†Japanolaccophilus Beatificus Sp. N. from Baltic Amber and a Key to the Laccophilinae Genera of the World (Coleoptera: Laccophilinae)

Zootaxa 4567 (1): 176–182 ISSN 1175-5326 (print edition) https://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2019 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4567.1.10 http://zoobank.org/urn:lsid:zoobank.org:pub:8EDA8A17-B5D6-4815-A43F-3490E8FB4E8D

†Japanolaccophilus beatificus sp. n. from Baltic amber and a key to the Laccophilinae genera of the World (Coleoptera: Laccophilinae)

MICHAEL BALKE1,2 & LARS HENDRICH1 1Zoologische Staatssammlung, Münchhausenstrasse 21, D-81247 München, Germany. E-mail: [email protected], [email protected] 2Corresponding author. E-mail: [email protected]

Abstract

We provide the first report of the subfamily Laccophilinae Gistel, 1848 from Baltic amber, based on a female specimen collected in Russia, Kaliningrad Region, Yantarnii (Jantarny) mine. This specimen represents a new species and could be assigned to the extant genus Japanolaccophilus Satô, 1972. To date this genus was monotypic with one species in Japan. The new species is here described as †J. beatificus sp. n. and compared with the extant Japanolaccophilus niponensis (Kamiya, 1939). We also provide a modified key to the Laccophilinae genera of the World, as we found minor errors or ambiguities in recent keys.

Key words: Dytiscidae, Laccophilinae, Japanolaccophilus, new species, Baltic amber, key to genera

Introduction

Diving beetles are rarely reported from amber. Described taxa include a few species based on adult specimens from the subfamilies Hydroporinae (placed in the genus Hydroporus Clairville, 1806), Copelatinae (placed in the genus Copelatus Erichson, 1832) and Agabinae (placed in the genus Hydrotrupes Sharp, 1882) (Miller & Balke 2003; Balke et al. 2010; Gómez & Damgaard 2014). Here, we provide the first report of the subfamily Laccophilinae Gistel, 1848 from amber, based on a female specimen from Baltic amber mined in the Kaliningrad region. Extant Laccophilinae consist of two tribes with 14 genera and about 450 species (Nilsson & Hajek 2018). Roughly half of the species are either strictly lotic, or to some degree associated with running waters. The new species is associated with the monotypic genus Japanolaccophilus Satô, 1972, with the only extant member being the running water species Japanolaccophilus niponensis (Kamiya, 1939) (Fig. 4), considered endangered and endemic to Japan (Okada 2009; Nilsson & Hajek 2018).

Materials and methods

The beetle was studied with a Leica M205C stereo microscope at 10–160x. Photographs were taken with a digital photo imaging system, composed of a Leica Z 6 APO and a Nikon V1 camera. Image stacks were aligned and assembled with the computer software Helicon Focus 4.77TM.

Taxonomy

Genus Japanolaccophilus Satô, 1972

Type species: Neptosternus niponensis Kamiya, 1939: 32.

176 Accepted by H. Fery: 15 Jan. 2019; published: 14 Mar. 2019 Diagnosis. Moderately large species of Laccophilinae (total length 3.0–3.2 mm), with the suture between elytron and epipleuron visible dorsally (Figs 3A, D); hind angles of pronotum rounded (Fig. 1); base of pronotum straight or almost so; prosternal process deltoid, not extending beyond mesocoxae and with single posterior tip in middle, not trifid (e.g. with three needle-like tips, like Neptune's fork) (Figs 4, 3C, F).

FIGURE 1. †Japanolaccophilus beatificus sp. n., dorsal view. Total length of beetle 3.0 mm.

Type locality. Russia, Kaliningrad Region, Yantarnii (Jantarny) mine, around 54.867N 19.971E. Age. Baltic amber is thought to be of middle Eocene age (Lutetian: 41.3–47.8 million years ago) (Wolfe et al. 2016). Holotype (female). In a plastic box in the main collection of the Zoologische Staatssammlung München (ZSM) with a printed label: "Baltic amber from the Yantarnii (Jantarny) mine in the Kaliningrad region, Russia, obtained from Marius Veta. HOLOTYPE †Japanolaccophilus beatificus sp. n. Balke & Hendrich det. 2018". Description. Beetle broadly ovate, length of beetle without head about 2.8 mm, with head about 3.0 mm; greatest width about 1.6 mm.

FIGURE 2. †Japanolaccophilus beatificus sp. n., frontal view with light in different angle.

Surface sculpture. Head with polygonal meshes and fairly dense larger punctation except on frons and clypeus (Figs 2A, B). Pronotum with polygonal meshes and fairly dense larger punctation (Fig. 1). Pronotum surface in part appearing slightly deformed. Elytron with polygonal meshes and fairly dense larger punctation (Figs 1, 3A, D). Profemur and tibia dorsally and ventrally with coarse punctation (Figs 2A, B, 3C, G). Mesofemur and tibia dorsally and ventrally with coarse punctation. Metafemur ventrally with longitudinal meshes; metatibiae ventrally with longitudinal meshes but no coarse punctation, dorsally with coarse punctation. Metatarsomeres

178 · Zootaxa 4567 (1) © 2019 Magnolia Press BALKE & HENDRICH without coarse punctation (Figs 3A, B). Metacoxa with microreticulation of long diagonal cells, and without obvious punctation (Figs 3C, G). Sternites II, III and less so IV with diagonal lines, V, VI and VII with increasingly distinct fine microreticulation and large setiferous punctation.

FIGURE 3. †Japanolaccophilus beatificus sp. n., (A) posterior portion of right elytron, hind femur and tarsus, (B) hind tarsus with light from different angle, (C) prosternum and midsection of body, (D) posterior portion of right elytron, (E) focus on last visible ventrite, (F) overview of ventral side, (G) focus on fore and middle legs as well as on metafemur.

JAPANOLACCOPHILUS BEATIFICUS SP. N. FROM BALTIC AMBER Zootaxa 4567 (1) © 2019 Magnolia Press · 179 Structures. Antennae filiform. Hind margin of pronotum almost straight, slightly concave in middle; hind angles broadly rounded. Prosternal process not extending beyond procoxae, broadened, somewhat deltoid (Figs 3C, F). Prosternal ridge not clearly visible, but possibly not with sharp ridge. Metaventrite also not well visible, lateral "wings" narrow. Metacoxal lines and metacoxal process not visible, this part of surface appearing deformed. Metatarsomeres with posteroapical margins weakly lobed compared to other Laccophilinae genera. Hind margin of sternite VII (= last visible ventrite) rounded, with fairly dense coarse setiferous punctation (Figs 3E, F). Differential diagnosis. The extant Japanolaccophilus niponensis has the metatibia and metatarsomeres dorsally and ventrally with distinct coarse punctation, which is not present in †J. beatificus sp. n.. The last ventrite appears more densely punctate in †J. beatificus sp. n. than in J. niponensis. Etymology. Latin adjective for "making happy", from beatum, happiness, in reference to the joyful discovery of this rare amber inclusion. The name is an adjective in the nominative singular. Distribution. Only known from the type locality near Kaliningrad, Russian Federation. This is the first record of the genus outside Japan. Habitat. Unknown. Assuming the dorsally visible suture between elytron and epipleuron is a derived character, this species would be member of a clade containing almost exclusively running water species (only one undescribed species of Neptosternus Sharp, 1882 from Timor was collected in large numbers in an intermittent stream pool, well away from running water). If †Japanolaccophilus beatificus sp. n. was also a running water species, its entrapment in resin might have occurred during a dispersal flight, or the species had a habitat other than related extant ones.

FIGURE 4. Japanolaccophilus niponensis, ventral side. Specimen from Nishitosa Village, Kochi Prefecture, Shikoku Island, Japan. Total length of beetle 3.1 mm.

180 · Zootaxa 4567 (1) © 2019 Magnolia Press BALKE & HENDRICH Note. In Toledo & Michat (2015), Japanolaccophilus is diagnosed as with lateral sides "not bordered in dorsal view", but this is not correct. Other genera with a dorsally well visible suture are the lotic American Laccodytes Régimbart, 1895, as well as the Afrotropical-Oriental-East Palearctic Neptosternus Sharp, 1882; the suture is faintly visible in the lotic New Guinean Philaccolilus Guignot, 1937. In the key of Miller & Bergsten (2016), Japanolaccophilus is in a group of genera diagnosed as having the posteromedial margin of pronotum angulate, but this is not really the case. Although there is a very subtle angle, we would describe the hind margin as "straight or almost so". Additional material examined for comparison. Japanolaccophilus niponensis (Kamiya, 1939): 1 female: "JAPAN Kotchi-pref. Nishitosa vil. Kuroson 3 May 1992 M. Mori leg." (ZSM).

Modified key to Laccophilinae genera (based on Toledo & Michat 2015)

1. Metatibiae with a single apical spur; antennal segments enlarged and flattened in male. Neotropical...... Napodytes - Metatibiae with 2 apical spurs; antennal segments never enlarged or flattened in male ...... 2 2. Suture between elytron and epipleuron visible dorsally (= "lateral sides bordered": in dorsal view elytra visibly outlined by a fine border along outer lateral side)...... 3 - Suture between elytron and epipleuron not visible dorsally (= "lateral sides not bordered": in dorsal view the elytra do not appear to be bordered)...... 6 3. Hind angles of pronotum rounded...... 4 - Hind angles of pronotum extending posteriorly into acuminate spine; prosternal process long, extending beyond mesocoxae. 5 4. Base of pronotum projecting hindwards in a distinct angle at middle; pro and mesotibia and femur at most with fine punctation. Neotropical ...... Laccodytes phalacroides-group - Base of pronotum straight or almost so; fore and middle tibia and femur with dense, coarse punctation. Palearctic...... Japanolaccophilus 5. Prosternal process trifid; posterolateral lobes of metatarsi very short, almost lacking; apex of elytra rounded. Afrotropical and Oriental...... Neptosternus - Prosternal process simple; posterolateral lobes of metatarsi longer, well developed; apex of elytra truncate. Neotropical...... Laccodytes apalodes-group 6. Metatibial spurs bifid apically (except in L. bapak Balke, Larson & Hendrich, 1997 from Papua New Guinea). Worldwide ...... Laccophilus - Metatibial spurs simple, apically acute ...... 7 7. Base of pronotum projecting hindwards in a distinct angle at middle ...... 8 - Base of pronotum straight or almost so...... 11 8. Prosternal process laterally compressed behind procoxae ...... 9 - Prosternal process fairly broad behind procoxae ...... 10 9. Length not exceeding 5 mm; pro- and mesofemora and tibiae densely punctate; prosternal process markedly carinate. Tibet...... Laccoporus - Length exceeding 5 mm; pro- and mesofemora and tibiae never densely punctate; prosternal process slightly carinate. Africa ...... Philodytes 10. Mesotibial spurs not longer than segments 1–2 of mesotarsi combined; elytra covered by numerous, more or less impressed punctures. Oriental...... Laccosternus - Mesotibial spurs longer than segments 1–4 of mesotarsi combined; elytra lacking punctures, at most bearing very few, small, hardly visible punctures. Neotropical and SE Nearctic...... Laccomimus 11. Reticulation on elytra consisting of longitudinal or broad polygonal meshes; metacoxal lines fairly parallel. Afrotropical...... Africophilus - Reticulation on elytra consisting of small, transversal meshes; metacoxal lines more or less convergent anteriorly...... 12 12. Space between metacoxal lines strongly rugose-punctate; metacoxal processes with round meshes and distally bilobed. Austra- lia...... Australphilus - Space between metacoxal lines somewhat smooth; metacoxal processes reticulate with transversal meshes and distally not bilobed...... 13 13. Metacoxa with stridulatory file; posterolateral lobes of metatarsi short; ventrite 6 in females rounded apically. Afrotropical...... Philaccolus - Metacoxa lacking stridulatory file; posterolateral lobes of metatarsi very long; ventrite 6 in females with an apical lobe, more or less developed. Papua New Guinea...... Philaccolilus

Acknowledgements

We thank Marius Veta (Palanga, Lithuania) for information on the type locality, and for providing this interesting beetle for us to study.

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