The description of Prototrichalus gen. nov. 
and three new species from Burmese amber 
supports a mid-Cretaceous origin of the 
Metriorrhynchini (Coleoptera, Lycidae)
Authors: Francisco Molino-Olmedo, Vinicius S. 
Ferreira, Marc A. Branham, & Michael A. Ivie Michael 
© 2020 This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://
creativecommons.org/licenses/by-nc-nd/4.0/
Molino-Olmedo, Francisco, Vinicius S. Ferreira, Marc A. Branham, and Michael A. Ivie. “The 
Description of Prototrichalus Gen. Nov. and Three New Species from Burmese Amber Supports a 
Mid-Cretaceous Origin of the Metriorrhynchini (Coleoptera, Lycidae).” Cretaceous Research 111 
(July 2020): 104452. doi:10.1016/j.cretres.2020.104452. 
Made available through Montana State University’s ScholarWorks 
scholarworks.montana.edu 
The description of Prototrichalus gen. nov. and three new species from Burmese Amber 
supports a mid-Cretaceous origin of the Metriorrhynchini (Coleoptera, Lycidae) 
FRANCISCO MOLINO-OLMEDO¹, VINICIUS S. FERREIRA²*, MARC A. BRANHAM3 and 
MICHAEL A. IVIE² 
¹c/ La Zambra, 8- 23100 Mancha Real (Jaén), Spain. f.molino@yahoo.es 
² Montana Entomology Collection, Marsh Labs, Room 50, Montana State University, 1911 W. 
Lincoln Street, Bozeman, MT 59717, USA. vinicius.sfb@gmail.com; mivie@montana.edu 
3 Department of Entomology and Nematology, University of Florida, 1881 Natural Area Dr, 
Gainesville, FL 32608, USA. marcbran@ufl.edu  
*corresponding author
Abstract 
Despite the many substantial advances and progress in understanding the internal evolutionary 
relations of several Lycidae groups, the divergence time estimation of the family within 
Elateroidea remains subject of debate, with estimates to as early as the early to mid-Jurassic. 
Herein we describe Prototrichalus gen. nov., and three new species: Prototrichalus sepronai sp. 
nov., Prototrichalus meiyingae sp. nov.and Prototrichalus milleri sp. nov., from Burmese amber 
of the Cenomanian Age (mid-Cretaceous), supporting an age for the tribe of  at least 100 Ma. 
The new taxa belong to the tribe Metriorrhynchini and are the oldest recognizable beetles from 
this lineage, indeed, among the oldest known representatives of the Lycidae. The discovery and 
description of Prototrichalus and its three species provides direct evidence of the group’s as a 
recognizable group in the mid-Cretaceous, much earlier than the recent predictions in the Late 
Cretaceous. 
1. Introduction
With up to 4,600 extant species (Bocak and Bocakova 2008, 2010; Masek et al. 2018) 
and 12 fossil taxa described, including Dominican, Baltic and Burmese ambers (Ferreira and Ivie 
2017; Bocak et al. 2019; Tihelka et al. 2019; Kazantsev 2019, and citations therein), the family 
Lycidae has representatives in both temperate and tropical regions with a nearly worldwide 
distribution (Bocak and Bocakova 2010’ Ferreira and Ivie 2017; Masek et al. 2018,). In the 
species where males of both sexes attain a fully adult morphology, lycids can be recognized 
among other elateroids by the 7 (female) or 8 (male) ventrites and the conical, separated 
mesocoxae. In the vast majority of species, the pronotum is divided into 2 or more cells (areolae) 
by raised ridges, and the elytra with the presence of longitudinal costae on each, often reticulate 
elytron. Larvae and extreme pedomorphic females (lacking compound eyes, bifid tarsal claws, a 
multi-piece antennal flagellum and elytra) can be distinguished by the non-opposable, mandibles 
that are each divided longitudinally. 
The family Lycidae is one of the better studied families of beetles in the superfamily 
Elateroidea.  In the past decade several phylogenies (e.g. Kazantsev 2005; Bocak and Bocakova 
2008; Bocak et al. 2008; Masek et al. 2018, Kusy et al. 2019), new descriptions of extinct and 
extant taxa and taxonomic revisions have appeared (e.g. Ferreira 2015; Kazantsev 2017; Ferreira 
and Ivie 2017; Ferreira and Ivie 2018a, 2018b; Li et al. 2018). However, despite the many 
advances and substantial progress in understanding the internal evolutionary relationships of 
several lycid groups (e.g. Masek et al. 2014; Sklenarova et al. 2014;  Motyka et al. 2017), the 
divergence time estimation of Lycidae within Elateroidea (as well as many other beetle families) 
remains subject to debate.  
Hunt et al. (2007) estimated the origin of Elateroidea, including Lycidae at over 140 Ma 
(early Cretaceous). McKenna et al. (2015) proposed a minimum estimation origin of Lycidae of 
about 50 Ma (early Cenozoic). Toussaint et al. (2016) and Zhang et al. (2018), added more 
calibration points to their phylogenies and proposed minimum estimation dates of 95 Ma and 120 
Ma (both mid-Cretaceous), respectively, for the origin of Lycidae as a whole. As predicted by 
Toussaint et al. (2016) and Zhang et al. (2018), two mid-Cretaceous lycid fossils from two 
different lineages were discovered and described by Bocak et al. (2019) and Tihelka et al. (2019) 
which provided evidence for an earlier diversification of Lycidae, pushing the origins of the 
family to a minimum of 100 Ma in the Cretaceous. In the most recent and exhaustive study to 
date, McKenna et al. (2019) push the origin of Lycidae into the Jurassic, with standard deviation 
going as early as the late Triassic. 
Herein we report a new lycid genus with three new species from Cretaceous-age burmite 
belonging to the tribe Metriorrhynchini, the first fossil records for the tribe. The tribe is among 
the most diverse in number of genera and species in the family (Bocak 2002; Sklenarova et al. 
2014). With an extraordinary diversity in Southeast Asia, Wallacea and New Guinea (Kazantsev 
2012a; Sklenarova et al. 2014), it is also present in the Afrotropical and Australian regions (loc. 
cit.). Together with Burmolycus compactus Bocak, Li and Ellenberger, 2019 and Cretolycus 
praecursor Tihelka, Huang and Cai, 2019, our new genus and three species add to this the oldest 
assemblage of Lycidae. 
2. Material and Methods
The specimens (total number = 5) were obtained by FMO (2 specimens) and by Dr. 
Meiying Lin (Institute of Zoology, Chinese Academy of Sciences, Beijing, P.R. China) (3 
specimens), and Dr. Lin later donated the material to MAB. All specimens are amber inclusions. 
The specimens obtained by FMO and Dr. Lin are from Noije Bum Village, Hukawng Valley, 
Northern Myanmar (Kania et al., 2015: fig. 1A). Material from Hukawng Valley is comprised of 
folded sedimentary (±volcanic) rocks of Cretaceous and Cenozoic age, with a variety of clastic 
sedimentary rocks, with thin limestone beds and abundant carbonaceous material (Cruickshank 
and Ko 2003). Amber from this locality is dated to the earliest Cenomanian age in the mid-
Cretaceous, with an estimated age of 98.79 ± 0.62 Ma (Shi et al. 2012). Specimens are deposited 
in the National Museum of Natural History, Washington D.C., USA (USNM) and Montana 
Entomology Collection, Bozeman, MT, USA (MTEC). 
Specimens were studied under a Leica® Wild M3C and a KYOWA SM stereoscopic 
microscope with magnification up to 40x. Specimens were photographed submerged in olive oil 
and taken with either an OPTIKAM PRO HDMI – 4083.13, 6 megapixels camera, using 
OptikaISview software, attached to a KYOWA SM microscope or a Canon T3i DSLR with an 
MP-E 65 mm lens and a Stackshot ™ automated macro rail for focus stacking. Images were 
processed with Zerene Stacker® software version 1.04. Enhancements to digital images were 
made in Adobe Photoshop® CC 2019 and final plates prepared using Adobe Illustrator® CC 
2019. The distribution map technique follows Ferreira (2016). Morphological terminology 
follows Bocak and Bocakova (1990), Kazantsev (2005) and Lawrence et al. (2011). The 
taxonomic acts proposed in this work have been registered in ZooBank (see below), together 
with the electronic publication LSIC: urn:lsid:zoobank.org:pub:0250D333-39FF-4D34-8DDD-
CDA1D25B0661. 
3. Systematic Paleontology
Order Coleoptera Linnaeus, 1758 
Family Lycidae Laporte, 1836 
Subfamily Metriorrhynchinae Kleine, 1926 
Tribe Metriorrhynchini Kleine, 1926 
Genus Prototrichalus Molino-Olmedo, Ferreira, Branham and Ivie gen. nov. 
(urn:lsid:zoobank.org:act:278B85DB-F0C2-4C78-9F11-173815C1D956) 
Figs. 1 –3. 
Type species. Prototrichalus sepronai Olmedo, Ferreira, Branham and Ivie gen. et sp. 
nov. 
Etymology. The genus name is a combination of the name Trichalus Waterhouse, 1877, 
in reference to the new taxon’s resemblance with trichaline beetles, and the Ancient Greek 
combining form πρωτο-(proto-) of the word πρῶτος (protos), meaning first, in reference to the 
possibility of this genus being the ancestor of some of the lineages of trichaline beetles.  Gender 
masculine. 
Diagnosis. Prototrichalus, have an unique combination of features not present in any 
other Metriorrhynchini group: pronotum imarginate, rectangular or subtrapezoidal, bearing five 
large cells (Figs. 1A–1D, 2A, 2B, 3A, 3B); the presence of a carina on the mesoventrite 
separating the mesocoxae; elongate maxillary palp, with terminal palpomere of males 
securiforme (Figs. 1A–1B, 1F) and of females elongate (Figs. 2D, 3C–3D)); and the absence of 
secondary elytral costae (Figs. 1A, 1C, 2A, 3A).  
Species Included. Prototrichalus sepronai sp. nov., Prototrichalus meiyingae sp. nov. 
and Prototrichalus milleri sp. nov. 
Description. Pronotum with a fine pubescence, elytra glabrous (Figs. 1A–1D, 2A, 2B, 
3A, 3B), remainder of body with fine pubescence throughout (Figs. 2C, 3C). Body. Head: 
transverse, posteriorly partially covered by pronotum, apparently hypognathous (Figs. 1A–1C2, 
2C, 3C–3D). Eyes hemispherical, slightly projecting anterolaterally when viewed dorsally (Figs. 
3C-3D); coarsely granulate (Figs. 3C–3D).  Mouthparts: Maxillary palp four-segmented, 
elongate, with last palpomere acuminate (Figs. 2D, 3C–3D) or securiforme (Figs. 1A–1B, 1F). 
Mandibles short, connate with labrum, hooked apically (Fig. 3D). Clypeus and labrum transverse 
(Fig. 3D), posterior margin of labrum emarginate (Fig. 3D). Antennae: 11-segmented, ranging 
from pectinate (Fig. 1E–1F) to subserrate (Figs. 2A, 2C) or filiform (Figs. 3C–3D) reaching 
middle of elytra (Fig. 1E, 3C) or apical third (Fig. 2A); scape subconic, pedicel short. 
Prothorax: Pronotum transverse, rectangular (Figs. 2A, 2E) or trapezoidal (Figs. 1A–
1B), emarginate (Figs. 1A–1B, 2A, 2E), narrower than humeral width, angles roundish (Figs. 
1A–1B, 2A, 2E); disc region bearing 5 large cells (Figs. 1A-1B, 2E); median central areola 
reaching anterior and posterior margins of pronotum, enlarged in the center and slightly tapered 
towards margins (Figs. 1A–1B, 2E); posterior areolae one third shorter than anterior (Figs. 1A–
1B, 2E). Hypomeron concave. Mesothorax: Mesoventrite bearing a carina (Fig. 2E). Scutellum 
protruded, longer than wide, posteriorly bifurcated (Fig. 3A). Metathorax: Metaventrite convex, 
posterolateral angles pronounced, round; metadiscrimen complete (Figs. 2C, 3C). Elytra: 
irregularly punctate (Figs. 1A, 1C, 2A, 3A); subparallel, ranging from 3 to 4x longer than 
pronotum; with four primary elytral costae present; costa I short, only reaching basal third of 
elytra; costae II and III fused before apex (Fig. 3B) or free, not reaching apex (Figs. 1D, 2B); 
costa IV ranging from reaching third fourth of elytral length to first or second fourth of elytral 
length; secondary costae absent (Figs. 1D, 2B, 3B).  
Legs: elongate; femora and tibiae ranging from clavate to subparallel (Fig. 1C, 2C, 3C); 
apex of tibiae bearing a pair of spines; mesocoxae separated; metacoxae transverse (Fig. 3C); 
tarsomeres 5-5-5, tarsomeres II–IV expanded, with pads strongly developed, the V bearing 
simple claws (Figs. 1C, 2B). 
Abdomen of males presumably with eight visible ventrites (not visible), females with 
seven visible ventrites  (Figs. 2C, 3C). Female genitalia, styli very slender, apically located; 
coxites broadening towards apex (Fig. 3E). 
Length (pronotum+elytra):  7.5–9.0 mm. Width (across humeri): 2.0–2.8 mm.    
Distribution. All known species are from Myanmar. 
Type horizon. Cenomanian (ca. 98.79 ± 0.62 Ma), mid-Cretaceous (Shi et al. 2012). 
 
Key to the species of Prototrichalus 
1. Elytral costae II and III fused before reaching the apex (Fig. 3B); antennae filiform (Figs. 3C–
3D)…………………………………………………………………...….Prototrichalus meiyingae 
1'. Elytral costae II and III free, not fused and not reaching the apex of elytra (Figs. 1D, 2B); 
antennae pectinate or subserrate (Figs. 1C, 2A)………………………………..………………....2 
 
2. Pronotum bearing 5 areolae (Figs. 1A–1B); antennae pectinate (Fig. 1C); terminal maxillary 
palpomere securiforme (Figs. 1A–1B, 1F)………………….……….....Prototrichalus sepronai  
2'. Pronotum bearing 7 areolae, five larger ones and two small ones located adjacent to the 
posterior lateral margins of central areole (Fig. 2E); antennae subserrate (Fig. 2A); terminal 
maxillary palpomere elongate, longer than wide (Fig. 2D)……………….. Prototrichalus milleri 
Prototrichalus sepronai Molino-Olmedo, Ferreira, Branham and Ivie sp. nov. 
(urn:lsid:zoobank.org:act:8AB12E76-6FD7-473C-8936-6D49FC4F1B82) 
Figures. 1 A, B, C, D, E, F. 
Material examined (2). Holotype 1 ♂: MTEC 057001 (USNM).  Paratype 1♂: MTEC 
057002 (MTEC). 
Etymology. The species is named in honor of the Servicio de Protección de la 
Naturaleza (SEPRONA) in Spain, the unit of the Spanish Guardia Civil in charge of the 
protection of nature and cultural assets. 
Diagnosis. Prototrichalus sepronai can be separated from other Prototrichalus by the 
combination of pectinate antennae (Figs. 1A–1C, 1F), the subtrapezoidal pronotum (Figs. 1A–
1B), the securiform terminal maxillary palpomere (Figs. 1A–1B, 1F) and by the elytral costa IV 
reaching the posterior half of the elytra (Fig. 1C). 
Description. Head: transverse, posteriorly partially covered by pronotum, apparently 
hypognathous (Figs. 1A–1C, 1F). Maxillary palp four-segmented, elongate, with last palpomere 
securiform (Figs. 1A–1C, 1F). Antennae: reaching middle of elytra; antennomere III 3x longer 
than pedicel; IV–IX pectinate (Figs. 1C, 1E–1F), antennomere XI elongate. Pronotum transverse, 
trapezoidal (Figs. 1A–1B), imarginate, narrower than humeral width, angles roundish (Figs. 1A–
1B); disc bearing 5 large areole (Figs. 1A–1B); median central areola reaching anterior and 
posterior margins of pronotum, enlarged in the center and slightly tapered towards margins (Figs. 
1A–1B); posterior areolae one third shorter than anterior (Figs. 1A–1B). Elytra: subparallel, 
ranging from 3x longer than pronotum; costa I short, only reaching basal third of elytra; costae II 
and III free, not reaching apex (Fig. 1D); costa IV ranging from reaching third fourth of elytral 
length (Fig. 1C) to half of elytral length. Legs: somewhat slender, elongate; femora and tibiae 
subparallel (Figs. 1C–1E). 
Length (pronotum+elytra):  7.5–8.5 mm. Width (across humeri): 2.8 mm.    
Prototrichalus milleri Molino-Olmedo, Ferreira, Branham and Ivie sp. nov. 
(urn:lsid:zoobank.org:act:602EFFB2-B9C1-48A9-AD9A-54A655DD0433) 
Figures. 2 A, B, C, D and E. 
Material examined (1). Holotype 1 ♀: MTEC 057003 (USNM). 
Etymology. This species is named in honor of the North American Lycidae systematist, 
Richard Stuart Miller. 
Diagnosis. Prototrichalus milleri is unique among Prototrichalus by the combination of 
subserrate antennae (Fig. 2A), the elongate maxillary palp that is as long as half the length of 
antenna, the last palpomere acuminate (Fig. 2D); the elytral costae II and III free not reaching the 
elytral apex (Fig. 2B), and by the rectangularly emarginate transverse pronotum bearing 7 
areolae (Fig. 2E, note the two small areolae laterally adjacent to the central areole). 
Description. Head: transverse, posteriorly partially covered by pronotum, anteriorly with 
a small explained projection, apparently hypognathous (Figs. 2A, 2C–2D). Maxillary palp 
elongate, as long as half the length of antennae, with last palpomere acuminate, subequal in 
length with III; the sum of the length of the last two palpomeres subequal in length with 
palpomere II (Fig. 2D). Antennae: reaching 3/4 of elytral length, subserrate. Pronotum 
transverse, rectangular, imarginate (Fig. 2A), narrower than humeral width, angles roundish (Fig. 
2A, 2E); disc region bearing 5 areole (Fig. 2E) and one extra small areole in each posterolateral 
margin of central areole (Fig. 2E); Elytra: subparallel, 4x longer than pronotum; costa I short, 
only reaching basal third of elytra; costae II and III or free, not reaching apex (Figs. 2A–2B); 
costa IV  reaching third fourth of elytral length. Female genitalia damaged (Fig. 2B). 
Length (pronotum+elytra): 9.06 mm. Width (across humeri): 2 mm.    
Prototrichalus meiyingae Molino-Olmedo, Ferreira, Branham and Ivie sp. nov. 
(urn:lsid:zoobank.org:act:29F5C27D-EE42-4F91-A98B-2DBD4C673C6E) 
Figures. 3 A, B, C, D, E. 
Material examined (1). Holotype 1 ♀: MTEC 057004 (USNM). 
Etymology. This species is named for Dr. Mei-Ying Lin (Institute of Zoology, Chinese 
Academy of Sciences) who donated three of the five known specimens of Protrotrichalus that 
were used in this study. 
Diagnosis. Prototrichalus meiyingae can be separated from other Prototrichalus by the 
combination of filiform antennae (Figs. 3C–3D), the subtrapezoidal pronotum, elongate 
maxillary palps that is half as long as the antenna, with last palpomere acuminate (Fig. 3D) and 
by the elytral costae II and III fused before reaching apex (Figs. 3A–3B). 
Description. Head: transverse, posteriorly partially covered by pronotum, apparently 
hypognathous (Figs. 3C–3D). Maxillary palp four-segmented, elongate, as long as half the length 
of antennae, with last palpomere acuminate (Figs. 3C–3D). Antennae: reaching middle of elytra, 
filiform; antennomere III 4x longer than pedicel. Pronotum transverse, trapezoidal, imarginate, 
narrower than humeral width, angles roundish; disc region bearing 5 large areole; median central 
areola reaching anterior and posterior margins of pronotum, enlarged in the center and slightly 
tapered towards margins; Elytra: subparallel, 3x longer than pronotum; costa I short, only 
reaching basal third of elytra; costae II and III fused before reaching apex (Figs. 3A–3B) ; costa 
IV reaching second half elytral length. Legs: somewhat slender, elongate; femora and tibiae 
subparallel (Fig. 3C). Female genitalia, styli very slender, apically located, coxites broadening 
towards apex (Fig. 3E). 
Length (pronotum+elytra): 8 mm. Width (across humeri): 2.2 mm.    
Discussion 
 Comparison with extant taxa and tribal assignment 
Prototrichalus possesses all the characteristics that define a member of the family 
Lycidae (see introduction). The new genus has unique characters present only in the 
Metriorrhynchini and Erotinae, most specifically the pronotum with multiple carinae forming a 
pattern of multiple areolae(Kazantsev 2012a, 2012b; Sklenarova et al. 2014). The pectinate male 
antenna of Prototrichalus, present in some Metriorrhynchini, excludes it from being placed in 
the Erotinae, which have filiform or subserrate antennae (Kazantsev 2012a, 2012b; Sklenarova et 
al. 2014; Bocek and Bocak 2017; Bocek and Adamkova 2019).  
Additionaly, with the Metriorrhynchini, Prototrichalus shares the presence of four 
primary distinct elytral costae, with costa I short, specifically present in members of the 
trichaline group (Bocek and Bocak 2017). However, Prototrichalus is very different from any 
extant genus of Metriorrhynchini, lacking the secondary elytral costae and reticulation present in 
members of this tribe. The morphologically most similar genus is the trichaline genus 
Schizotrichalus Kleine, 1926, but despite the superficial similarity between these genera, 
Prototrichalus has a very different habitus and only convergently resembles Schizotrichalus. 
Prototrichalus exhibits a unique mixture of lycid characters states, not currently known 
by us to co-exist in modern taxa. Because of this, we choose to place Prototrichalus as incertae 
sedis in the Metriorrhynchini, as it cannot be placed in any of the current subtribes, in full 
understanding of the weakness of our conclusion. An alternative choice would be to erect a new 
Lycidae subfamily, proposing that Prototrichalus is a basal lineage, however, at only 100 Ma 
old, it is not of an age to be ancestral, as these fossils are at least 1/3 of the way from the most 
recently proposed origin of the lycids to today (McKenna et al., 2019).  
Metriorrhynchini as a recognizable group in the mid-Cretaceous 
The Metriorrhynchini are a clade with a Palaeotropical distribution, that hypothetically 
began its diversification in Eastern Gondwana (Sklenarova et al. 2013). Sklenarova et al. (2013) 
supported an origin of the group in the late Cretaceous using as their starting point the only 
calibrated publication available at the time by Bocak et al. (2008). Bocak et al. (2008) proposed 
the first dated phylogeny of Lycidae based on a penalized likelihood approach, a relaxed-clock 
method (Ho et al., 2005),  and set the in-group age arbitrarily to 100 Ma (Bocak et al. 2008, 
Supplementary Figure S3) estimating Metriorrhynchini to be as old as 60.8±2.36 Ma.   
Sklenarova et al. (2013, 2014) and Bocek and Bocak (2019), using Bocak et al. (2018) as 
a starting point for their own studies, added further DNA and morphology data in their analyses 
and were able to hypothesize a more in-depth evolutionary relationship of Metriorrhynchini and 
date subsequent clades within the in-group. Some of the trichaline lineages estimated to be as old 
as 31.95±3.02 Ma for Trichalus+Microtrichalus Pic, 1921; 26.75±3.02 Ma for Leptotrichalus 
Kleine, 1925, and as old as 51.78±3.02 Ma for the clade containing Trichalus sp., Microtrichalus 
spp., Leptotrichalus spp., Synchonnus sp. and Wakarumbia spp. (Sklenarova et al. 2013). Bocek 
and Bocak (2019), in a similar but slightly different group delimitation, retrieved very similar 
age estimates for the trichaline lineage, with an estimation of the origin of the group of at least 
50 Ma.  
The discovery and description of Prototrichalus and its three species provides direct 
evidence of Metriorrhynchini as a recognizable group in the mid-Cretaceous, earlier than the 
original predictions in the Late Cretaceous by Bocak et al. (2008) and the studies that followed. 
Future phylogenetic analysis of Metriorrhynchini using Prototrichalus as a calibration point 
should dramatically change the current estimation dates for the tribe and how we understand the 
origin, dispersal and evolutionary history of the group. 
Concluding Remarks 
Prototrichalus exhibits a unique mixture of lycid characters states, not known to us to co-
exist in any modern Lycidae, and we choose to place it as incertae sedis in the Metriorrhynchini 
based on similarities on the pronotum and antennae. The discovery of Prototrichalus provides 
direct evidence of Metriorrhynchini as a recognizable group in the mid-Cretaceous, pushing the 
origins of the group to be at least 40 Ma beyond what has been previously discussed. 
Acknowledgments  
The authors wish to express their gratitude to the editor, E. Koutsoukos and to the two 
anonymous reviewers who greatly contributed for the improvement of this paper. FMO is 
grateful to Bárbara and Mauricio Odifredi for sending to him some of the specimens used in this 
study and to Dr. Reyes Peña Santiago (University of Jaén, Spain) for his help with the 
photographs of his specimens. VSF is grateful to Conselho Nacional de Desenvolvimento 
Científico e Tecnológico (CNPq) of Brazil for a PhD scholarship (process 202559/2015-7) and to 
the Idea Wild Project Award, that allowed him to acquire part of the photographic equipment 
utilized in this study. MAB gratefully acknowledges Dr. Mei-Ying Lin for her donation of 
multiple amber fossils to this study. MAI thanks Ladislav Bocak (Palacký University Olomouc, 
Czech Republic) for useful discussions about the manuscript in an earlier form. This is a 
contribution of the Montana Agricultural Experiment Station. 
References 
Bocak, L., Bocakova, M. 1990. Revision of the suprageneric classification of the family Lycidae 
(Coleoptera). Polskie Pismo Entomologiczne 59, 623–676.  
Bocak, L., Bocakova, M., 2008. Phylogeny and classification of the family Lycidae (Insecta: 
Coleoptera). Annales Zoologici 58, 695–720.  
Bocak, L., Bocakova, M., 2010. 4.11 Lycidae Laporte, 1836.  Pp. 114-123. In Leschen, R. A.B., 
Beutel, R.G. , Lawrence, J.F. Handbook of Zoology, Coleoptera, volume 2. Morphology 
and Systematics (Elateroidea, Bostrichiformia, Cucujiformia partim). DeGruyter, Berlin. 
Bocak, L., Bocakova, M., Hunt, T., Vogler, A.P., 2008. Multiple ancient origins of neoteny in 
Lycidae (Coleoptera): consequences for ecology and macroevolution. Proceedings of the 
Royal Society B: Biological Sciences 275, 2015–2023. 
Bocak, L., 2002. Revision and phylogenetic analysis of Metriorrhynchinae. European Journal of 
Entomology, 99, 315–351.  
Bocak, L., Li, Y., Ellenberger, S., 2019. The discovery of Burmolycus compactus gen. et sp. nov. 
from the mid- Cretaceous of Myanmar provides the evidence for early diversification of 
net-winged beetles (Coleoptera, Lycidae). Cretaceous Research, 99, 149–155. 
Bocek, M., Adamkova, K., 2019. New species of Moluccan trichaline net-winged beetles, with 
remarks on the phylogenetic position and distribution of Schizotrichalus (Coleoptera: 
Lycidae: Metriorrhynchinae). Zootaxa 4623, 341–350 
Bocek, M., Bocak, L., 2017. The comparison of molecular and morphology-based phylogenies 
of trichaline net-winged beetles (Coleoptera: Lycidae: Metriorrhynchini) with description 
of a new subgenus. PeerJ 5, e3963.  
Bocek, M., Bocak, L., 2019. The origins and dispersal history of the trichaline net-winged 
beetles in Southeast Asia, Wallacea, New Guinea and Australia. Zoological Journal of the 
Linnean Society 185, 1079–1094. 
Cruickshank, R.D., Ko, Ko, 2003. Geology of an amber locality in the Hukawng Valley, 
Northern Myanmar. Journal of Asian Earth Sciences 21, 441– 455. 
Ferreira, V.S., 2015. A new species of Acroleptus Bourgeois (Coleoptera: Lycidae) from the 
Brazilian Amazonian rainforest, with a note on its homonymy with Acroleptus Cabanis 
(Aves). Zootaxa 3949, 297–300. 
Ferreira, V.S., 2016. A revision of the genus Macrolygistopterus Pic, 1929 (Coleoptera, Lycidae, 
Calochromini). Zootaxa 4105, 321–338.  
Ferreira, V.S., Ivie, M.A., 2017. The first fossil species of the extant genus Cessator Kazantsev 
(Coleoptera: Lycidae): a new leptolycini from Dominican Amber. The Coleopterists 
Bulletin 71, 57–60. 
Ferreira, V.S., Ivie, M.A., 2018a. A Review of the Nearctic Genus Lucaina Dugès, 1879 
(Coleoptera: Lycidae: Lycinae: Calochromini), with Descriptions of Two New Species. 
The Coleopterists Bulletin 72, 393–406. 
Ferreira, V.S., Ivie, M.A., 2018b. A revision of Lycinella Gorham, 1884 with the description of 
six new species (Coleoptera, Lycidae, Calopterini). ZooKeys 792, 69–89.  
Ho, S.Y.W., Phillips, M.J., Drummond, A.J., Cooper, A., 2005. Accuracy of Rate Estimation 
Using Relaxed-Clock Models with a Critical Focus on the Early Metazoan Radiation. 
Molecular Biology and Evolution 22 (5), 1355–1363. 
Hunt, T., Bergsten, J., Levkanicova, Z., Papadopoulou, A., John, SO, Wild, R., Hammond, P.M., 
Ahrens, D., Balke, M. , Caterino, M.S., Gómez-Zurita, J., Ribera, I., Barraclough, T.G.,  
Bocakova, M., Bocak, L., Vogler, A.P., 2007. A comprehensive phylogeny of beetles 
reveals the evolutionary origins of a superradiation. Science 318, 1913–1916. 
Kania, I., Wang, B., Szwedo, J., 2015. Dicranoptycha Osten Sacken, 1860 (Diptera, Limoniidae) 
from the earliest Cenomanian Burmese amber. Cretaceous Research, 52, 522–530. 
Kazantsev, S.V., 2005. Morphology of Lycidae with some considerations on evolution of the 
Coleoptera. Elytron 17, 49–226. 
Kazantsev, S. V., 2012a. New taxa and a checklist of Afrotropical Metriorrhynchini (Coleoptera: 
Lycidae), with a note on biogeography of the tribe. Russian Entomological Journal 21, 
23–33. 
Kazantsev, S. V., 2012b. A review of Erotinae and Dictyopterinae (Coleoptera: Lycidae) with 
description of new taxa and a note on biogeography of the subfamilies. Russian 
Entomological Journal, 21, 395–414. 
Kazantsev, S. V., 2017. New leptolycines from Ecuador and Peru (Coleoptera: Lycidae). Russian 
Entomological Journal 26, 127–146. 
Kazantsev, S., 2019. Protolycus gedaniensis gen. et sp. nov., the first Baltic amber representative 
of Lycini (Coleoptera: Lycidae: Lycinae). Palaeoentomology 002, 327–332. 
 
Kleine, R., 1926. Coleoptera Lycidae. In: Beaufort, L.F., de Pulle, A.A., Rutten, L. (Eds.) Nova 
Guinea. Résultats des expéditions scientifiques à la Nouvelle Guinée. Vol. XV Zoologie. 
Livraison II. E.J. Brill, Leiden, 91–195. 
 
Kusy, D., Motyka, M., Bocek, M., Masek, M., Bocak, L.. 2019. Phylogenomic analysis resolves 
the relationships among net-winged beetles (Coleoptera: Lycidae) and reveals the parallel 
evolution of morphological traits. Systematic Entomology 44, 911-925. 
Laporte [=Castelnau] F.L.N.C., de, 1836. Études entomologiques, ou descriptions d’insectes 
nouveaux et observations sur la synonymie. Revue Entomologique 4, 5–60. 
Lawrence, J.F., Slipinski, A., Seago, A. E., Thayer, M.K., Newton, A.F., Marvaldi, A.E., 2011. 
Phylogeny of the Coleoptera based on morphological characters of adults and larvae. 
Annales Zoologici 61, 1–217. 
Linnaeus, C., 1758. Systema naturae per regna tria naturae, secumdum classes, ordines, genera, 
species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, 
reformata Laurentius Salvius, Holmiae (1758), p. 824. 
Li, Y., Pang, H., Bocak, L., 2018. A Review of the Neotenic Genus Atelius Waterhouse, 1878 
from China (Coleoptera: Lycidae). Annales Zoologici, 68, 351–356. 
Masek, M., Ivie, M.A., Palata, V., Bocak, L., 2014. Molecular phylogeny and classification of 
Lyropaeini (Coleoptera: Lycidae) with description of larvae and new species of 
Lyropaeus. Raffles Bulletin of Zoology 62, 136–145. 
Masek, M., Motyka, M., Kusy, D., Bocek, M., Li, Y., Bocak, L., 2018. Molecular phylogeny, 
diversity and zoogeography of net-winged beetles (Coleoptera: Lycidae). Insects 9, 154. 
McKenna, D.D., Wild, A.L., Kanda, K., Bellamy, C.L., Beutel, R.G., Caterino, M.S., Farnum, 
C.W., Hawks, C.D., Ivie, M.A., Jameson, M.L., Leschen, R.A.B., Marvaldi, A.E., 
McHugh, J.V., Newton, A.F., Robertson, J.A., Thayer, M.K., Whiting, M.F., Lawrence, 
J.F., Ślipiński, A., Maddison, D.R., Farrell, B.D., 2015. The beetle tree of life reveals that 
Coleoptera survived end-Permian mass extinction to diversify during the Cretaceous 
terrestrial revolution. Systematic Entomology 40, 835–880. 
McKenna, D.D., Shin, S., Ahrens, D., Balke, M., Beza-Beza, C., Clarke, D.J., Donath, A., 
Escalona, H.E., Friedrich, F., Letsch, H., Liu, S., Maddison, D., Mayer, C., Misof, B., 
Murin, P.J., Niehuis, O., Peters, R.S., Podsiadlowski, L., Pohl, H., Scully, E.D., Yan, 
E.V., Zhou. X., Ślipiński, A., Beutel, R.G., 2019 .The evolution and genomic basis of 
beetle diversity. Proceedings of the National Academy of Sciences 116, 24729-24737. 
Motyka, M., Masek, M., Bocak, L., 2017. Congruence between morphology and molecular 
phylogeny: the reclassification of Calochromini (Coleoptera: Lycidae) and their dispersal 
history. Zoological Journal of the Linnean Society 180, 47–65. 
Shi, G., Grimaldi, D.A., Harlow, G.E., Wang, J., Wang, J., Yang, M., Lei, W., Li, Q., Li, X., 
2012. Age constraint on Burmese amber based on UePb dating of zircons. Cretaceous 
Research 37, 155–163. 
Sklenarova, K., Chesters, D. Bocak, L., 2013. Phylogeography of poorly dispersing net-winged 
beetles: a role of drifting india in the origin of Afrotropical and Oriental fauna. PLoS One 
8 (6), e67957.  
Sklenarova, K., Kubecek, V., Bocak, L., 2014. Subtribal classification of Metriorrhynchini 
(Insecta: Coleoptera: Lycidae): an integrative approach using molecular phylogeny and 
morphology of adults and larvae. Arthropod Systematics and Phylogeny 72, 37–54. 
Tihelka, E., Huang, D., Cai, C., 2019. A new genus and tribe of Cretaceous net-winged beetles 
from Burmese amber (Coleoptera: Elateroidea: Lycidae). Palaeoentomology 2, 262–270. 
Toussaint, E.F.A., Seidel, M., Arriaga-Varela, E., Hajek, J., Kral, D., Sekerka, L., Short, A.E.Z., 
Fikacek, M., 2016. The peril of dating beetles. Systematic Entomology 42, 1–10. 
Zhang, S.Q., Che, L.H., Li, Y., Dan, L., Pang, H., Slipinski, A., Zhang, P., 2018. Evolutionary 
history of Coleoptera revealed by extensive sampling of genes and species. Nature 
Communications 9, 205. 
 
 
Figure Captions 
 Figure 1. Prototrichalus sepronai sp. nov. Holotype MTEC 057001. A. Dorsal habitus. B. 
Pronotum and terminal maxillary palpomere details. Paratype MTEC 057002. C. Lateral view 
and antennae. D. Elytral costae III and IV detail; elytral punctuation detail. E. Lateral view and 
antennae. F. Antennae and terminal maxillary palpomere details. Scale bars: 2 mm. 
Figure 2. Prototrichalus milleri sp. nov. Holotype MTEC 057003. A. Dorsolateral habitus. B. 
Elytral costae III and IV detail; elytral punctuation detail; tarsus detail. C. Ventrolateral view. D. 
Maxillary palp detail. E. Pronotum and maxillary palpomere details. Scale bars: 2 mm. 
Figure 3. Prototrichalus meiyingae sp. nov. Holotype MTEC 057004. A. Dorsolateral habitus. 
B. Elytral costae III and IV details. C. Ventral view. D. Ventral view of the head and antennae. 
E. Female genitalia and abdomen detail. Scale bars: 2 mm.