On the function of the ultimate legs of some Scolopendridae (Chilopoda, Scolopendromorpha)

Abstract

The function of the variously shaped ultimate legs of Scolopendridae is briefly reviewed. Their function in Scolopendra heros Girard, 1853, Scolopendra subspinipes Leach, 1815, Scolopendra morsitans (Linnaeus, 1758), Scolopendra galapagoensis Bollman, 1889, Scolopendra hainanum Kronmüller, 2012, Scolopendra spinosissima Kraepelin, 1903 Cormocephalus aurantiipes (Newport, 1844) and Ethmostigmus trigonopodus (Leach, 1817), in which they are least specialised has been investigated. Specimens were tapped with forceps on different parts of the trunk to simulate the attack of a predator. When tapped on the first third of the trunk (near the head), the centipedes attacked the forceps with their forcipules. When tapped on the last third or the ultimate legs, they adopted a warning position, raising the ultimate legs to display the ventral and medial prefemoral spines as well as the spined coxopleural processes. In some cases the centipedes attacked the forceps with the claws of the ultimate legs by chopping down on them after lifting the legs high into the warning position. When tapped in the mid part of the trunk, the centipedes curled sideways to reach the forceps with their forcipules and ultimate legs simultaneously. Scolopendra galapagoensis not only lifted the ultimate legs into the warning position but also the last 3-4 pairs of locomotory legs, presenting their distodorsal prefemoral spines. This resembles the warning posture of some spiders. In addition to their function in warning behaviour, defensive stabbing, ritualised meeting reactions and during courtship behaviour, the ultimate legs may in addition act as hooks and perhaps be involved in species recognition. No evidence was found that the ultimate legs are used to catch prey, nor of prey or predators being held between the prefemora.

The ultimate legs of Chilopoda (Myriapoda): a review on their morphological disparity and functional variability

“…to capture its prey using the ultimate legs. This observation was recently corroborated by Kronmüller & Lewis (2015) showing that individuals being touched at the rear third of their body using forceps, raised and lowered their ultimate legs, and even occasionally attacked the forceps using their ultimate legs. Moreover, although the ultimate legs are not likely used for propulsion, they may serve at least as an anchorage.…”

“…Despite the age of Verhoeff’s publication, his hypothesis and related terminology never received any greater deal of attention. In fact, most of the literature holds on to the conventional terminology of two tarsal podomeres ( Brölemann, 1930 ; Lewis, 2010 ; Edgecombe & Bonato, 2011 ; Kronmüller & Lewis, 2015 ). Moreover, ultimate legs of cryptopids feature another structural peculiarity: prominently toothed ridges on the ‘tibia’ and ‘tarsus 1’, and the ability to move both against each other in a penknife-like manner renders the hypothesis of a raptorial leg a reasonable assumption (see Figs.…”

“…Moreover, ultimate legs of cryptopids feature another structural peculiarity: prominently toothed ridges on the ‘tibia’ and ‘tarsus 1’, and the ability to move both against each other in a penknife-like manner renders the hypothesis of a raptorial leg a reasonable assumption (see Figs. 5D , 5E , 5H ; 7A and below), although this idea has been challenged by several authors ( Lawrence, 1953 ; Lewis, 2010 ; Kronmüller & Lewis, 2015 ).…”

“…Some reports on scolopendromorph species indicate that they use their thickened ultimate legs as claws or pincers, holding forceps, or even as a defensive weapon ( Verhoeff, 1902 ; Kaestner, 1963 ; Eason, 1964 ; Manton, 1965 ; Bücherl, 1971 ; Schileyko, 2009 ; Kronmüller, 2013 ; Kronmüller & Lewis, 2015 ). Bücherl (1971) observed Scolopendra sp.…”

“…Moreover, although the ultimate legs are not likely used for propulsion, they may serve at least as an anchorage. Several species of Scolopendra (e.g., S. subspinipes Leach, 1815, S. abnormis Lewis and Daszak, 1996 or S. gigantea Linnaeus, 1758) are able to use their ultimate legs to fasten themselves to any substrate suitable (fabric, rock, plants or a camera tripod; Carpenter & Gillingham, 1984 ; Kronmüller & Lewis, 2015 ), and swing their bodies quickly from side to side in order to seize prey with their remaining legs. The most impressive example is the bat-catching S. gigantea .…”