Predaceous Diving Beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska.

This extremely informative and useful volume covers Canada and Alaska in full and most of the United States. It includes 100 pages on larvae, with descriptions and keys to genera for all instars. The chief merit of the book is that it brings so much information together and makes species identification much easier as it replaces previous, more regionally limited works. The handbook also includes one new subfamily, one genus, and 15 new species, mostly in the genera Agabus and Hydroporus. Other novelties include new combinations, new synonyms, and lectotype and neotype designations. Generally, the keys include all or most species occurring in Canada and the US. All Canadian species are described in detail, and their distribution is presented on maps providing detailed records for Canada and Alaska, and statewise records for US. Exceptionally, all 55 Hydroporus species and 106 Agabus species recognized in North America including Mexico are described in detail. The new book will no doubt be used as a reliable source for all kinds of information. Consequently, there will be a high risk for the errors listed below to be duplicated if not corrected directly. Laccophilinae Gistel, 1856, instead of Bedel, 1881; and Hydroporinae Aubé, 1836, instead of Erichson, 1837. Acilius abbreviatus Aubé, 1838:134, predates Mannerheim 1843:219. Aubé gave his name as ‘Semisulcatus var. Abbreviatus’ and included a short description, which means that it is available as a species-group name. Most likely both descriptions refer to the same Alaskan material. Consequently, no new name is needed if Aubé is cited as author of abbreviatus. Hygrotus novemlineatus (Stephens, 1829) instead of 1828. Hydrocolus picicornis (J. Sahlberg, 1875) instead of 1873. Heterosternuta wickhami (Zaitzev, 1908:118) instead of 1907:114. Following Bousquet (1993, Ent. News 104:1-14) Coptotomus and C. serripalpus were both first described in 1830 and not in 1834. Same error for Hydroporus discicollis, and Rhantus gutticollis. Hydroporus arcticus, and H. geniculatus Thomson, 1856 instead of 1854. Hydroporus striola (Gyllenhal in Sahlberg, 1826:181) instead of 1827:393. The description was first published in Sahlberg’s Insecta Fennica as Hyphydrus (and not Hydroporus) striola. Hydroporus fortis, Cybister ellipticus, and C. explanatus LeConte, 1852 instead of 1851. Hydroporus levanderi J. Sahlberg, 1889 instead of 1888. Carrhydrus, and C. crassipes Fall, 1922 instead of 1923. Matus bicarinatus (Say, 1823) instead of 1825. Colymbetes dahuricus Aubé, 1837, instead of 1836. Hygrotus unguicularis (Crotch, 1874) is Holarctic with H. mongolicus (Jakovlev, 1899) as synonym (Nilsson 1995, Water Beetles of China 1:35–96). The Kamchatka record of Graphoderus perplexus Sharp, 1882 (Nilsson et al. 1999, Beitr. Ent. 49:107–131) adds this species to the Holarctic list. The new combinations presented explicitly in the book are valid, e.g. all Hydrocolus species. However, it seems that many new combinations are given although not marked as such. I here think of Heterosternuta, Neoporus, and Sanfilippodytes that lately have attained genus status in the absence of any work explicitly dealing with this question. All species not recently dealt with in larval descriptions or faunistic work most likely are given as new combinations in the book. Eretes occidentalis is also added. Hygrotus dissimilis (Gemminger & Harold, 1868). Add brackets and change the original citation to Hydroporus dissimilis. On page 826 Thermonectus nigrofasciatus and ornaticollis should be followed by Aubé, 1838 within brackets as the original binomina included Acilius. Hydroporus niger Say, 1823:102 instead of 103. Hydrocolus deflatus Fall, 1923:49 instead of 44. Anisomera recta LeConte, 1869:375, instead of 374. Agabus pallens Poppius, 1905:22 and Agabus discolor LeConte, 1852:204. As Liodessus fuscatus (Crotch, 1873) was first described as Hydroporus, it is preoccupied by Hydroporus fuscatus Stephens, 1828 (= H. planus (Fabricius, 1781)). If Crotch’s name cannot be conserved, a replacement name is needed. The authors note that Neoporus mixtus (LeConte, 1855) is the oldest name in the clypealis-complex. However, LeConte’s name is preoccupied by Hydroporus mixtus Steven, 1829. Neoporus blanchardi (Sherman, 1913) is given as a replacement name for Hydroporus vitiosus Sharp, 1882, nec LeConte, 1855. However, Sharp’s misidentification is not an available name. Consequently, Sherman’s name is no replacement name, but rather he described a new species with indication to the description given by Sharp. Likewise, Hydroporus appalachius Sherman, 1913, is no replacement name. My observation affects the treatment of type data. Sanfilippodytes kingii instead of kingi. Neoporus asidytus (Young, 1984) instead of asyidtus. Agabus erytropterus (Say, 1823) instead of erythropterus. In this case Say’s original spelling is to be regarded as correct. Copelatus haemorrhoidalis (Fabricius, 1787) instead of haemorroidalis. Two lectotype designations from the book are redundant: Hydroporus subtonsus LeConte, 1855. The following sentence from Fall (1923, N. Am. Hydroporus and Agaporus) is a valid lectotype designation: ‘LeConte’s specimens were from Lake Superior and Vermont, the former bearing the name label may be considered the type.’ Ilybius picipes (Kirby, 1837). The authors cite the lectotype designation of Persson (1985) as valid. However, this designation is predated by the one of Larson (1975:375): ‘Type - ♂’ in BMNH labelled as follows’. Agabus stagninus (Say, 1823): neotype designated by Larson & Wolfe (1998). It is impossible to directly restrict the type locality, without going via type designations. Among dytiscids this tradition is best seen in Zimmerman’s (1970) Laccophilus revision. One example from this work is L. fasciatus Aubé, 1838, of which the type locality is restricted to ‘Cuitlahuac, Vera Cruz, Mexico’, although originally including Mexico and the US. In my opinion this restriction of the type locality has no official status whatsoever, although cited without comment in the handbook. The type locality of Neoporus sulcipennis (Fall, 1917) is given as ‘not restricted’. In the original description, Fall cited several localities. However, by writing ‘Farmington, August 4, type ♂’; Randolph, 1,300 ft.; Sherman’ he effectively selected a holotype. The statement that Say (1823:154) did not state the type locality of his Hydroporus undulatus is confusing as the original description ends: “Found in a pond near Bowyer Creek, Upper Missouri. It is not uncommon in Pennsylvania.” The type locality of Agabus perplexus Sharp, 1882, is erroneously given as Vancouver Island. The lectotype selected by Larson (1997) referred to was actually from California. Following Ádám (1996, Folia Ent. Hung. 57:5–64), Guignot’s 1946 designation of Hyphydrus pubescens Gyllenhal as type species of Hydroporus Clairville is invalid. It is simply impossible that the nomen nudum pubescens Fröhlich included by Clairville (1806) could represent the species described by Gyllenhal two years later under the same name. Instead Ádám designated Dytiscus fusculus Schrank, 1781 (=H. planus (Fabricius, 1781)).

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.