Key to Australian Freshwater and Terrestrial Invertebrates

Phylum Arthropoda
Subphylum Myriapoda
Class Diplopoda
Order Siphonophorida

Common name: sucking millipedes

Overview

Members of the order Siphonophorida are thin, extremely elongated millipedes that resemble Polyzoniida millipedes by the presence of a semicircular cross-section (dorsally convex and ventrally flattened) and anteriorly pointed head, reduced sucking mouthparts, and short, stout antennae. They differ from polyzoniids by their lack of eyes. These pale yellow-brown coloured millipedes often possess a large number of body segments (180 to 190), but rarely achieve a length greater than 1 or 2 cm. The siphonophorid, Illacme plenipes, holds the current record for most legs in an extant arthropod (750 legs) and the most segments (192) in a millipede.

Distribution and diversity

The order Siphonophorida occurs in North, Central, and South America, Caribbean, South Africa and Southeast Asia, Australia and New Zealand. There are 116 species described worldwide and three species in Australia.

Life cycle

Little is known of the mating behaviour of sucking millipedes, but the male gonopods on trunk segment VII enable the transfer of sperm into the female gonopore. Females of some species lays eggs in groups of up to 60 or so in a chamber in soil or leaf letter, protecting them by covering them with their bodies. The young hatch from the egg with four pairs of legs. Body segments and legs are added at later moults until the full adult complement is attained.

Feeding

Sucking millipedes have small, triangular heads that contain modified mouthparts, which enable them to pierce algae and plants; the fluids are then sucked into the mouth with a strong pumping action exerted by powerful muscles.

Ecology

Sucking millipedes live in leaf litter, in soil or under logs in moist forested regions. They use their triangular heads to push into crevices in soil and logs.