The Southern Hemisphere cambaloid millipede genera are here assigned or re-assigned to the families Cambalidae Bollman, 1893 and Iulomorphidae Verhoeff, 1924. Tasmanocambala is erected for the three Tasmanian cambalids, T. greeni gen. n., sp. n. (type species), T. tasmanica sp. n. and T. taylori sp. n. The new genus is distinguished by a thin, transverse tab at the tip of the anterior gonopod telopodite with a comb of setae immediately behind the tab. The iulomorphid Talomius weldensis gen. n., sp. n. is described from a single site in Tasmania’s southern mountain district. The new species is unusual among the Australian Iulomorphidae in having a fully-developed, ambulatory leg 1 in the male, and small, compact gonopods.

Diplopoda , Spirostreptida , Cambalidae , Iulomorphidae , Tasmania, Australia

The classification of the cambaloid spirostreptidans has long been unsettled:

“Suborder Cambalidea. The systematics of this group are, and will for a long time remain, in a state of particular confusion...” (Hoffman 1980: 82).

“Throughout this century great confusion has reigned regarding the classification of the ‘Cambalida’...” (Jeekel 1985: 101)

“Having had very little experience with cambalidans, I am not in a position to resolve this chaos...” (Shelley 2003: 191).

“Confusion still reigns in the various classification databases available on the WWW, and the position of all the “cambalidan” families are chaotic...” (Korsós and Johns 2009: 2).

Especially confusing has been the systematics of the Australasian cambaloid genera, which have even been placed in different orders (Mauriès 1987). In his classification of the Diplopoda, Hoffman (1980) placed three of the Australasian cambaloid genera in Cambalidae Bollman, 1893 and the rest in Iulomorphidae Verhoeff, 1924, which he described as “an assemblage of incongruities” (Hoffman 1980: 84). The 10 Southern Hemisphere iulomorphid genera were “provisionally referred here pending revisionary studies” (Hoffman 1982: 699).

Jeekel (1985) accepted Hoffman’s grouping as a working classification, and drew a tentative distinction between Cambalidae and Iulomorphidae. In both families the anterior gonopods are thought to deliver sperm, but the posterior gonopods are better developed in Cambalidae. Twenty years later, after examining the eastern Australian cambaloids he had collected in 1980, Jeekel retained the two-family classification and offered another diagnostic character:

“The main character used for distinguishing the Cambalidae from the Iulomorphidae is the presence of a well developed flagellum in the anterior gonopods. It remains to be seen if this character is of sufficient importance to separate the two groups. In the family Julidae genera with and without a flagellum may be quite closely related.” (Jeekel 2006: 65)

Korsós and Read (2012) decided that presence/absence of a flagellum was not of sufficient importance, and placed all Southern Hemisphere cambaloid genera in Iulomorphidae:

“...we prefer here to consider all the following 15 genera in the family Iulomorphidae. The only diagnostic difference for separating Iulomorphidae from Cambalidae was the absence of a flagellum in the anterior gonopods (Jeekel 2006a) but this can be a homoplastic, convergent character state as has been shown for the family Julidae (Enghoff 1981, Read 1990). Given this situation, we think it is plausible to combine the very similar Southern Hemisphere (i.e. Gondwanan) elements into one family.” (Korsós and Read 2012: 44)

Since “Gondwanan” and “Southern Hemisphere (-dwelling)” are not synapomorphies, this action left Iulomorphidae sensu Korsós & Read, 2012 not diagnosable on morphology. I accepted Iulomorphidae sensu Korsós & Read, 2012 for Amastigogonus Brölemann, 1913, Atelomastix Attems, 1911 and Equestrigonus Mesibov, 2017 (Mesibov 2017a). However, like Jeekel I have examined two distinct groups of Australian cambaloids: flagella-bearing taxa with relatively well-developed posterior gonopods and non-flagella-bearing taxa with greatly reduced posterior gonopods. The two groups differ ecologically as well, at least in southeast mainland Australia and Tasmania. The first group is most abundant in leaf litter and is common in dry forest and woodland, while the second is mainly associated with rotting wood in higher rainfall areas.

The higher classification of Australasian cambaloids may be resolved in future with the inference of a molecular phylogeny of the group. In the meantime, although I do not wish to further confuse the already muddled classification of the cambaloids, I would like to formalise the distinction between the two Australasian cambaloid groups. I am therefore restoring the Southern Hemisphere genera to the families in which they were placed by Hoffman (1980), with the addition of new Australian genera as assigned by Jeekel (2006, 2009) and Mesibov (2017a), and with species numbers from MilliBase (http://www.millibase.org/; accessed 2 January 2019) amended following Korsós and Read (2012) and Mesibov (2017a, 2017b) as follows:

Southern Hemisphere genera of Cambalidae Bollman, 1893:

Apocoptogonus Jeekel, 2006 (2 spp; eastern Australia)

Dimerogonus Attems, 1903 (1 Australian sp; eastern Australia)

Eumastigogonus Chamberlin, 1920 (11 spp; New Zealand)

Euryischiogonus Jeekel, 2009 (1 sp; eastern Australia)

Proscelomerion Verhoeff, 1924 (1 sp; eastern Australia)

Stenischiogonus Jeekel, 2009 (1 sp; eastern Australia)

Zinagon Chamberlin, 1957 (1 sp; southern Chile)

Genera of Iulomorphidae Verhoeff, 1924:

Amastigogonus Brölemann, 1913 (11 spp; Tasmania)

Atelomastix Attems, 1911 (30 spp; western and eastern Australia, including Tasmania)

Dinocambala Attems, 1911 (1 sp; western Australia)

Equestrigonus Mesibov, 2017 (1 sp; Tasmania)

Iulomorpha Porat, 1872 (ca 18 spp; southern Africa; excluding the three Australian “Iulomorpha” of Silvestri (1897), which may be cambalids)

Merioproscelum Verhoeff, 1924 (1 sp; eastern Australia)

Podykipus Attems, 1911 (3 spp; western Australia)

Samichus Attems, 1911 (2 spp; western Australia)

Thaumaceratopus Verhoeff, 1924 (2 spp; eastern Australia)

Victoriocambala Verhoeff, 1944 (2 spp; eastern Australia)

Cambalidae as recognised here and by Hoffman (1980, 1982) and Jeekel (2006, 2009) is a temporary, place-holding taxon and may not be a natural group. It can be distinguished from Iulomorphidae within the Australasian cambaloids by the much greater development of the posterior gonopods and by the presence of a long, very slender flagellum arising medially near the base of the anterior gonopod coxa.

In this paper I describe a new genus and three new species of Cambalidae from Tasmania. I also describe an interesting new species of Tasmanian Iulomorphidae and erect for it a new genus.

All specimens are preserved in 80% ethanol in their respective repositories.

Photomicrographs were taken with a Canon EOS 1000D digital SLR camera mounted on a Nikon SMZ800 binocular dissecting microscope equipped with a beam splitter. Measurements were made to the nearest 0.1 mm with the same microscope using an eyepiece grid and a reference scale. Photomicrographs used in the figures are focus-stacked composites prepared with Zerene Stacker 1.04. Scanning electron microscope images were acquired digitally using an Hitachi SU-70; specimens were examined after air-drying and sputter-coating with a minimal layer of platinum, then removed from stubs and returned to alcohol. The gonopods of the iulomorphid holotype were temporarily mounted in 1:1 glycerine:water and imaged using an eyepiece video camera mounted on an Amscope binocular microscope. Preliminary drawings of the gonopods were traced from printed copies of images, and drawings were then edited by reference to the actual specimens. Images and drawings were prepared for publication using GIMP 2.8.

Maps were drawn with QGIS 2.4. Latitude/longitude figures in the text (all based on the WGS84 datum) are given in decimal degrees to four decimal places, together with a spatial uncertainty. In some cases, collecting site locations have been upgraded from UTM grid references (on original labels, with the AGD66 datum), based on advice from collectors and the latest digital mapping of Tasmania. The spatial uncertainty figure covers the likely error in the location upgrade as well as my estimate of the likely error in the original location. All specimen records referred to in the text are in Supplement 1.

I follow Enghoff et al. (1993) in counting trunk rings by excluding the telson and giving podous + apodous ring counts, e.g. “(55+1) rings”, and I give the upper limits of the count ranges I observed rather than count frequencies.

Abbreviations:

QVMAG Queen Victoria Museum and Art Gallery, Launceston, Australia

TMAG Tasmanian Museum and Art Gallery, Hobart, Australia

ZMUC Zoological Museum, Natural History Museum of Denmark, Copenhagen, Denmark

There are far fewer specimens of Cambalidae in Tasmanian museum collections than of Iulomorphidae. My field experience over 45 years in Tasmania is that this difference is not due to sampling bias, but reflects the patchy distribution of Cambalidae. Where they occur, however, Cambalidae are often abundant. This “abundant but patchy” distribution is also characteristic of procyliosomatid Sphaerotheriida in Tasmania. Hundreds of pill millipedes can be found in small patches of richly organic forest soil in some areas, while none are seen in apparently identical macro – and microhabitats nearby.

The patchiness of cambalids in Tasmania accords with what Jeekel (2006) observed on the Australian mainland: “During a collecting trip through New South Wales by the author and his wife between 27.X. and 12.XI.1980 only five sites out of 32 yielded representatives of the family. Since each sample consisted of a different species, it is obvious that Cambalidae are quite local in their occurrence. Possibly also their appearance in the upper layers of the soil is restricted to periods of favourable weather conditions. Under such conditions populations may be quite numerous” (Jeekel 2006, p. 65).

Jeekel found no Cambalidae in Victoria or Tasmania (Jeekel 2009, p. 83), but I have observed specimens of Victorian Cambalidae in Museums Victoria and have also collected cambalids in South Australia (specimens deposited in the South Australian Museum).

The almost complete lack of cambalid records in northeast Tasmania is curious, as the region has been intensively sampled for millipedes over many years and hundreds of iulomorphid Spirostreptida have been collected there (see fig. 7 in Mesibov (2017a)). Two, possibly introduced, cambalid species are known from Cuckoo Plantation, which is a long-established Pinus and Eucalyptus plantation near Scottsdale in northeast Tasmania (QVMAG specimen lots QVM:2017:23:0054 and QVM:2018:23:0003). These two species, one of which appears to be a Dimerogonus, may have been carried to Tasmania from mainland Australia on forestry equipment. I have not found additional specimens of either of these species in the Plantation or elsewhere in northeast Tasmania, despite careful recent searching. A third QVMAG specimen lot (QVM:2017:23:0016) contains a female and a juvenile of a possible cambalid from a logged forest area northeast of Goulds Country in the Northeast.

Talomius n. gen. is the fourth iulomorphid genus to be recognised in Tasmania. Like the two Tasmanian Atelomastix species, T. weldensis n. sp. may have a restricted distribution, but it also possible that the three spirostreptidans will be found to have substantial ranges when Tasmania’s southern and southwestern wilderness areas are carefully sampled for millipedes in future.

I thank Henrik Enghoff (ZMUC), David Maynard and Tammy Gordon (QVMAG) and Kirrily Moore (TMAG) for the loan of specimens and assistance with registrations, and Sandrin Feig (Central Science Laboratory, University of Tasmania) for operating the Hitachi SEM. I am also very grateful to reviewer Sergei Golovatch for helpful suggestions on improving the manuscript.