Kenneth Christiansen

The genus Sinella with special reference to Sinella s.s. (Collembola: Entomobryidae) of China

Abstract The genus Sinella is discussed and major changes in the taxonomy of the genus are made involving new criteria and a re-examination of old criteria. A key to all world species is given. This new system is applied to the members of the genus Sinella s.s. found in China. Ten new species of the subgenus Sinella s.s. are described: affluens, browni, fuyanensis, insolens, plebia, qufuensis, quinocula, sineocula, triocula, and trogla.

Suprageneric Classification of Collembola Entomobryomorpha

Abstract The suprageneric classification of the order Entomobryomorpha (families Isotomidae, Tomoceridae, Oncopoduridae, Actaletidae, Coenaletidae, Paronellidae, Entomobryidae, Microfalculidae, Oncobryidae, and Praentomobryidae) is examined and revised. The families are placed in four superfamilies: Isotomoidea; Coenaletoidea, new status; Tomoceroidea; and Entomobryoidea. One new subfamily, Capbryinae, and two new tribes, Nothobryini and Bessionellini, are proposed. Entomobryoidea is examined in more detail at the level of subfamilies and tribes. The characteristics used for this classification are discussed and a scheme is presented. The rationale for the divisions used is discussed.

Biogeography of Hawaiian Collembola: The simple principles and complex reality

Abstract We estimate that over 90% of Collembola species now living in the Hawaiian islands have been recorded, but the distribution of the fauna on individual islands is less well known. The relative number of species on the different large islands, except for Hawaii, is similar to that of most other groups of organisms. It appears that most species of Collembola could find suitable conditions on most islands; the subgenus Entomobryoides may be an exception. Endemicity appears to be related to age of the region, to habitat type, and perhaps to altitude. The Hawaiian fauna appears to have been recruited primarily from North America and temperate Asia, with tropical southeast Asia providing a smaller component; Western North America appears to be the main source for exemic species, and temperate Asia for the ancestors of endemic forms. Modes of immigration are uncertain, but ocean transport seems most likely for endemies of North American and Oriental origin, especially mobile members of the Entomobryidae ...

Review of North American Species of the Genus Onychiurus (Collembola: Onychiuridae), With a Description of Four New Species From Caves

ABSTRACT The history of the genus Onychiurus is discussed. Four new Onychiurus species are described from North American caves: steinmanni and nathanieli from Colorado, reluctoides from Indiana, and furcisetosus from Virginia. Onychiurus reluctus Christiansen, 1961 is redescribed. A key for all of the known North American species is provided.

Critique of the Article “Collembola (Springtails) (Arthropoda: Hexapoda: Entognatha) Found in Scrapings from Individuals Diagnosed with Delusory Parasitosis”

In a recently published paper, Altschuler et al. (2004) argued that Collembola (springtails) can cause “stinging/biting and/or crawling” sensations. The collembological community has been highly critical of this report, but has discussed this issue primarily among the members of this community. However, allegations that springtails cause various dermatological problems, severe itching, and related symptoms have made it into the widely read on-line encyclopedia Wikipedia (http://en.wikipedia.org/wiki/Delusory_parasitosis, accessed August 8, 2008: “People with delusional parasitosis are likely to ask for help not from psychiatrists but from dermatologists, pest control specialists, or entomologists.”). The medical community has firmly rejected the linkage of insects and widespread dermatitis (Berrios 1985, De Leon et al., 1982, Gupta & Voorhees 1990, Wykoff 1987). Janssens and Christiansen (2007) do acknowledge that an allergic reaction to Collembola tissue or integument on the part of some sensitive people is possible and might lead to the crawling-on-skin irritation symptoms. Various sources and publications, however, have gone much farther and have alleged that some springtails may parasitize humans. This allegation is entirely inconsistent with springtail biology, and no such phenomenon has ever been scientifically confirmed. (For a summary of the literature on this subject, see .) Springtails sometimes can be abundant indoors in damp places such as bathrooms and basements, and under such circumstances may be found on one’s person, but this is only accidental. Claims of persistent human skin infection by springtails may indicate a neurological problem, or else delusory parasitosis, a psychological not entomological problem. Berenbaum (2005) commented on the Altschuler et al. paper, suggesting that the report was based on pareidolia; that is, the researchers simply imagined that they saw springtail-like shapes in the images when there were no springtails actually present. In this paper, we more specifically and categorically refute the contention of Altschuler et al. (2004). Volume 119, Number 5, November and December 2008 537

A preliminary report on the Cretaceous Collembola

Presently, a single specimen of Collembola has been described from the Cretaceous period. The present work describes the results of examination of over 70 specimens from Canadian Cretaceous amber. 63 specimens could be identified generically and none of these belonged to extant genera. All could be placed in one or another of 7 undescribed genera. Most of the specimens belong to a single undescribed genus of the family Isotomidae. Also included are members of the families Sminthuridae s.l., Neanuridae s.l., and Tomoceridae, Reexamination of the type of Protentomobrya reaffirms the separate familial status. In addition one additional specimen of an undescribed genus cannot be placed in extant families.

Ceratophysella richardi sp. n. (Collembola: Hypogastruridae) from USA, with Synonymization of the Genus Mitchellania with Ceratophysella

Abstract Ceratophysella richardi sp. n. is described from South Carolina, USA. Unusual characteristics of a new species (post antennal organ with posterior lobes not surrounding accessory boss, macrochaetae p2 on thoracic terga II-III set nearly in line with setae p1, setae m2 on thoracic tergum II sometimes present, setae p1 and p2 on abdominal tergum IV microchaetae and macrochaetae, respectively, and all body sensilla long) are intermediate between two genera and led the authors to synonymize Mitchellania Wray, 1953 with Ceratophysella Börner, 1932.

Collembola: (Springtails, Snow Fleas)

Publisher Summary This chapter discusses collembola or springtails which comprise one of the most widespread and abundant groups of terrestrial arthropods. Collembola have three thoracic segments and six or fewer abdominal segments, including a telson consisting of a dorsal and two ventral valves surrounding the anus. There are typically four antennal segments, each with musculature. Collembola vary enormously in form and somewhat in internal anatomy, but all lack malpighian tubules and most have paired labial nephridia that empty into the ventral groove at the base of the labium. One universal and unique feature is the ventral tube or collophore–—an istally weakly paired projection from the first abdominal segment with membranous diversity of form equal to that seen in any other order of insects. Collembola rarely interact overtly with humans. There are no parasitic Collembola and they are not known to transmit any disease. Collembola play an important role in the development and maintenance of healthy soils, but this is not generally appreciated.

Bellisotoma, a new genus of Isotomidae from North America (Hexapoda, Collembola)

Abstract A new genus of Isotomidae, Bellisotoma gen. n., is described. The new genus is a member of the Proisotoma genus complex and is characterized by a combination of having a bidentate mucro with wide dorsal lamellae that join clearly before the end of mucronal axis without forming a tooth and one strong ventral rib with basal notch that articulates with dens; having abundant chaetotaxy on both faces of dens; and abundant tergal sensilla. Bellisotoma gen. n. shows a furcula adapted to a neustonic mode of life, and may be a Isotopenola-like derivative adapted to neustonic habitats. Subisotoma joycei Soto-Adames & Giordano, 2011 and Ballistura ewingi James, 1933 are transferred to the new genus.