Taxonomic Notes

Introduction

BugGuide states that there are about 25,000 described species of Coleoptera in North America, representing 4 suborders and about 130 families. In Michigan, we have found valid beetle species from 114 families. The suborder Archostemata comprises only two families worldwide, the Cupedidae & Micromalthidae, and both occur in Michigan. For the suborder Adephaga, of the 11 families worldwide and eight in North America north of Mexico, six have representatives in Michigan. The suborder Myxophaga consists of four families worldwide of which two occur in the western and southern regions of the U.S., but neither family reaches Michigan. Within the suborder Polyphaga, there are Michigan beetle species from 106 families.

There have been many recent taxonomic changes in the Coleoptera. BugGuide states that the taxonomic arrangement appears settled at the superfamilial levels, but that many groups once treated as families are now subfamilies, and vice versa.  Some of the recent changes listed by BugGuide in higher taxonomy that affect Michigan beetles include:

Scydmaenidae sunk into Staphylinidae

Ceratocanthidae sunk into Hybosoridae

Anobiidae are now Ptinidae

Members of the cerylonid clade recently moved from Cucujoidea to a separate superfamily, Coccinelloidea, and underwent massive splitting

Brachypteridae are now Kateretidae

Languriidae sunk into Erotylidae

Cybocephalidae restored

Colydiidae sunk into Zopheridae

Bruchidae sunk into Chrysomelidae

Rhysodidae are increasingly treated within Carabidae, but retained here as a separate family

Ithyceridae sunk into Brentidae

Disteniidae split from Cerambycidae

Scolytidae sunk into Curculionidae

Apioninae moved from Curculionidae to Brentidae

Families with taxonomic issues

In several groups BugGuide does not use subspecies even though ITIS (itis.gov) and others continue to do so (e.g., Coccinella transversoguttata and Coleothorpa dominicana).  At present, we have mixed the two approaches--usually reporting subspecies if the source did, but not adding subspecies when the source did not, even when only one subspecies occurs in the Michigan area.  This matter may deserve to be addressed and resolved.

Anamorphidae

Newly raised to family level by Robertson et al. (2015).  Bouchard (2011) still had it as a subfamily within Endomychidae, and listed no tribes for it.

Brentidae

The subfamily Apioninae is divided into tribes very differently by Bouchard (2011) than in Arnett et al. (2002).  BugGuide continues to follow Arnett et al. (2002), but we have opted to follow the newer classification here.

        The former genus Apion has been divided into many genera, and most North American species have been placed in the new genera.  We have not been able to find a current name for Apion (Certapion) parallelum.  Thus, in our list it remains as Apion parallelum.

Carabidae

Bousquet (2012) did a marvelous job with the terrestrial Adephaga for all of North America north of Mexico, and although his assignments of species to subfamilies and tribes differs from other sources for some species, we follow his nomenclature and usage except in the Cicindelinae where we follow Pearson et al. (2015).

Cerambycidae

In the genus Brachyleptura there is some disagreement as to whether brevis or champlaini is the name to be used for that species. We follow BugGuide and use the latter.

        The genus Oberea is placed in the tribe Phytoeciini by BugGuide, in a tribe of its own (Obereini) by Bouchard et al. (2011) and Bezark (2019).  We have opted for Obereini.

        BugGuide and GBIF recognize the genus Etorofus while itis.gov does not. Species known from Michigan that have been transferred to Etorofus are Leptura plebeja and Leptura subhamata.  Bousquet (2013) uses Pedostrangalia for these species.  We follow BugGuide and GBIF by placing these two species in Etorofus.

Chrysomelidae

The genus Calligrapha poses challenges when dealing with museum specimens as many of the species have quite variable elytral markings and are best separated based on larval host plant.  This genus deserves serious additional study.

Cleridae

Two very different subfamily arrangements for the Cleridae appear in Opitz (2010) and Bouchard (2011).  We follow the one proposed by Opitz (2010) as does BugGuide.  That classification does not recognize tribes within the subfamilies.

        In the genus Enoclerus some sources recognize two or three subspecies while others use none.  At present we're ignoring subspecies, but may change.

Coccinellidae

Bouchard (2011) has only two subfamilies for this family with all of the subfamilies used in Arnett et al. (2002) reduced to tribes within the Coccinellinae; however, they pulled the Microweiseini out of the Sticholodinae and raised that group to subfamily level.  BugGuide continues to follow Arnett et al. (2002), and that is what we have done here also.

        BugGuide recognized no subspecies for Coccinella transversoguttata whereas GBIF has three.  At present we have a mix of the two systems.

Cryptophagidae

In the genus Ephistemus we have either E. globulus or E. apicalis, whichever is the accepted name.  Sources disagree.

Cucujidae

Thomas (2004) states that the Palaearctic Pediacus depressus (Herbst) does not occur in North America, and that records for that species refer to P. subglabrus LeConte.  BugGuide lists both for eastern North America.  We are rejecting the P. depressus records of Hubbard and Schwarz (1878) for Michigan.

Curculionidae

BugGuide follows Atkinson (2020) and recognizes only two tribes in the Scolytinae. Their system is based on Wood (1982).  All of their subtribes (except Corthylina & Pityophthorina) are treated as tribes by Bouchard (2011), Leschen and Beutel (2014) and Hulcr et al. (2015).  Very recently Johnson et al. (2020) broke Cryphalini into several tribes.  Atkinson (personal communication) is in the process of updating his website to reflect the more recent classification and recommended we follow them in our list of Michigan beetles, which we have done.

Cybocephalidae

Newly raised to family level by Cline et al. (2014).  Bouchard (2011) still had it as a subfamily within Nitidulidae, and listed no tribes for it.

Disteniidae

Arnett et al. (2002) treats this as a subfamily in Cerambycidae while Bouchard (2011) considers it a family.  BugGuide follows Arnett et al. (2002) but comments that it is "usually treated as a separate family."  The only species present in the eastern U.S. is very distinctive and not easily confused with anything else.  Thus we find it surprising that Hubbard and Schwartz (1878) reported it from the Detroit area, yet there are no other known records for the state.

Dytiscidae

The higher classification within the Dytiscidae remains in flux.  Larson et al. (2000) recognized seven subfamilies in America north of Mexico whereas BugGuide recognizes eight (as of 2020).  Subfamily Hydrotrupinae in Larson et al (2000) is a genus in Agabinae on BugGuide. BugGuide largely follows Miller and Bergsten (2016) except regarding Cybister and Megadytes, which Miller and Bergsten (2016) have in the subfamily Cybisterinae whereas BugGuide and Larson et al. (2000) include them as a tribe in the Dytiscinae.  Also, BugGuide uses tribes in fewer families than the other two sources.  In this list we follow the subfamily classification used in BugGuide but have added tribal names as used in Nilsson (2015) and Miller and Bergsten (2016).

        For Coptotomus longulus BugGuide says "lenticus was once considered a separate species but there is some evidence of hybridization with longulus" so they dropped lenticus completely without citing a source.  Larson et al. 2000 lists both subspecies as does GBIF & Wikipedia (as of February 2021).  Hybridization w/longulus would suggest subspecies status is more appropriate for lenticus.  Thus our list includes both C. longulus longulus and C. longulus lenticus since both forms occur in Michigan.

Elateridae

The genus Ctenicera has been divided into several genera.  According to BugGuide only kendalli will remain in Ctenicera, but to date neither pyrrhos or virens have been assigned to a new genus.  Thus, in our list the latter two species are still listed as Ctenicera.  In addition, if acutipennis has been assigned to a new genus, we have not found that information.

Erotylidae

Higher classification within this family continues to evolve.  BugGuide follows Węgrzynowicz (2002) by having only two subfamilies, Xenoscelinae and Erotylinae, with the latter divided into five tribes of which one is the former family Languridae.  Bouchard (2011) has the former Languridae as its own subfamily.  

Euxestidae

This group was recently raised to family level by Robertson et al. (2015).  It was formerly considered a subfamily within Cerylonidae, which is how Bouchard (2011) has it.

Histeridae

The main difficulty in the Histeridae is the paucity of recent publications mentioning Michigan records.  About 3/4 of the species in our list for Michigan are reported only in pre-1925 publications or in Downie and Arnett (1996).

Lampyridae

About 50 species of Photuris are known from the U.S., but most cannot be identified except by flash patterns.  Our list includes ten species reported from Michigan, but for six we say the record needs confirmation or is doubtful, as flash patterns have not been reported for most Michigan observations.

Lycidae

The higher classification of this family is also unsettled.  BugGuide follows American Beetles (Arnett et al., 2002) whereas Bouchard (2011) uses a different system.  The subfamilies Calochrominae, Erotinae and Platerodinae of Arnett et al. (2002) are all reduced to tribes within Lycinae by Bouchard (2011), but the genus Dictyoptera which Arnett et al. (2002) have in Erotinae has been removed by Bouchard (2011) and placed in the tribe Dictyopterini within a new subfamily Dictyopterinae.  In our list, we follow the newer system of Bouchard (2011).  However, for several genera (e.g., Grenarus & Leptoceletes) we do not know which tribe they belong in.

Lymexylidae

Sources disagree on the generic placement of our only species, with BugGuide placing lugubris in Hylecoetus whereas GBIF & itis.gov have it in Elateroides.  In this case we are following GBIF & itis.gov.

Melyridae

In spite of Marshall (1951) saying Pseudebaeus (now Hypebaeus) oblitus is merely a dark color phase of apicalis, BugGuide continues to recognize both and says apicalis is only in the SE. GBIF recognizes only apicalis.  We have followed BugGuide and are calling the Michigan specimens H. oblitus.

Murmidiidae

Also recently raised to family level by Robertson et al. (2015).  Considered by some to be a subfamily (Murmidiinae) within Cerylonidae.

Mycetaeidae

Used to be included as a subfamily (Mycetaeinae) in Endomychidae.  Also recently raised to family level by Robertson et al. (2015).

Mycetophagidae

Although GBIF places the species didesmus (Say) in the genus Litargus, BugGuide follows Lawrence et al. (2014) and places it in the subgenus Paralitargus of Mycetophagus.  We have followed BugGuide.

Nemonychidae/Cimberidae/Cimberididae

The two Michigan species in this group both belong to the genus Cimberis which all recent revisers place in the tribe Cimberidini, but there is disagreement as to what family and subfamily names apply.  Arnett et al. (2002) and Bouchard (2011) use the family Nemonychidae and subfamily Cimberidinae.  BugGuide, apparently following Leschen and Beutel (2014), have retained the family name Cimberidae.  Bouchard, however, states that Cimberidae Gozis, 1882 was placed on the Official Index of Rejected and Invalid Family-Group Names in Zoology and Cimberididae Gozis, 1882 placed on the Official List of Family-Group Names in Zoology.  We have elected to follow Bouchard (2011) and are using the family Nemonychidae.

Nitidulidae

The speciose genus Epuraea is divided into 17 subgenera worldwide, of which at least five are represented in North America.  While some of our species have been assigned to a subgenus, others have not.  Those for which we have found no subgeneric assignment have the subgenus labelled as "incerta sedis."

Also, Cline et al. (2014) concluded that Prometopia and several related genera that had been placed within the tribe Nitidulini deserved status as a subfamily.  Thus we have it in Prometopinae, a name that Bouchard (2011) listed under Nitidulini.

        GBIF and ITIS place the species niger (Say) in the genus Carpophilus, whereas BugGuide places it in Colopterus.  Parsons (1943) put this in Colopterus and most authors subsequently followed that, and BugGuide and D&A list Parsons as reference so that is why they may have it in Colopterus. Interestingly, Carpophilus and Colopterus are now in different subfamilies, with supposedly distinct characters to separate them, so it should be easy to place niger in one or the other genera. However, there doesn’t seem to be any published record transferring or returning niger to Carpophilus.  GBIF and ITIS are more likely correct & we have followed them, but it might be another consensus issue.  

Phalacridae

In his genus-level revision of the Phalacridae of the world Gimmel (2013) chose to not assign genera to the two previously recognized subfamilies, even though his analyses supported the traditional separation.  We follow his classification here.  By the previous classification (as in Bouchard, 2011) all known Michigan species would be placed in subfamily Phalacrinae.

Ptinidae

Bouchard (2011) recognizes no tribes within the subfamilies Anobiinae, Dorcatominae, Ptilininae or Ernobiinae whereas BugGuide and Arnett et al. (2002) list seven tribes for Anobiinae in America north of Mexico, four for Dorcatominae and three for Ernobiinae.  In this case we follow Arnett et al. (2002) and include their tribe names in our list.

        BugGuide considers Ptinus clavipes to be a jr. syn. of P. latro, whereas GBIF, itis.gov and Arango and Young (2012) consider both to be valid species.  We are listing both as occuring in Michigan.

Silphidae

Sikes et al. (2013) argue that the Nicrophorus species found across all of northern North America, and which has been considered conspecific with the palearctic N. vespilloides Herbst, is in fact a distinct species.  They resurrected the name N. hebes (Kirby) for this species.  BugGuide (as of Feb. 2021) still uses N. vespilloides.  As of now our list has it both ways.

Silvanidae

A well know common species goes under two different names in the literature and in collections: Telephanus atricapillus Erichson and T. velox (Haldeman).  Thomas (1993) states that although atricapillus is the older name, it is treated as a nomen nudum by most authors because Erichson did not explicitly describe the species when he described the genus Telephanus, although he did propose the name atricapillus.  BugGuide uses the name atricapillus whereas GBIF and itis.gov use velox.  We choose to follow GBIF for Michigan in this case.

Staphylinidae

In the very large genus Stenus (subfamily Steninae) some sources use subgenera while others do not.  BugGuide does use subgenera, but at present their site includes only a small fraction of the species recorded for Michigan.  Herman (2001) does not directly state the subgenus for any of the species, but for many he reports the subgenus that earlier authors used in their publications.  When available we have used those subgeneric designations.

        For Deinopsis americana some sources use () on Kraatz and others do not.  Apparently Agassiz emended Deinopsis to Dinopsis in 1846, and Kraatz described americanus in Dinopsis.  We do not know the rules well enough to know whether () are required in this case.  At the moment we have it both ways in our list.

        The genus Euconnus poses significant challenges for us.  Over 100 species in 10 subgenera are known from the Nearctic, yet BugGuide includes only five species.  For the past 25 years or so S. T. O'Keefe has been working on the genus (and others in the subfamily), but for most species very little distributional data has been published.  Our placement of species in subgenera is inconsistent and needs review.

Trogidae

The genus long known as Trox has been divided into several genera by Nikolajev (2016).  GBIF follows the new classification whereas BugGuide does not.  So far we have followed BugGuide but may reconsider.

Families with very incomplete Michigan records

While some beetle families or subfamilies are well studied and have received great attention in recent years, quite the opposite is true for others.  The Scolytinae (Curculionidae) may be the best known group with Cerambycidae and Cicindelinae (Carabidae) not far behind. At the other extreme we find the Scydmaeninae, Paederinae and Aleocharinae (Staphylinidae) as three of the least known groups.  Other very poorly known groups include most of the fungivorous and spore-feeding families with small to tiny specimens such as Ptiliidae, Corylophidae, Cryptophagidae, Clambidae, Sphindidae, etc. (check this).

Cryptophagidae

Only 12 species are reported from Michigan, and most of those records are from the 1800s. Downie & Arnett (1996) include 58 species for the Northeast which suggests that our knowledge of this family is woefully lacking.

Nomenclatural issues

Several sources were used to determine the currently accepted name for each species. In most cases the final authority was the Integrated Taxonomic Information System (ITIS) (http://www.itis.gov), but some groups are not treated there (or the treatment is out of date).  For those we relied on GBIF (https://www.gbif.org/) and/or BugGuide (https://bugguide.net) and sources cited there.  If neither of those sites included the taxon, then we used the name found in the most recent publication by a reputable authority.  

Additional Notes

Subgenera in Agonum and Amara (and maybe others), as well as the subfamily breakdown of Carabidae, differ between Bousquet & BugGuide. We have mixed the two in our list.

        In addition, we often (1) did not use subfamilies in smaller families even when they existed, (2) cited only the most authoritative source for each species, and (3) included the scientific name used in source only when it differed from the currently accepted name. 

Acknowledgements

We thank T.H. Atkinson for advice regarding the current tribal classification of the Scolytinae, and P.W. Messer for providing data on and identification services for Caraboidea.