New Records of Featherwing Beetles (Coleoptera: Ptiliidae) in North America

New continental, national, provincial and state records of 34 species of Ptiliidae reported from North America are briefly listed, 20 of which belong to Acrotrichis Motschulsky. Eight European/ Palaearctic species (Oligella foveolata (Allibert), Ptiliolum fuscum (Erichson), Ptiliola kunzei (Heer), Ptinella aptera (Guérin-Meneville), P. britannica Matthews, P. johnsoni Rutanen, Acrotrichis parva Rosskothen, A. silvatica Rosskothen) were previously not recorded on the North American continent.

Fourteen species are new to Canada and 12 new to U.S.A. New or previously dubious provincial and state records are confirmed for Canada (96) and for U.S.A. (133). Acrotrichis fungi (Abdullah and Abdullah), previously established as a nomen dubium, should be removed from the Canadian list of Coleoptera. An updated checklist of North American ptiliid genera is presented.

A tabulated summary of ptiliid species common to North America and either Europe or the Palaearctic is presented. Species are ordered according to their supposed origin (recent introductions or indigenous elements). Species of the beetle family Ptiliidae (Featherwing beetles) are obscure, small creatures primarily found in leaf litter and rotten organic substances all over the world.

Although often common they have generally been neglected by collecting coleopterists, and larger collections of Ptiliidae are rare even among public museums. From America north of Mexico some 110 valid species (ca. 135 nominal) are known, the majority having been described more than 100 years ago (Casey, Haldeman, LeConte, Matthews, Motschulsky). The actual number of species is estimated to exceed this figure two- or even threefold.

My own collection holds 160 North American species belonging to genera already described (cf. Table 1). In addition there are dozens of species which cannot be assigned to any known genus.

Dybas (1978) estimated the number of species to exceed 200. Modern revisions are lacking for most genera, the exceptions primarily being H. S. Dybas’ works on Bambara Vuillet (Eurygyne Dybas) (Dybas 1966), Ptinellodes Matthews (Dybas 1978 a) and Ptiliopycna Casey (Dybas 1978 b), and Seevers’ and Dybas’ (1943) revision of the myrmecophilic genera of Cephaloplectinae. Monotypic genera (Porophila Dybas; Hydnosella Dybas; Cylindroselloides Hall, Throscoptiloides Hall) were treated by Dybas (1956, 1961) and Hall (1999).

Of the taxa mentioned only Bambara occurs in the Palaearctic region. Sundt (1958) showed that most ptiliid species cannot be identified with certainty without consideration of the structure and configuration of the genitalia. He especially stressed the importance of using type specimens to establish species identities primarily based on genitalic characteristics, thereby laying an unequivocal foundation for species identification.

For that reason practically all previous non-type records of American Ptiliidae cited in the literature before Seevers and Dybas (1943) cannot be uncritically accepted without thorough rechecking, which involves preparing for the genitalia and comparison with primary type specimens. In addition, works, keys and catalogues of younger age that uncritically cite older records are unreliable and thus of limited value (e.g., Arnett 1968; Poole and Gentili 1996; in part also Downie and Arnett 1996). 369 Table 1.

Checklist of valid generic names of Ptiliidae of America north of Mexico. The genera are arranged alphabetically. Synonyms are omitted (Dilinium Casey ¼?

Micridium Motschulsky; Ptiliodina Casey ¼? Pteryx Matthews; cfr. Dybas (1990); Hall (2001); Johnson (2001); Poole and Gentili (1996)).

Acrotrichis Motschulsky, 1848 Paralimulodes Bruch, 1919 Actidium Matthews, 1868 Porophila Dybas, 1956 Actinopteryx Matthews, 1872 Ptenidium Erichson, 1845 Bambara Vuillet, 1911 Pteryx Matthews, 1858 Cylindrosella Barber, 1924 Ptiliola Haldeman, 1848 Cylindroselloides Hall, 1999 Ptiliolum Flach, 1888 Hydnosella Dybas, 1961 Ptiliopycna Casey, 1924 Limulodes Matthews, 1867 Ptilium Gyllenhal, 1827 Micridium Motschulsky, 1869 Ptinella Motschulsky, 1844 Millidium Motschulsky, 1855 Ptinellodes Matthews, 1872 Motschulskium Matthews, 1872 Smicrus Matthews, 1872 Nanosella Motschulsky, 1869 Suterina Dybas, 1981 Nephanes Thomson, 1859 Throscoptilium Barber, 1924 Nossidium Erichson, 1845 Throscoptiloides Hall, 1999 Oligella Motschulsky, 1869 A new critically checked catalogue or checklist of North American Ptiliidae is thus needed.

My own preliminary checklists of Ptiliidae of Canada and of U.S.A. have not incorporated most older records. Scanning new material reconfirmed in some instances old literature records (see list below). However, much work needs to be done before a‘ ‘clean’’ list emerges.

As an example I have in preparation a revision of North, Central and South American Acrotrichis Motschulsky, the largest ptiliid genus, comprising about 20% of the total ptiliid species number in North America. The list of taxa below is a modest start and should be viewed in the light of that work. The majority of genera currently recorded from North America are of Holarctic or cosmopolitan distribution.

Following Dybas (1990) and Hall (1999, 2001), also including the Cephaloplectinae (Limulodinae), only seven out of 29 ptiliid genera seem restricted to North America (cfr. Table 1). Five of these belong to the Nanosellini.

These figures to a large extent reflect the influence of previous works by European nineteenth century students, who usually assigned North American species to wellknown European genera. Years ago Dybas stated that only a fraction of the actual number of North American ptiliid species had been named, and certainly some of them seemed to belong to already known genera of tropical distribution not occurring in Europe, or would need to have new genera erected.

Dybas (1990) also remarked that a few North American polytypic genera possibly should be split in two. Table 1 summarizes in a brief, updated checklist the current standing on the generic level of North American Ptiliidae (incl. Cephaloplectinae).

I have not attempted a systematic arrangement since the internal classification of Ptiliidae is still poorly known. The checklist builds partly on Dybas (1990), Hall (1999, 2001) and Johnson (2001) but was corrected for authors and dates. It should be contrasted with Poole and Gentili (1996) for spelling, years of description, included taxa, etc.

For the last 15 years I have scanned large amounts of ptiliid material, both from main sources of larger museum collections in North America and from minor collections of other origin. I can confirm the view of Dybas as cited above, although species-rich genera such as Acrotrichis, Ptenidium Erichson, Ptinella Motschulsky and Ptiliolum Flach, do in fact share a fair number of species with the European or Palaearctic realm.

As far as possible I have taken notes on records of species new to North America, Canada or U.S.A., and their provinces/states. Below is presented a condensed list of such records. I have put special emphasis on ptiliid species regarded as common to America north of Mexico and Europe or the Palaearctic region.

Additionally a few strictly Nearctic species have been included. Finds from geographical localities other than those cited below were seen for many states and species and were recorded for my personal files. For practical reasons only one record per state/province is cited.

Materials and

Methods

Material for this investigation was collected during my own field trips in Canada and U.S.A. and was supplemented by samples from the profuse collections of North American public museum as well as private collections of Ptiliidae generously put at my disposal, including a few European sources. During the course of study many thousands of specimens were studied, sexed and identified. This paper accounts for a part of that work.

Altogether 4,604 specimens of 34 species from Canada and U.S.A. are listed below. They are preserved as drymounts or in ethanol and were studied and identified according to modern practice, involving checking genitalia of critical species. Whole slide mounts proved unnecessary for proper species identification.

Genera and species within genera as presented below are given alphabetically. Species of Acrotrichis Motschulsky are listed according to their subgeneric and species group associations. In the species list states or provinces are given in bold style followed by original label data, including brief particulars on collecting and the number of specimens (if sexed).

Number of specimens (not sexed) and abbreviated name of collection(s) and preservation then follow in parenthesis. Material from the following public institutions and private collections were studied: BMNH (The Natural History Museum, London), CCC (coll. Claude Chantal, Québec), CJLC (coll.

J. L. Carr, Alberta), CKS (coll. Karl Stephan, Oklahoma), CMD (coll. Michael Darby, London), CNC (Canadian National Insect Collection, Ottawa), coll.

P. Paquin (Ottawa), EDNH (Entomological Museum, Durham, New Hampshire), ESNN (coll. E. Sundt, Norsk Institutt for Skogforsking at Ås, Norway), FMNH (Field Museum of Natural History, Chicago), HSLA (Public Health Service, Los Angeles), IVTA (Institut voor Taxonomie, Antwerpen), MCZ (Museum of Comparative Zoology, Harvard), MM (Manchester Museum, Manchester), MSUL (coll. M. Sörensson, University of Lund, Sweden), WUMB (J. B. Wallis Museum, University of Manitoba, Winnipeg).

Results Of 4,604 specimens examined 34 ptiliid species were identified: 3,306 representing 20 species belong to Acrotrichis Motschulsky. In all 1942 specimens of 30 species originate from Canada, 2,662 specimens of 28 species from U.S.A. Eight European/ Palaearctic species were previously not recorded in the New World (Oligella foveolata (Allibert), Ptiliolum fuscum (Erichson), Ptiliola kunzei (Heer), Ptinella aptera (Guérin-Meneville), P. britannica Matthews, P. johnsoni Rutanen, Acrotrichis parva Rosskothen, A. silvatica Rosskothen).

According to the checklist of Canadian Ptiliidae (Campbell 1991) an additional six species are new to Canada (Ptenidium speculifer Matthews, Smicrus filicornis (Fairmaire and Laboulbéne), Acrotrichis montandonii (Allibert), A. discolor (Haldeman), A. aspera (Haldeman) and A. longipennis (Casey)). The following additional species have not been recorded previously from U.S.A. to my knowledge: Ptenidium nitidum (Heer), Acrotrichis thoracica (Waltl), A. volans Motschulsky and A. intermedia (Gillmeister).

Many new state or province records are given, some of which undoubtedly echo previous unchecked findings. Altogether 96 Canadian province records and 133 U.S. state records are cited. Table 2.

North American Ptiliidae common to Europe, or of Holarctic distribution, divided into subgroups as to their supposed origin. Besides species mentioned in this paper also Bambara fusca (Dybas) and Ptiliolum spencei (Allibert) are grouped. INTRO-NA ¼ species introduced in North America, probably via Europe.

INTRO-EURO ¼ species introduced in Europe from North America, with rough time of introduction given in parenthesis. INDIG-HOL ¼ indigenous species of Holarctic distribution naturally occurring in North America.? ¼ species of uncertain origin. INTRO-NA INTRO-EURO Ptenidium pusillum (Gyllenhal) Ptenidium nitidum (Heer) Oligella foveolata (Allibert) Millidium minutissimum (W. and M.) Bambara fusca (Dybas) (1990’s) Acrotrichis cognata (Matthews) (1930’s) Acrotrichis josephi (Matthews) (1980’s) Acrotrichis henrici (Matthews) Ptiliolum spencei (Allibert) Acrotrichis sericans (Heer) Acrotrichis insularis (Mäklin) (1960’s) INDIG-HOL?

Ptiliola kunzei (Heer) Ptiliolum fuscum (Erichson) Ptinella aptera (Guérin-Meneville) Ptinella johnsoni Rutanen Ptiliola brevicollis (Matthews) Ptinella britannica Matthews Smicrus filicornis (F. and L.) Nephanes titan (Newman) Acrotrichis volans (Motschulsky) Acrotrichis parva Rosskothen Acrotrichis silvatica Rosskothen Acrotrichis intermedia (Gillmeister) Acrotrichis grandicollis (Mannerheim) Acrotrichis montandonii (Allibert) Acrotrichis thoracica (Waltl) Species of supposed European origin have for long been known in North America.

Some of them later proved to be incorrectly identified, others synonyms of already established species. Still a rather large proportion of species remain that share a common distribution with the Old World, either as a result of late introductions or being indigenous geographical elements. I believe it is of general interest to attempt a division of Holarctic Ptiliidae into subgroups which reflect their origin, either as recent introductions in one or the other continent, or as indigenous elements.

The list presented here, the first of its kind within Ptiliidae, only treats species mentioned in this paper. Table 2 summarizes common background knowledge about general distribution and ecology for the species mentioned here, and uses it for assigning species into subgroups which reflect their supposed origin and direction of spread. Although assignment to any group is uncertain for a few species, most neatly fall within one of three groups, as shown in Table 2.

Definition of the groups reflects the multidirectional transports between the continents which obviously have taken place within several groups of insects, including Ptiliidae, during the last centuries. Although some species apparently were introduced more or less recently (within the last hundred years) some might be of older origin, like Acrotrichis grandicollis (Mannerheim) in Europe, a species of uncertain origin possibly emanating from America and introduced to Europe during Columbian time.

As in other groups of Coleoptera late introductions usually display a typical discontinuous distribution pattern often concentrating in anthropogenic (man made) environments in populated areas. Six species hypothesized as late introductions from Europe into North America are listed in Table 2. They are all regarded as anthropophilic faunal elements, regularly occurring in man-made habitats such as compost, stable dung, haystacks, grass piles, garden refuse etc., rarely outside such habitats.

For the five species hypothesized as being late introductions in the opposite direction we are able also to specify in most cases the very decade of probable immigration (given within parenthesis). This is due to the intense and long term collecting of Ptiliidae in various parts of Europe. The third group contains elements of hypothesized indigenous occurrences on both continents (North America-northern Euroasia), while the fourth comprises species of uncertain or dubious origin.

This latter group contains some well-known anthropophilics of the first or second subgroup, whose supposed introductions in either direction seem to date further back in history (e.g., Acrotrichis grandicollis (Mannerheim), A. montandonii (Allibert), Nephanes titan (Newman)). Until subfossil remnants of medieval and prehistoric ages has been analyzed in greater detail their origin will remain dubious. Campbell (1991) and Poole and Gentili (1996) cited Acrotrichis fungi (Abdullah and Abdullah), originally described in a new genus Macdonaldium Abdullah and Abdullah, 1967 (¼ Acrotrichis Motschulsky, 1848), as a proper species.

Sundt (1968) previously showed that A. fungi is a nomen dubium because of incomplete description and lack of type material. The name is invalid and should be removed from current checklists. List of Species The genus Acrotrichis Motschulsky, 1848 is the most species-rich ptiliid genus in North America, the total number of valid species amounting to about 25, the real number, however, probably exceeding 50.

About a dozen or so common species display a wider distribution which extend into Europe and/or Asia, a few being truly Holarctic (cfr. Table 2). Some species are anthropophilics probably representing more or less recent introductions.

Most literature records of North American Acrotrichis are old and unreliable. Since previous identifications generally were made without consideration of genitalic structures such records should therefore be disregarded unless they were critically checked according to modern practice. While preparing for a revision of the North American species of Acrotrichis many new records (based on genitalia) have come to my attention, some of which are presented below.

New Canadian records have been checked against the recent Canadian catalogue (Campbell 1991) which principally only includes original type localities and a few modern records recently confirmed by C. Johnson (Johnson 1990). As for U.S.A. older, non-syntypical literature records of Acrotrichis have largely been neglected due to reasons given above. As a consequence some state records presented below will echo previous records from the literature, however now for the first time having been critically checked for according to modern practice involving the genitalia and therefore reliable (cfr.

Dybas 1990). In this context it is worth mentioning that species of Acrotrichis, as well as most other Ptiliidae, need not be routinely prepared as slide mounts according to the method of Dybas (1990) for lightly sclerotized species, but rather glued onto rectangular or triangular cardboards, or simply preserved in 70% ethanol permanently. This is because with some practice many species can quite easily be distinguished using external characters such as microsculpture, lustre, and even color, characters which are lost during the process of bleaching with KOH and other stronger agents.

Identification of Ptiliidae are best made during mounting and preparation when any chosen method of preparation can be applied (cfr. Johnson 1982). Unidentified material and/or excess specimens are best preserved in 70% alcohol.

Distributional records (states, provinces) are listed in a geographical sequence, starting North East and ending North West.