Research Article |
Corresponding author: Tomáš Lackner ( lackobelansky@mac.com ) Academic editor: Michael Caterino
© 2017 Tomáš Lackner.
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.
Citation:
Lackner T (2017) Redescription of the enigmatic neotropical inquiline Paramyrmetes foveipennis Bruch, 1929 with notes on myrmecophily (Coleoptera, Histeridae) in the Saprininae subfamily. ZooKeys 675: 57-73. https://doi.org/10.3897/zookeys.675.12690
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The poorly-known and highly autapomorphic myrmecophilous Neotropical taxon Paramyrmetes foveipennis Bruch, 1929 is redescribed, figured and its lectotype designated. Notes on the evolution of the inquilinous lifestyle (myrmecophily) in the subfamily Saprininae are given.
Coleoptera , Histeridae , myrmecophily, Paramyrmetes , Saprininae
Several years ago the first higher-level phylogeny of the Saprininae was published, where all but three genera and subgenera of this subfamily were included (
In this paper, Paramyrmetes is re-described based on the type material. Habitus images as well as drawings of male genitalia are provided. This work represents another contribution to the systematics and higher taxonomy of the Saprininae (see e.g.
A dry-mounted syntype of Paramyrmetes foveipennis was relaxed in warm water for several hours. After removal from the original card, it was side-mounted on a triangular point and examined under a Nikon 102 binocular microscope and viewed with diffuse light. Male genitalia were first macerated in 10% KOH solution for about 3 hours, cleared in 80% alcohol and macerated in lactic acid with fuchsine, incubated at 60 ºC for another 30 minutes, and subsequently cleared in 80% alcohol and then observed in α-terpineol in a small dish. Digital photographs of male genitalia were taken by a Nikon 4500 Coolpix camera and edited in Adobe Photoshop CS5. Genitalia drawings based on the photographs, or direct observations were produced with the aid of Hakuba klv-7000 light box. Habitus photographs were taken by F. Slamka (Bratislava, Slovakia). The specimen was measured with an ocular micrometer. Beetle terminology follows that of
The specimen examined for this study is deposited in the following collection:
Abbreviations. Abbreviations of morphological measurements follow
APW width between anterior angles of pronotum
EL length of elytron along elytral suture
EW maximum width between outer margins of elytra
PEL length between anterior angles of pronotum and apices of elytra
PPW width between posterior angles of pronotum.
Paramyrmetes Bruch, 1929: 421. Type species Paramyrmetes foveipennis Bruch, 1929: 422, by monotypy.
Paramyrmetes
:
Medium-sized reddish-brown shining asetose Saprininae beetle with completely punctate and shagreened dorsal cuticle, broadly rectangular head; frontal and supraorbital striae absent, labrum tongue-shaped. Dorsal elytral striae strongly reduced; apical third of elytra deeply depressed; metaventrite and first visible abdominal ventrite with (striolate) depression. Pygidium with prominent round ornamentation; tibiae dilated.
Based on the autapomorphies outlined above, Paramyrmetes cannot be confused with any currently known South American Saprininae genus. The overall body coloration, in combination with the depressed apical third of the elytra, metaventral and abdominal depressions and, especially the peculiarly-shaped labrum, will readily set this taxon apart from the other members of the subfamily. Moreover, Paramyrmetes possesses pygidial ornamentation in the male sex. Pygidial ornamentation occurs in the Saprininae subfamily rather seldom, and was observed so far only with female specimens of several taxa (e.g. Euspilotus (Neosaprinus) perrisi Marseul, 1872)). According to my knowledge, male pygidial ornamentation has not been reported in the Saprininae subfamily hitherto.
The type series was found inside the refuse chambers of the ant Pogonomyrmex serpens Santchi, 1922. This species is apparently a specialised ant inquiline.
Known only from the type series collected in the province of Santa Fé, Argentina (Fig.
Although
Paramyrmetes
foveipennis
Bruch, 1929: 422, figs 1–5, 11;
Lectotype, present designation, ♂, side-mounted on a triangular mounting card, genitalia dismembered, glued to a separate card under the specimen, with the following labels: “Hersilia / “La Geraldina”” (written); followed by: “Prov.S.Fé.II.927 / J. Hubrich” (written); followed by: “con / Pogonomyrmex / v.carnivora” (written); followed by: “Phototypus” (light-green label, written); followed by: “Paramyrmetes / foveipennis / Bruch / C. BRUCH DETERM.” (printed-written); followed by: “ACHADO” (written); followed by: “Paramyrmetes / foveipennis / Bruch, 1929 / LECTOTYPE / Des. T. Lackner 2017” (red label, written) (
Body: PEL: 3.00 mm; PPW: 1.00 mm; APW: 2.00 mm; EW: 2.60 mm; EL: 1.70 mm. Body, including appendages reddish-brown (Figs
Prosternum: apical margin of prosternum (Fig.
Legs: protibia dilated, outer margin with approximately 14 short denticles, teeth lacking. Protibial spur thin, emerging near tarsal insertion, protarsal groove shallow. Mesotibia and metatibia not particularly dilated, outer margin with sparse denticles.
Male genitalia: 8th sternite (Figs
8 Paramyrmetes foveipennis Bruch, 1929, ♂, lectotype, terminalia: eighth sternite and tergite, ventral view 9 ditto, dorsal view 10 ninth and tenth tergites, lateral view 11 eighth sternite and tergite, lateral view 12 ninth and tenth tergites, dorsal view 13 spiculum gastrale (ninth sternite), ventral view 14 ditto, lateral view 15 aedeagus, dorsal view 16 ditto, lateral view.
In his catalogues
For the present study, I coded the morphological characters of Paramyrmetes and included them in the matrix used for my Satrapister paper (
Myrmecophily, or an ant-inquilinous lifestyle is rather rare among saprinine histerids and has hitherto been confirmed in six higher taxa with at least three independent evolutionary events leading to it (
I thank Gerardo Arriagada (Santiago de Chile, Chile) for his help acquiring the lectotype of Paramyrmetes foveipennis for my study. Funding for this study has been provided by the Alexander von Humboldt Foundation (Bonn, Germany), itself part of the Federal Ministry for Education and Research (Berlin, Germany). I thank Alexey K. Tishechkin (Washington D.C., USA), Peter W. Kovarik (Columbus, USA), William B. Warner (Chandler, USA) as well as the editor for the Histeroidea at ZooKeys for their critical comments and grammar correction of the manuscript. I thank my wife Pepina for re-drawing the figure from