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Polydesmida: miscellaneous H+19 species 


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Asphalidesmus

Asphalidesmus

Asphalidesmus species are tiny H+19 polydesmidans found from the Wet Tropics in Queensland to far southern Tasmania. Adults are only 5-7 mm long, yellow-brown and very slow-moving. Small aggregations of Asphalidesmus adults can be found in wet rotting wood and accumulations of leaf litter, together with the all-white juveniles.

The three Tasmanian Asphalidesmus species are endemic. A. leae Silvestri, 1910 (image above) and A. parvus (Chamberlin, 1920) are very similar in appearance, but A. leae occurs only in the north and A. parvus only in the south (see maps). A. golovatchi (below) is a rare southern species which, like A. parvus, is sometimes found in caves. Adults of A. golovatchi are easily recognised by the raised ridges on the animal's back, but these are missing in juveniles and some cave populations. A. golovatchi can also be separated from the co-occurring A. parvus by checking the shape of the paranota: long and narrow in golovatchi, short and rounded in parvus. To be certain of species identification, examine the gonopods of mature males (illustrated below) under high magnification.


golovatchi

A. golovatchi (above). Note the two parallel ridges on the top of each ring.

A. leae and A. parvus are fairly common within their respective ranges and are ecologically resilient. A. leae is abundant in Pinus radiata plantations within its range, A. parvus is abundant in eucalypt regrowth arising from clearfall-and-burn silviculture, and I have collected both species in badly degraded forest fragments on farms. Neither species has been found at high elevations (above 1000 m).

Bonham et al. (2002), Chamberlin (1920), Mesibov (1997b, 1998b, 1999, 2002,2009), Silvestri (1910)


Tasmania mapgolovatchi

A. golovatchi
Mesibov, 2009

Tasmania mapleae

A. leae
Silvestri, 1910

Tasmania mapparvus

A. parvus
(Chamberlin, 1920)

 


gonopodsAsphalidesmus spp.

Gonopods of A. golovatchi (left), A. leae (middle) and A. parvus (right). Not to same scale 


Brachydesmus superus Latzel, 1884

Brachydesmus

This introduced species is 8-10 mm long and white or pale brown in colour. Brachydesmus superus is widely distributed in Europe and has been introduced into a number of other temperate areas. It has apparently been in Tasmania for many years: 'The Flat Brown Millipede, which ... frequently occurs in company with the White Millipede [Blaniulus guttulatus], is found all over the State' (Evans 1943: 83). Overseas, B. superus has been reported to attack some crops. In Tasmania, local populations of this species can be very large. It is the probably the third most abundant millipede in my backyard in Penguin (after Cylindroiulus brittanicus and Ommatoiulus moreleti). I have seen dense B. superus populations in garden mulch in parks around Tasmania.

Blower (1985), Evans (1943) 


Tasmania mapBrachydesmus     gonopodsBrachydesmus

Gonopods image shows (left) bottom view of gonopods in retracted position and (right) side view of raised right-hand gonopod (head is to left).


Dysmicodesmus jeekeli Mesibov, 2010

Dysmicodesmus

D. jeekeli male (top) and female (bottom).

Dysmicodesmus jeekeli is ca 8-9 mm long and seems to be rare. It resembles Tasmaniosoma species, and like them is found in eucalypt bark litter. However, the gonopods are very distinctive and are unusual in being fused together at the base.

Mesibov (2010b) 


Tasmania mapDysmicodesmus     gonopodsDysmicodesmus

Ginglymodesmus

Ginglymodesmus

Ginglymodesmus tasmanianus (left) and a close-up of the G. tasmanianus gonopods (right).

Males of Ginglymodesmus (formerly code-named 'genus E') are 5-6 mm long, uncommon and inconspicuous. Females have not yet been distinguished from other, very similar Polydesmida living in the same habitats. Adult males, however, are easily recognisable by their gonopods, which are long, slender and 'jointed' in the middle (arrow points to 'joint' in image above at right). The three known species of Ginglymodesmus can be identified by close examination of the gonopods (see below). G. sumac is so far known only from rainforest near Julius River and Lagunta Creek. G. penelopae and G. tasmanianus both occur in a range of forest types, and G. tasmanianus has also been found in coastal scrub.

Mesibov (2005c)


Tasmania mappenelopae

G. penelopae
Mesibov, 2005

Tasmania mapsumac

G. sumac
Mesibov, 2005

Tasmania maptasmanianus

G. tasmanianus
Mesibov, 2005

 


gonopodsGinglymodesmus spp.

Rear and side views of a gonopod of (A) G. tasmanianus, (B) G. penelopae and (C) G. sumac 


Setoisenoton pallidus Mesibov, 2010

Setoisenoton

This distinctive species, only 5 mm long, was formerly code-named 'genus F'. Setoisenoton pallidus is locally very abundant in rainforest leaf litter. Its range may extend into the Southwest. The strange genus name is Notonesiotes spelled backwards. Notonesiotes aucklandensis is a similar-looking dalodesmid found in the Auckland Islands, south of New Zealand. The two millipedes differ in having the sperm-carrying channel on the gonopod ending on opposite elements of the forked gonopod tip: anterior in Setoisienoton, posterior in Notonesiotes.

Mesibov (2010b) 


Tasmania mapSetoisenoton     gonopodsSetoisenoton

Undescribed H+19 miscellany

Welcome to the 'too hard' basket! In most Tasmanian habitats you can find tiny, pale, H+19 Polydesmida which are mature at 4-6 mm in length. Many have three transverse rows of tiny setae on the metatergites, and well-developed paranota with rounded posterior corners. Sorting on gonopod structure, I count more than 70 species in the State. All seem to be Dalodesmidae. If you find mature males that seem to fit in this miscellaneous grouping of Tasmanian Polydesmida, please email me with details. I won't be able to give you a scientific name, but for some species I can give you a code name (e.g. 'M31') and a map of previously known localities.