Research 100 (2019) 126e133

Contents lists available at ScienceDirect

Cretaceous Research

journal homepage: www.elsevier.com/locate/CretRes

Short communication yCretohlezkus gen. nov. from Upper Cretaceous demonstrates ancient origins of suctorial mouthparts in (Coleoptera: )

Paweł Jałoszynski

Museum of Natural History, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland article info abstract

Article history: Eucinetidae is a small family comprising only ten extant genera. Five of them have unusually Received 14 January 2019 modified mouthparts with a strongly transformed labium, which shows features interpreted as adap- Received in revised form tations to suctorial feeding. Among the hyperdiverse Coleoptera, similar feeding adaptations are known 21 February 2019 only in several genera of Cerylonidae and Leiodidae. Fossils attributed to Eucinetidae or representing taxa Accepted in revised form 18 March 2019 presumably closely related to eucinetids are known from Lower Cretaceous of China and Upper Available online 23 March 2019 of Mongolia, but none of them shows modified mouthparts. The first fossil of a ‘suctorial eucinetid’, yCretohlezkus alleni gen. et sp. nov., is reported in the present paper, based on a well-preserved specimen Keywords: y Fossil in Burmese amber. A preliminary phylogenetic analysis placed Cretohlezkus near base of ‘ ’ Beetle the monophyletic suctorial eucinetid lineage, but branch support was too low to present a robust Myanmar evolutionary hypothesis. The prementum of yCretohlezkus is modified as strongly as that of extant Cenomanian members of this group, demonstrating early origins of still only speculative feeding habits of the ‘suc- torial eucinetids’, which presumably use Myxomycetes or Basidiomycetes as the source of food. © 2019 Elsevier Ltd. All rights reserved.

1. Introduction The scirtoid family Eucinetidae is a small group that comprises less than 50 extant species classified in the extant genera Bisaya The huge order of Coleoptera or is characterized by Reitter, 1884, Eucilodes Vít, 1985, Eucinetella Nikitsky, 1996, Euci- biting mouthparts, and exceptions from the groundplan are not netus Germar, 1818, Euscaphurus Casey, 1885, Jentozkus Vít, 1977, very common. However, some highly specialized modifications are Noteucinetus Bullians & Leschen, 2004, Latreille, 1829, known, most notably a suctorial feeding apparatus, which has Proeuzkus Vít, 2000, and Tohlezkus Vít, 1977 (Leschen, 2016, and independently evolved in phylogenetically distant groups, as Myr- later additions). They can be readily distinguished by a fusiform micholeva Lea, 1910 (: Leiodidae), several genera of body form and large metacoxal plates that cover most of the met- Cerylonidae (), e.g., Cautomus Sharp, 1885 and Rostror- aventrite (Leschen, 2016). Eucinetids are cryptic beetles, usually ylon Slipinski, 1991 (Cerylonidae), and several genera of scirtoid collected by sifting leaf litter, under bark of trees or in rotten wood; Eucinetidae (Leschen, 2016). Interestingly, even though these some species have been found in association with Myxomycetes or modifications are unusual and highly interesting, their morphology Basidiomycetes, on which the adults and larvae supposedly feed remains exceptionally poorly characterized, and almost nothing is (Leschen, 2016). Adults of some species can also be collected by known about actual function of structures that form the piercing- pitfall traps in sandy and relatively dry xerothermous habitats sucking apparatus. Even the source of food for these beetles has (Jałoszynski, pers. obs.). not been confirmed yet (e.g., Newton, 2016), and the question when The most unusual feature of eucinetid beetles is a high pro- such adaptations have originated remains open. portion of taxa with strongly modified adult mouthparts, with the anterior portion of the labium (i.e., the prementum) strongly elongate, subtriangular, and presumably functioning as a piercing device. Leiodidae with ~380 genera (Newton, 2016) have only one Abbreviations: cPJ, collection of Paweł Jałoszynski, Wrocław, Poland; MNHW, genus with piercing-sucking mouthparts, and among 52 genera of Museum of Natural History, University of Wrocław, Wrocław, Poland. Cerylonidae there are only six genera with a strongly elongate, E-mail address: [email protected]. https://doi.org/10.1016/j.cretres.2019.03.016 0195-6671/© 2019 Elsevier Ltd. All rights reserved. P. Jałoszynski / Cretaceous Research 100 (2019) 126e133 127

clearly suctorial labium (Slipinski, 1991). The development of suc- Tohlezkus rufus (Sakai, 1980) (Japan; cPJ), and haemor- torial mouthparts seems to have been much more important for the rhoidalis (Germar, 1818) (Poland; cPJ) were studied by scanning radiation of Eucinetidae, which include five, out of the total number electron microscopy; morphological structures of all remaining of ten extant genera, with the prementum modified to a various extant Eucinetidae were extracted from descriptions and illustra- extent. In Bisaya and possibly also in one species of Proeuzkus, the tions given by Bullians & Leschen (2004), Nikitsky (1996), and Vít prementum is intermediary between the unmodified and the (1977, 1985, 1995, 2000). Acalyptomerus sp. was selected to root suctorial form, and these mouthparts can be regarded as semi- the analysis. suctorial, although their function is not known. It is also un- Phylogenetic analysis was based on 22 non-additive and unor- known whether the taxa with modified mouthparts form a dered adult morphological characters; inapplicable entries were monophyletic group within Eucinetidae, as phylogenetic re- assigned a gap value (“e”) and treated equivalent to missing data constructions for this family have not been obtained so far. Some (“?”). Character states coded as 0 do not indicate plesiomorphies. The compression fossils were attributed to Eucinetidae, or to a new data matrix was assembled in Nexus Data Editor for Windows v. 0.5.0 family yMesocinetidae Kirejtshuk & Ponomarenko, 2010, presum- (Page, 2001); characters are numbered starting from zero (as ably closely related to Eucinetidae; they come from the Lower required by TNT); parsimony analyses were conducted in TNT Cretaceous of China (136.4e130.0 Ma), and Upper Jurassic of (Goloboff et al., 2008) in two variants: under equal weights and with Mongolia (150.8e145.5 Ma), respectively (Hong, 1995; Kirejtshuk & implied weighting (at the weighting function K ranging from 3.0 to Ponomarenko, 2010). Actual relationships of these taxa within 9.0) using the implicit enumeration method. The symmetric resam- Scirtoidea need to be clarified, but none of these extinct beetles has pling (P ¼ 33; 100 replicates) was also conducted in TNT. Character modified, suctorial mouthparts. mapping was made in WinClada v. 1.00.08 (Nixon, 1999); trees were In the present study the first definite Upper Cretaceous member annotated in Corel 9.397. The characters and character states are of Eucinetidae is reported, and as its mouthparts represent the given in Appendix A; the data matrix is presented in Appendix B. suctorial form, an attempt to place the new taxon within the taxonomic context is also made. 4. Systematic palaeontology 2. Geographic and geological context Suborder: Emery, 1886 Superfamily: Scirtoidea Fleming, 1821 The studied specimen comes from the Hukawng Valley, Kachin Family: Eucinetidae Lacordaire, 1857 State of northern Myanmar. The only amber mine which is a subject of a commercial extraction is located in the Noije Bum Hill Genus yCretohlezkus Jałoszynski gen. nov. (26150N; 96340E) (e.g., Jałoszynski et al., 2017a, b: fig. 1), which urn:lsid:zoobank.org:act:D8D9421F-832C-4AC0-8B72- consists of folded Cretaceous and Paleogene deposits (Cruickshank 8B5C76126692 & Ko, 2003). Amber is associated with a narrow horizon in fine- Fig. 1 grained facies and it was dated as of the earliest Cenomanian age (98.79 ± 0.62 Ma) by Cruickshank & Ko (2003) and Shi et al. (2012). Derivation of name. The name is based on a stem derived from the Marine fossils such as ammonites and foraminifers, abundance of extant genus name Tohlezkus, combined with the prefix Cre-, which amber, coalified plant materials and common coal laminations in is short for Creto- and refers to the age of the fossil. Gender the fine clastic facies suggest that depositional environment must masculine. have been nearshore (Cruickshank & Ko, 2003). Type species. yCretohlezkus alleni Jałoszynski (here designated). Diagnosis. Prementum suctorial, strongly elongate and sub- 3. Material and methods triangular; frontoclypeal suture present; labial palps much longer than prementum; labial palpomere 1 extremely elongate, much 3.1. Specimen handling and imaging longer than 2. Description. Body (Fig. 1AeF) fusiform and slender, moderately The fossil specimen here described is deposited at MNHW, with convex dorsally and flattened ventrally, not constricted between the collection number 1331. The inclusion was observed (as dry pronotum and elytra. Vestiture of setae dense, short, suberect to specimen and submerged in cedar oil for better visibility) under erect. Head (Fig. 1C, E, F) strongly tilted ventrad so that entire frons Nikon SMZ1500 (Nikon, Tokyo, Japan) and Leica M205C (Leica and a part of vertex are visible in ventral view; surface of frons and Microsystems, Wetzlar, Germany) stereomicroscopes. Photographs vertex partly collapsed; posterior margin of vertex broadly were taken on white background using a KYF75U digital camera rounded; anterior margin of head shallowly and broadly emar- (JVC, Yokohama, Japan) mounted to the Leica microscope. Image ginate; labrum indistinguishably fused with clypeus, which is stacks were processed using Helicon Focus v. 6.8.0 (HeliconSoft demarcated from frons by a fine frontoclypeal groove (Fig. 1E; fcg); Ltd.) and edited with Corel PhotoPaint 9.397. Morphological composite eyes (Fig. 1E; ce) large, lateral; antennal insertions close structures were figured by freehand drawing, with exact pro- to anteromesal margin of each eye. Prementum, labial and maxil- portions and general shapes sketched from photographs, using lary palps exposed, remaining mouthparts not observable; pre- specimens observed at various angles. The work is registered in mentum (Fig. 1E; pre) strongly elongate, triangular, strongly ZooBank under urn:lsid:zoobank.org:pub:B1EEAFE0-FC2D-4A72- narrowed anterad; labial palp conspicuously long, longer than 8C1F-4BE4AEB84BA0. prementum, with all palpomeres strongly elongate, palpomere 1 (Fig. 1E; lp1) at least 5 as long as broad (its basal portion not 3.2. Phylogenetic analysis visible, presumably slightly longer), cylindrical; palpomere 2 (Fig. 1E; lp2) shorter than 1, about 3 as long as broad, cylindrical; The ingroup taxa include adult representatives of all extant palpomere 3 (Fig.1E; lp3) longest, fusiform with long apical rod-like genera of Eucinetidae and the newly described extinct genus; the projection, broadest slightly before middle; maxillary palp as long outgroup is Acalyptomerus sp. (Japan; cPJ), Scirtoidea: , as head, palpomere 1 not visible, but presumably minute, palpo- presumably the most basal member of the candidate sister group of mere 2 (Fig. 1E; mxp2) at least 4 as long as broad (its basal portion Eucinetidae (Leschen, 2016). Specimens of Acalyptomerus sp., not visible, presumably slightly longer), cylindrical; palpomere 3 128 P. Jałoszynski / Cretaceous Research 100 (2019) 126e133

Fig. 1. yCretohlezkus alleni gen. et sp. nov. Dorsal (A, D), ventral (B, F) habitus and close-up of head (C, E) of the holotype (MNHW1331). Abbreviations: ce, composite eye; fcs, frontoclypeal suture; lp1e3, labial palpomere 1e3; mtcxp, metacoxal plate; mxp2e4, maxillary palpomere 2e4; pd, pedicel; pre, prementum; sc, scape. Scale bars: A, B, D, F: 1 mm; C: 0.1 mm. P. Jałoszynski / Cretaceous Research 100 (2019) 126e133 129

(Fig. 1E; mxp3) longer than 2, about 5 as long as broad, indis- extremely elongate, almost as long as 4 (about half as long as 4 in tinctly broadened distad, palpomere 4 (Fig. 1; mxp4) longest, Bisaya); iv) the labial palpomere 2 much shorter than 3 (about as distinctly longer than 3, fusiform with slender apical portion, long as 3 in Bisaya); the labial palpomere 3 fusiform, broader than broadest near middle. 2 and with a rod-like apical projection (in Bisaya much narrower than 2, gradually and weakly narrowing from near base to apex); Prothorax (Fig.1A, D, F)) strongly transverse; pronotum in dorsal - from Eucilodes in: i) the head at antennal insertions not con- view (Fig. 1D) with anterior and lateral margins broadly rounded stricted (strongly constricted in Eucilodes); ii) the maxillary together; posterior pronotal corners acute; pronotal base strongly palpomere 3 extremely elongate, almost as long as 4 (very short, expanded caudad in front of scutellum. Ventral structures not about half as long as 4 in Eucilodes); iii) the labial palpomere 2 visible. much shorter than 3 (longer than 3 in Eucilodes); iv) the labial Elytra (Fig. 1A, D) strongly elongate, adsutural striae present, palpomere 3 fusiform, broader than 2 and with a rod-like apical incomplete, not reaching elytral base and apex, distinctly conver- projection (in Eucilodes much narrower than 2, gradually and gent posterad; humeral calli indistinct; apices separately rounded, weakly narrowing from near base to apex); side of each elytron in subapical region slightly sinuate. - from Jentozkus in: i) the head at antennal insertions not con- Mesoscutellar shield (Fig. 1D) exposed between elytral bases, stricted (strongly constricted in Jentozkus); ii) the antennae with subtriangular, elongate. Mesoventral structures not visible. proximal antennomeres strongly elongate and loosely assem- Metaventrite hidden under metacoxal plates. bled, and a subconical apex of the antennomere 11 (all flag- Hind wings (Fig. 1B, F) exposed, presumably functional. ellomeres transverse and compactly assembled in Jentozkus, and Abdomen (Fig. 1F) about as long as meso- and metaventrite apex of 11 truncate); iii) the maxillary palpomere 3 extremely combined, but number of abdominal sternites not possible to elongate, almost as long as 4 (very short, less than half as long as assess; the number of transverse rows of short and dense setae is 4inJentozkus); iv) the labial palpomere 2 much shorter than 3 larger than a number of sternites known in extant forms, pre- (longer than 3 in Jentozkus); v) the labial palpomere 3 fusiform, sumably some of the rows are on the posterior margins, and some broader than 2 and with a rod-like apical projection (in Jentoz- on the ventral surface of sternites. kus much narrower than 2, gradually and weakly narrowing Legs (Fig. 1F) moderately long, robust. Procoxa and protro- from near base to apex); chanter poorly visible; profemur flattened, slender, protibia slightly - from Proeuzkus in: i) the antennae with proximal antennomeres flattened, broadened distad, slightly shorter than profemur, proti- strongly elongate and loosely assembled, and a subconical apex bial apex lacking noticeable spines or spurs, protarsus slightly of the antennomere 11 (all flagellomeres transverse and longer than protibia, tarsomeres become gradually shorter distad, compactly assembled in Proeuzkus, and apex of 11 truncate); ii) except for tarsomere 5, which is about as long as three preceding the maxillary palpomere 3 extremely elongate, almost as long as tarsomeres, all protarsomeres lacking any visible spines. Mesocoxa 4 (very short, less than half as long as 4 in Proeuzkus); iii) the and mesotrochanter not visible, mesofemur strongly flattened, labial palpomere 2 much shorter than 3 (longer than 3 in broad, about 3 as long as broad, mesotibia slightly flattened, Proeuzkus); broadened distad, with two long spurs, of which one is longer and - from Tohlezkus in: i) the antennae with proximal antennomeres has an asymmetric apex (in Fig. 1F visible on the right middle leg) strongly elongate and loosely assembled, and a subconical apex and a row of apical spines, mesotarsus distinctly longer than of antennomere 11 (all flagellomeres transverse and compactly mesotibia, tarsomeres 1e4 become gradually shorter and each with assembled in Tohlezkus, and apex of 11 truncate); ii) the maxil- apical row of several spines, tarsomere 5 slightly longer than 4. lary palpomere 3 extremely elongate, almost as long as 4 (very Metacoxae, metatrochanters, metafemora and bases of metatibiae short, less than half as long as 4 in Tohlezkus); iii) the labial hidden under metacoxal plates (Fig. 1F; mtcxp) which touch at palpomere 2 much shorter than 3 (longer than 3 in Tohlezkus). middle on nearly entire length and have their lateral margins nearly Species yCretohlezkus alleni Jałoszynski sp. nov. straight and posterior margins rounded; metatibia broadened dis- tad, with one long apical spur visible and a row of apical spines, urn:lsid:zoobank.org:act:75FEF852-26D6-43AE-8471- metatarsus presumably longer than metatibia, tarsomeres 1e4 9ECCA12DAD4E become gradually shorter and each with apical row of several Fig. 1 spines, tarsomere 5 almost as long as 3e4. Material studied. Holotype (catalogue number MNHW1331), from Burmese amber, sex unknown; inclusion in a clear amber Remarks. yCretohlezkus differs from Eucinetus, Euscaphurus, Euci- prism ~ 8 5 1.5 mm (MNHW). netella, Noteucinetus and Nycteus in the modified prementum, Derivation of name. Patronymic dedicated to Albert Allen, Star, which forms a piercing apparatus. This character is shared with Idaho, USA, who kindly donated this, and several other interesting Bisaya, Eucilodes, Jentozkus, Proeuzkus and Tohlezkus, although in specimens for my study. Bisaya and one species of Proeuzkus the prementum is only slightly Type locality and horizon. Hukawng Valley, Kachin State, northern elongate and not triangular, but subtrapezoidal. The presence of Myanmar; lowermost Cenomanian, Upper Cretaceous. frontoclypeal suture; the labial palpomere 1 extremely elongate, Diagnosis. As for genus (vide supra). much longer than 2; and the labial palps longer than the pre- Description. Body (Fig. 1AeF) fusiform and relatively slender, length mentum in yCretohlezkus clearly differentiate this genus from all 1.63 mm (measured in dorsal view, excluding head), pigmentation remaining genera of the ‘suctorial group’. Additionally, dark brown, body covered with dense, short and suberect to erect yCretohlezkus differs from each member of this group in the setae that appear slightly lighter than cuticle. Head (Fig. 1C, E) following characters: slightly transverse, length 0.23 mm, width 0.30 mm; vertex and - from Bisaya in: i) the antennae with six terminal antennomeres frons partly collapsed; frontoclypeal suture (Fig. 1E; fcs) fine but distinctly thickened, and the apex of 11 subconical (in Bisaya 4 well-visible; anterior margin of head distinctly emarginate. Punc- terminal antennomeres thickened and apex of 11 truncate); ii) tures on frons and vertex indiscernible, setae short, sparse and the prementum subtriangular, nearly 3 as long as broad (in suberect. Antenna (Fig. 1F) moderately long, slender, length Bisaya prementum subtrapezoidal with truncate apex, only 0.50 mm, distinctly thickened in distal half, scape and pedicel about twice as long as broad); iii) the maxillary palpomere 3 130 P. Jałoszynski / Cretaceous Research 100 (2019) 126e133

(Fig. 1E; sc, ped) each distinctly elongate, antennomeres 3e5 each monophyly of Eucinetidae excluding Eucinetella is supported by strongly elongate, about 3 as long as broad, antennomere 6 two unique apomorphies: the pedicel subcylindrical (character slightly elongate, 7 about as long as broad, 8e10 each indistinctly 14(1); in Eucinetella and Acalyptomerus subglobose), and pedicel transverse, 11 slightly longer than broad, with subtriangular, elongate (15(2)); in Eucinetella and Acalyptomerus about as long as slightly asymmetrical apex. All flagellomeres densely but finely broad, but this character state is reversed in Tohlezkus, which also setose. has a short pedicel). The monophyly of all taxa with the modified mouthparts is supported by two unique apomorphies: the anterior Pronotum (Fig. 1A, D) strongly transverse, length 0.30 mm, margin of head concave (3(1), but reversed in Proeuzkus), and the width 0.53 mm; broadest at base. Sides and anterior margin elongate prementum (6(1); but reversed in one unusual species of confluent, rounded, posterior pronotal corners sharp-angled; pos- Proeuzkus). terior margin bisinuate, strongly projecting posterad at middle. Elytra (1A, D) slender, oval, length 1.33 mm, width 0.75 mm; 6. Discussion apical region with slightly concave sides, apices separately rounded; adsutural striae distinct. Elytral punctures barely The only example of a complex mouthpart modification in discernible, setae short and suberect, dense. beetles associated with unusual feeding habits, whose structure Legs short and robust, unmodified. (including soft tissues) and function in extant species is well- studied, and whose evolution was traced back to Cretaceous, is the strongly specialized labium of some ant-like stone beetles 5. Preliminary phylogeny of Eucinetidae and placement of (Staphylinidae: Scydmaeninae). Scydmaenines use suction discs on yCretohlezkus the prementum to immobilize armoured mites, which is a unique morphological and behavioural adaptation among beetles. The The analysis under equal weights resulted in 6 equally most exoskeleton and musculature of labial suckers as well as their parsimonious trees (MPTs), tree length (L) ¼ 46, consistency index presumable functional mechanism were studied in extant (CI) ¼ 0.52, retention index (RI) ¼ 0.62. The strict consensus tree cephenniine scydmaenines (Jałoszynski & Beutel, 2012); the role was largely unresolved. Re-analysis under implied weights resulted during prey capture and the prey preferences were studied in in 1 (at K ¼ 3, 5e9) or 2 (at K ¼ 4) MPTs representing two alter- extant cephenniine and glandulariine scydmaenines (Jałoszynski & native topologies; shown in Fig.2. The single MPT at K ¼ 3(L¼ 47, Olszanowski, 2016; Jałoszynski, 2016a); and a similarly modified CI ¼ 0.51, RI ¼ 0.61) and K ¼ 6(L¼ 46, CI ¼ 0.52, RI ¼ 0.62) are prementum was documented in a Turonian glandulariine species presented for further discussion. (Jałoszynski et al., 2017a, 2017b). Less complex morphological ad- The two trees differ only in the placement and arrangement of aptations of maxillae, mandibles or palps to a specialized feeding taxa with non-suctorial mouthparts, which, however, do not form a on fungal spores or fruiting bodies of fungi were demonstrated in monophyletic group. All the taxa with modified prementum (suc- extinct Proteininae (Cai et al., 2016) and Oxyporinae (Cai et al., torial or semi-suctorial), in turn, were recovered as a clade, with 2017) staphylinids. Adults of the leiodid, cerylonid and eucinetid Eucilodes branching off first, and yCretohlezkus placed as sister to all beetles showing a suctorial, possibly piercing or piercing-sucking remaining members of this monophylum. However, the branches feeding apparatus (unique among Coleoptera), have never been a are not supported by the symmetric resampling, except for a subject of detailed morphological and behavioural studies. The moderate support for the sister group relationship between the bizarre modifications of their mouthparts, until now, have not been Palaearctic Eucinetus haemorrhoidalis and Nycteus meridionalis. The discovered in the fossil record. yCretohlezkus is the first beetle

Fig. 2. Results of the preliminary parsimony analysis of the phylogenetic relationships of Eucinetidae focused on clarifying the placement of yCretohlezkus. Single MPT obtained under implied weights at the weighting function K ¼ 3 (A), and single MPT obtained under implied weighting at K ¼ 6 (B). Symmetric resampling support values are shown below branches (values < 50 are omitted). Unambiguously optimized character changes are plotted along the internodes. Black circles indicate unique character changes; white circles indicate parallelisms or reversals; character numbers are above circles; character states below circles. The ‘suctorial eucinetids’ are highlighted in frame. P. Jałoszynski / Cretaceous Research 100 (2019) 126e133 131 showing suctorial mouthparts recorded as a fossil, and its old seems plausible. Eucilodes, recovered as the most basal lineage of Cenomanian age clearly demonstrates that an entire branch of the ‘suctorial eucinetids’, has a large body, typical of non-suctorial Eucinetidae (the ‘suctorial eucinetids’) had differentiated even Eucinetus and Nycteus; and Eucilodes, yCretohlezkus and Bisaya (all earlier. Although the phylogenetic results presented here must be recovered as most basal lineages of the ‘suctorial eucinetids’)have regarded as preliminary (most branches unsupported; a more slender antennae, resembling those in most genera with non- detailed morphological analysis of extant genera is necessary to put suctorial mouthparts, and unlike those in the remaining taxa forward a robust phylogenetic hypothesis), the placement of with the modified labium. yCretohlezkus has the frontoclypeal su- yCretohlezkus lineage close to the base of the ‘suctorial eucinetids’ ture, a character that was previously known only in the

Fig. 3. Examples of extant ‘suctorial’ (AeC) and ‘non-suctorial’ (D) Eucinetidae. Dorsal (A) and ventral (B) habitus and head in anterior view (C) of Tohlezkus rufus; head in anterior view of Eucinetus haemorrhoidalis. Abbreviations: ce, composite eye; fcs, frontoclypeal suture; lbr, labrum; lp, labial palp; mtcxp, metacoxal plate; mxp, maxillary palp; pre, prementum. Scale bars: A, B: 0.5 mm; C: 0.1 mm; D: 0.2 mm. 132 P. Jałoszynski / Cretaceous Research 100 (2019) 126e133 unspecialized eucinetids with the unmodified labium. The strongly Nomura (National Museum of Nature and Science, Tsukuba, Japan) modified prementum of yCretohlezkus is as long as that in its extant and Adam Slipinski (CSIRO, Canberra, Australia) are thanked for relatives (cf. Fig. 3AeC), demonstrating that an advanced stage of their help in obtaining copies of some papers on Eucinetidae. Ming morphological feeding specialization in this lineage has developed Bai and Yuanyuan Lu (Inst. Zool., Chinese Ac. Sci.) kindly translated during or likely before Upper Cretaceous. The lineages of ‘non- the Chinese description of yHuaxiacinectus. Two anonymous re- suctorial’ eucinetids (an example shown in Fig. 3D) have branched viewers are thanked for their valuable comments and corrections. off earlier, and the extant Early Cretaceous yMesocinetidae and Late Jurassic yHuaxiacinectus Hong, 1995, all with unmodified mouth- parts, might have been their close relatives. References In order to understand the evolution of the suctorial mouthparts in eucinetids, it is necessary to carry out detailed functional- Bullians, M.S., Leschen, R.A.B., 2004. Noteucinetus new genus from New Zealand and morphological studies of extant species, to identify their sources Chile and notes on Eucinetus stewarti (Broun) (Coleoptera: Eucinetidae). New Zealand Entomologist 27, 29e38. of food, and to make behavioural observations. Surprisingly, after Cai, C., Newton, A.F., Thayer, M.K., Leschen, R.A.B., Huang, D., 2016. Specialized over 160 years of recognizing eucinetids as a distinct group within proteinine rove beetles shed light on - fungal associations in the Creta- beetles, we do not know anything about their feeding habits with ceous. Proceedings of the Royal Society B: Biological Sciences 283, 20161439. Cai, C., Leschen, R.A.B., Hibbett, D.S., Xia, F., Huang, D., 2017. Mycophagous rove any certainty - what exactly these beetles need the long pre- beetles highlight diverse mushrooms in the Cretaceous. Nature Communica- mentum for, how it functions within the entire feeding apparatus, tions 8, 14894. how the food is transferred into the mouth opening, and what Casey, T.L., 1885. New genera and species of Californian Coleoptera. Bulletin of the California Academy of Sciences 1, 283e336. exactly the beetles feed on - all these questions remain unan- Cruickshank, R.D., Ko, K., 2003. Geology of an amber locality in the Hukawng Valley, swered. The suggestion that eucinetids feed on Myxomycetes or northern Myanmar. Journal of Asian Earth Sciences 21, 441e455. Basidiomycetes (e.g., Leschen, 2016) is based on finding adults of Emery, C., 1886. Über Phylogenie und Systematik der Insekten. Biologisches Zen- tralblatt 5, 648e656. extant species in association with these organisms, not on direct Fleming, J., 1821. Insecta. Supplement to the Fourth, Fifth and Sixth Editions of the observations of their feeding. yCretohlezkus is yet another example Encyclopaedia Britannica Volume Fifth [Part 1]. A. Constable and Company, of a beetle showing an unusual morphological adaptation, whose Edinburgh, pp. 41e56 pl. 85. € exact role during feeding remains a subject of speculations, despite Germar, E.F., 1818. VIII Vermischte Bemerkungen über einige Kaferarten. Magazin der Entomologie 3, 228e260. its long evolutionary history. The same problem was encountered Goloboff, P., Farris, J., Nixon, K., 2008. TNT, a free program for phylogenetic analysis. in other beetle families. For instance, bizarre modifications of the Cladistics 24, 774e786. fi Hong, Y.C., 1995. Fossil of the southern Ordos Basin. Acta Geologica Gansu 4 postocular region of the head, modi ed bristles on the maxillary e fi (1), 1 13 in Chinese with English summary). palps, or extremely long spines on the modi ed scape and pedicel Jałoszynski, P., 2012. Description of Euroleptochromus gen.n. (Coleoptera, Staph- in some mastigite ant-like stone beetles have been known in extant ylinidae, Scydmaeninae) from Baltic amber, with discussion of biogeography taxa for over a century, and recently were documented in Creta- and mouthpart evolution within Clidicini. Systematic Entomology 37, 346e359. ł ł Ja oszynski, P., 2016a. Mature larva of Stenichnus godarti (Latreille) (Coleoptera: ceous and Paleogene ambers (e.g., Ja oszynski, 2012, 2016b; Staphylinidae, Scydmaeninae): redescription, hypothesis of displaced epicranial Jaloszynski et al., 2017a, 2017b, 2018; Yin et al., 2018). Yet we still suture and alternative interpretation of homology between chaetotaxic struc- do not know the function of these enigmatic modifications. They tures. Zootaxa 4196 (1), 77e94. Jałoszynski, P., 2016b. A new Eocene genus of ant-like stone beetles sheds new light demonstrate how incomplete morphological, functional and on the evolution of Mastigini. Journal of Paleontology 89 (6), 1056e1067. behavioural studies of extant insects are, and until so many ques- Jałoszynski, P., Beutel, R., 2012. Functional morphology and evolution of specialized tions remain unanswered, the important palaeontological findings mouthparts of Cephenniini (Scydmaeninae, Staphylinidae). Structure y & Development 41, 593e607. as that of Cretohlezkus lack the functional-morphological context. Jałoszynski, P., Brunke, A.J., Metscher, B., Zhang, W.-W., Bai, M., 2017a. Clidicostigus gen. nov., the first Mesozoic genus of Mastigini (Coleoptera: Staphylinidae: 7. Conclusions Scydmaeninae) from Cenomanian Burmese amber. Cretaceous Research 72, 110e116. Jałoszynski, P., Brunke, A.J., Yamamoto, S., Takahashi, Y., 2018. Evolution of Masti- For the first time, a Cretaceous member of the extant family gitae: Mesozoic and Cenozoic fossils crucial for reclassification of extant tribes Eucinetidae showing highly modified, suctorial mouthparts is re- (Coleoptera: Staphylinidae: Scydmaeninae). Zoological Journal of the Linnean y Society 184 (3), 623e652. ported. A preliminary phylogenetic analysis placed Cretohlezkus ł ‘ Ja oszynski, P., Olszanowski, Z., 2016. Feeding of two species of Scydmaeninae 'hole among the basal branches of the monophyletic suctorial eucine- scrapers', Cephennium majus and C. ruthenum (Coleoptera: Staphylinidae), on tids’, a clade of taxa with the prementum transformed presumably oribatid mites. European Journal of Entomology 113, 372e386. for feeding on liquid food sources. The exact function and details of Jałoszynski, P., Perrichot, V., Peris, D., 2017b. Ninety million years of chasing mites e y by ant-like stone beetles. Gondwana Research 48, 1 6. feeding remain unknown even in extant relatives of Cretohlezkus, Kirejtshuk, A.G., Ponomarenkok, A.G., 2010. A new coleopterous family Meso- making it impossible to discuss its morphologically specialized cinetidae fam. nov. (Coleoptera: Scirtoidea) from Late Mesozoic and notes on feeding adaptation on a broader functional-morphological or fossil remains from Shar-Teg (Upper Jurassic, South-Western Mongolia). Zoo- systematica Rossica 19, 301e325. behavioural background. The Cenomanian age of the fossil, how- Lacordaire, J.T., 1857. Histoire naturelle des insectes. Genera des Coleopteres ou ever, demonstrates that this unusual type of mouthpart modifica- exposem ethodique et critique de tous les genres proposes jusqu’ici dans cet tion differentiated in the ancestor of the extant ‘suctorial ordre d’insectes. Tome quatrieme contenant les familles des buprestides, ’ throscides, eucnemides, elaterides, cebrionides, cerophytides, rhipicerides, eucinetids during or likely before Upper Cretaceous, which was dascyllides, malacodermes, clerides, lymexylones, cupesides, ptiniores, bos- presumably a key to the later radiation of this enigmatic group. trichides et cissides. Librairie Encyclopedique de Roret, Paris, 579 pp. Latreille, P.A., 1829. Crustaces, Arachnides et partie des Insectes. In: Cuvier, G. (Ed.), Acknowledgments Le Regne , distribue d'apres son organisation, pour servir de base a l'histoire naturelle des animaux et d'introduction a l'anatomie comparee. Nouvelle edition, revue et augmentee. Tome IV. Deterville & Crochard, Paris I thank Albert Allen, Star, Idaho, USA, who kindly donated an iexxvii, pp. 1e584. interesting amber inclusion. Marta Konikiewicz (Wrocław Univer- Lea, A.M., 1910. Australian and Tasmanian Coleoptera inhabiting or resorting to the ł nests of ants, bees and termites. Proceedings of the Royal Society of Victoria sity of Environmental and Life Sciences, Wroc aw, Poland) is (N.S.) 23 (1), 116e230. acknowledged for cutting and polishing the amber piece. I am also Leschen, R.A.B., 2016. 10.2. Eucinetidae Lacordaire, 1857. In: Beutel, R.G., indebted to Hiroyuki Yoshitomi (Ehime University Museum, Mat- Leschen, R.A.B. (Eds.), Handbook of Zoology, Vol. IV Arthropoda: Insecta. Cole- optera, Vol. 1: Morphology and Systematics (, , Myx- suyama, Japan) for hosting me during my stay in Matsuyama and ophaga, Polyphaga partim), second ed. Walter De Gruyter, Berlin/Boston, organizing a fieldtrip on which I collected Tohlezkus; Shûhei pp. 206e210. P. Jałoszynski / Cretaceous Research 100 (2019) 126e133 133

Newton, A.F., 2016. 14.4 Leiodidae Fleming, 1821. In: Beutel, R.G., Leschen, R.A.B. 5. Mentum: (0) strongly transverse; (1) about as long as broad. (Eds.), Handbook of Zoology, Vol. IV Arthropoda: Insecta. Coleoptera, Vol. 1: 6. Prementum: (0) short, broader than long and broadening anterad; (1) Morphology and Systematics (Archostemata, Adephaga, , Polyphaga elongate and at least slightly narrowing anterad. partim), second ed. Walter De Gruyter, Berlin/Boston, pp. 364e376. 7. Long prementum: (0) suctorial, strongly elongate and strongly narrowing Nikitsky, N.B., 1996. New Coleoptera from China. Zoologicheskii Zhurnal 75, distad; (1) semisuctorial, indistinctly elongate and only slightly narrowed 1366e1373 (in Russian with English summary). distad. Nixon, K.C., 1999e2002. WINCLADA (Beta), 1.00.08. Software published by the 8. Maxillary palp: (0) tetramerous; (1) trimerous. author, Ithaca, New York [WWW document]. http://www.cladistics.com. http:// 9. Maxillary palpomere III of tetramerous palp: (0) subequal to I and III; (1) much www.diversityoflife.org/winclada/. currently available at: shorter than I and III. Page, R.D.M., 2001. NDE: NEXUS Data Editor 0.5.0. University of Glasgow, Glasgow, 10. Maxillary palpomere IV: (0) with subconical apex; (1) with terminal ‘spine’ Scotland, UK [WWW document]. http://taxonomy.zoology.gla.ac.uk/rod/NDE/ (i.e., abruptly narrowed to form a slender rod-like apical projection). nde.html. 11. Labial palpomere III: (0) at base as broad as II; (1) rod-like, at base much Reitter, E., 1884. Diagnosen neuer Coleopteren aus Lenkoran. Verhandlungen des narrower than II. Naturforschenden Vereins in Brün 22, 3e10. 12. Antenna: (0) slender, with at least antennomere III elongate, loosely Sakai, M., 1980. A new genus of Eucinetidae from Japan (Coleoptera). Transactions of assembled; (1) stout, with most antennomeres strongly transverse and the Shikoku Entomological Society 15 (1e2), 83e85. compactly assembled. Sharp, D., 1885. On the Colydiidae collected by Mr. G. L. Lewis in Japan. Journal of 13. Slender antenna: (0) with distinct club or gradually thickened distad; (1) the Linnean Society of London: Zoology 19, 58e84. filiform. Shi, G., Grimaldi, D.A., Harlow, G.E., Wang, J., Wang, J., Yang, M., Lei, W., Li, Q., Li, X., 14. Shape of pedicel: (0) subglobose; (1) subcylindrical. 2012. Age constraint on Burmese amber based on U-Pb dating of zircons. 15. Length of pedicel: (0) about as long as broad; (1) transverse; (2) elongate. Cretaceous Research 37, 155e163. 16. Terminal antennomere: (0) about as broad as X; (1) conspicuously narrower Slipinski, S.A., 1991. A monograph of the world Cerylonidae (Coleoptera; Cucujoi- than X. dea). Part I - Introduction and higher classification. Annali del Museo Civico di 17. Apical margin of terminal antennomere: (0) rounded or subconical and blunt; Storia Naturale, pp. 1e273. "Giacomo Doria" LXXXVIII. (1) truncate. Vít, S., 1977. Contribution a la connaissance de la famille Eucinetidae (Coleoptera). 18. Mesoscutellum: (0) exposed; (1) not visible in intact beetles. Revue Suisse de Zoologie 84 (4), 917e935. 19. Metacoxal plates: (0) medially largely separated; (1) medially touching on Vít, S., 1985. Etude de la morphologie des especes palearctiques du genre Eucinetus more than half of their length. Germar et quelques remarques sur son utilisation taxonomique (Coleoptera 20. Length of metacoxal plates: (0) together broader than long; (1) together Eucinetidae). Annales de la Societ e suisse de Zoologie et du Museum d'Histoire about as long as broad. Naturelle de Geneve 92 (2), 421e460. 21. Anterior margins of metacoxal plates: (0) extending anterolaterad; (1) curved Vít, S., 1995. Deux especes nouvelles d'Eucinetidae d'Amerique du Nord partic- posterolaterad; (2) transverse in relation to long body axis. ulierement interessantes (Coleoptera: Eucinetidae). Elytron 9, 125e137. Vít, S., 2000. Contribution a la connaissance de la famille Eucinetidae (Coleoptera). Revue Suisse de Zoologie 107, 123e138. Yin, Z., Cai, C., Huang, D.-Y., 2018. A potentially diverse fauna of springtail-hunting Appendix B. Morphological data matrix for phylogenetic analysis of scydmaenines during the late Mesozoic (Coleoptera, Staphylinidae, Scydmae- ninae). Cretaceous Research 90, 163e167. Eucinetidae (‘–’ indicates inapplicable characters; ‘?’ indicates missing data). 0 0000000001 1111111112 2 Appendix A. Supplementary data 0 1234567890 1234567890 1 Acalyptomerus sp. 1 010110–1–– 0000000000 2 1 0101011011 1001201110 1 Supplementary data to this article can be found online at https://doi.org/10. Bisaya nossidiformis Cretohlezkus alleni 1 0110?10001 0001200010 ? 1016/j.cretres.2019.03.016. Eucilodes caucasicus 0 0011?10011 ?001200000 1 Eucinetella kurbatovi 1 0100?0–011 ?1?0001?00 1 Appendix A. Character states used in a preliminary Eucinetus haemorrhoidalis 0 010010–000 0011200000 1 Euscaphurus saltator 1 010000–011 ?001200001 0 phylogenetic analysis of Eucinetidae. Jentozkus plaumanni 1 0011?10011 11–1211111 0 Noteucinetus nunni 1 010000–010 0011200000 0 0. Body size: (0) large (2.4e4 mm); (1) minute (1.5e2.1 mm). Nycteus hopfgarteni 0 010010–011 0011200000 1 1. Anterior portion of head capsule: (0) subtrapezoidal or rounded; (1) Nycteus meridionalis 0 010010–000 0011200000 1 1 1101?10011 11–1111000 0 subtriangular. Proeuzkus coecus 1 1100101011 11–1101000 0 2. Frontoclypeal region: (0) strongly constricted between antennal insertions; Proeuzkus pachys 1 1111010011 11–1001101 0 (1) not constricted. Tohlezkus rufus 3. Anterior margin of frontoclypeal region: (0) straight or rounded; (1) concave. 4. Frontoclypeal suture: (0) present; (1) absent.