A new species of the genus Allonychiurus from China (Collembola: Onychiuridae)

Abstract

The genus Allonychiurus Yoshii, 1995 is briefly introduced and a new Chinese species, Allonychiurus megasomus sp. nov., from Jiangsu Province, is described. The new species is diagnosed as having 32/133/33343 dorsal pso, 11/000/ 01110 ventral pso, 0/000/10000 ventral parapseudocelli (psx), 2/012/22222 dorsal sensilla, PAO consisting of 18–22 compound vesicles, Abd. IV with median setae a 0 and p 0 , Abd. V with m 0 , tibiotarsus with 11 setae in the distal whorl, unguiculus without basal lamella and ventral tube with 8+8 setae. It is easily separated from other known species in the genus by the combination of above characters. The status of the species in the genus is discussed.

New Palaearctic species of the tribe Thalassaphorurini Pomorski, 1998 (Collembola, Onychiuridae)

“…Most probably, this latter suggestion was dictated by its practical usefulness, as well as by the impossibility to unity the known species of all these “genera” into more or less natural groups, based only on our present knowledge. For instance, according to Sun et al (2009) only five of about two dozen known species of Allonychiurus completely correspond to the diagnoses as given by Yoshii (1995) and Weiner (1996). Later the generic diagnosis was amended by Sun et al (2011) to include some species showing a partly reduced tibiotarsal chaetotaxy and smooth sensillar clubs in AO .…”

“…We can only state that all three types of labium ( А , АС and АВС ) are known in Thalassaphorura (Sun et al 2010), with АС being the most common. In the genus Allonychiurus , two types ( AC and ABC ) are found among species of the volinensis- group (Fjellberg 1999, our data), while only the AC -type is known in two species of the flavescens- group (see Sun et al 2009, 2011). The A -type is observed in Spinonychiurus epaphius Kaprus’ & Tsalan, 2009 and, according to Pomorski and Sveenkova (2006), in the genus Detriturus .…”

“…The variant with two prelabral setae seems to be more common (see Table 1), but this character is still unknown in Sensillonychiurus eisi , Sensillonychiurus virginis Pomorski & Sveenkova, 2006 and Sensillonychiurus geminus . Such a slightly reduced number of labral setae is also typical of all Thalassaphorura known for this character, as well as of the volinensis -group of Allonychiurus , but not of the flavescens -group, at least some of which showing nine labral setae (Yoshii 1995; Sun et al 2009, 2011). This feature is completely unknown in Detriturus , Spinonychiurus , and Micronychiurus , whereas among Agraphorura the existing information concerns only Agraphorura calvoi Arbea, 2005, which has nine labral setae (a presumed basal set for Onychiurinae), and Agraphorura sangelensis Kaprus’ & Stebaeva, 2006, with two prelabral and seven labral setae (our data).…”

“…41). The same is probably characteristic of the flavescens -group of Allonychiurus (Sun et al 2009, 2011) although the authors believe that not e 2 but one of the b –setae is absent. A relatively long a 1–seta could be suggested as a possible apomorphy of the genus, but there is not enough information concerning the other groups of Thalassaphorurini for such an assertion.…”

Redefinition of the genus Allonychiurus Yoshii, 1995 (Collembola, Onychiuridae) with description of a new species from China

“…PAO with simple vesicles undoubtedly places this species in Thalassaphorura Bagnall, 1949 according to original description, to observation of Sun et al (2009) and to re-examination of type specimens.…”