at the supertribal, tribal and subtribal levels (J. Parker and A. Vogler, unpublished data). We also sequenced this gene region from a range of other Pselaphinae including 5 genera of Trogastrini , 3 Jubini genera, and representatives of all other euplectite tribes except Metopiasini, Dimerini and Mayetiini. A variety of non-euplectite pselaphines from different supertribes were included, totalling 24 ingroup taxa. Three other staphylinids (from the subfamilies Proteininae , Euaesthetinae and Scydmaeninae ) and the silphid Silpha obscura were used as outgroups.

Both MP ( Fig 11 ) and Bayesian ( Fig 12 ) analyses placed Jubogaster within the Trogastrini with maximum support, forming a clade with Platomesus and Rhexius . This placement was recovered across all alignment parameter combinations tested with consistently high support. Although the taxonomic coverage is limited, Jubogaster emerges in the same position in a far more comprehensive analysis of>150 ingroup taxa, with extensive taxon sampling from almost all pselaphine tribes and subtribes (data not shown; J. Parker and A. Vogler, unpublished data). Hence, we conclude with a high degree of certainty that Jubogaster is indeed a member of Trogastrini .

Figures

FIGURES 11 – 12. Phylogenetic position of Jubogaster towai. Trees were rooted using Silpha obscura (Silphidae) as the designated outgroup. Grey branches denote outgroup taxa, black branches non-euplectite Pselaphinae, green branches Euplectitae, and purple branches Trogastrini. 11) Single most parsimonious tree of 2236 steps (CI = 0.50, RI = 0.56) found from an MP search on the default MUSCLE alignment. Values above branches are bootstrap proportions from 1000 replicates. ClustalX alignments made with a range of gap opening and extension costs produced highly similar topologies that differ only outside the Jubini + Trogastrini clade. 12) Bayesian consensus tree made from an unpartitioned analysis with the GTR + I + G model. Posterior probabilities for each node are shown above branches.