New and Little Known Giant Earthworms from Madagascar (Oligochaeta: Kynotidae)

ABSTRACT During a survey of the soil macrofauna of Madagascar three giant earthworm species were collected in the eastern part of the island. One of them, Kynotus friderici Michaelsen, 1931, is a known species described as K. longus var. friderici Michaelsen, 1931 and elevated to species rank herein. The other two species, K. giganteus sp. n. and K. proboscideus sp. n., proved to be new to science. K. giganteus measures alive 1350–1400 mm in length, 20–25 mm in diameter; K. proboscideus alive is ca 500–600 mm long and 15–20 mm in diameter. All worms belong to the Malagasy endemic family Kynotidae.


INTRODUCTION
Earthworms constitute a major part of the soil macrofauna and play a paramount role in the soil processes; therefore they are regarded as soil ecosystem engineers (Jones et al. 1994, Decaëns et al. 2001. In spite of their importance, taxonomic research on earthworms, especially in Africa, is quite limited. Apart from some sporadic papers (e.g. Csuzdi 2005Csuzdi , 2010aZicsi 1996Zicsi , 1997, organised earthworm research is progressing only in South Africa (e.g. Plisko 2006Plisko , 2008Plisko , 2009Plisko , 2010, and papers cited therein). It is especially remarkable that no research has been carried out in Madagascar, although (Myres et al. 2000).
Previous data on the earthworms of Madagascar are quite scarce and usually have resulted from occasional collecting by different naturalists travelling on the island. The Geophagus darwinii was described by the German traveller Conrad Keller in 1887. In a summary of the earthworm fauna of the Malagasy Region, Michaelsen (1897) enumerated 18 species, including eight belonging to the native genus Kynotus. The last taxonomic paper on the Malagasy earthworms was published 80 years ago (Michaelsen 1931). Up to that time 32 species were recorded, in seven families, the Megascolecidae, Kynotidae (endemic family with a single genus), Acanthodrilidae, Eudrilidae, Ocneodrilidae, Octochaetidae and Glossoscolecidae. Among the species reported 19 (59 %) are autochthones and 13 (41 %) are introduced.
After 1931, no taxonomic study was carried out until April 2008, when a project entitled Fauna-M was launched. The main goals of this project were to explore the soil macrofauna of Madagascar in order to create a database and set up a museum collection for earthworms and other soil invertebrates (termites, coleopteran larvae). As et al. (2010) summarized the introduced earthworms of Madagascar, recording three new occurrences for the island. In this paper, we report on three giant earthworm species found during expeditions to different parts of Madagascar.

MATERIAL AND METHODS
All sampling was carried out on the eastern part of Madagascar. According to its vegetation, Madagascar is divided into two parts: the eastern part is generally covered by tropical forest and the western part by dry forest. The northern region around Antsiranana (Diego Suarez) is characterized by a tropical climate with two distinct seasons. The mean annual temperature is around 27°C with two maxima (March 30.75°C, December 28.1°C). The yearly precipitation is 900-1250 mm, with a seven-month dry forests. More to the south, along the eastern coast, is the region of Ambatondrazaka (the Mangoro-Alaotra hollow). In this region the climate is cooler, the yearly temperature is around 20-22°C and the precipitation is around 1100 mm. The original vegetation was medium-altitude dense forest, but these forests have largely disappeared and now only exist in isolated patches. In the south-eastern coastal part of Madagascar (the Atsimo-Atsinanana region) the annual mean temperature is ca 24°C and the precipitation is around 2000 mm. The original vegetation was characterized by rain forest but most of it has been destroyed by the traditional slash-and-burn agriculture ("tavy"), and the vegetation is now represented by secondary forests mixed with savannah (Donque 1972;Koechlin 1972).
ging and hand sorting were used to collect earthworms. We also applied the diluted formaldehyde method (Raw 1959) to extract earthworms when we found fresh casts; however, in the case of Kynotus giganteus the villagers did not permit us to use this method. Earthworms collected were killed in 50 % ethanol and preserved either in 96 % the Mixed Unit of Research in functional ecology and biogeochemistry of soils (UMR Eco&Sols), Montpellier, France and in the Hungarian Natural History Museum.
Specimens were deposited in the Hungarian Natural History Museum (HNHM) and in the Zoological Museum of the University of Antananarivo (ZMUA). TAXONOMY Family Kynotidae Jamieson, 1971 Diagnosis: Body cylindrical, dorsal pores absent. Clitellum annular or saddle-shaped (juvenile?), tubercula pubertatis absent. Male pores paired on 16, rarely on 15 (erroneous?) within copulatory pouches which when everted form clasper-like "appendages". Spermathecal pores multiple, praeclitellar frequently inconspicuous. Oesophageal gizzard 5, intestinal gizzard and calciferous glands absent. Supra-oesophageal vessel present. Tubular, prostate-like setal glands associated with copulatory pouches and the genital setae present. Excretory system holoic.  Michaelsen, 1931 was described possibly on a regenerated specimen (Michaelsen 1931: 533); this might be the reason for the much smaller length (330 mm) given. Michaelsen argued that friderici is very close to the typical form and there are differences only in the spermathecal system, which is entirely intraparietal in friderici but large and intracoelomic in longus. This is a difference with K. longus var. friderici is hereby elevated to species rank.
Habitat: The vegetation in the locality is formed by savannah and secondary forest with Ravenala madagascariensis very dominant.
Remarks: The new species exceeds in size all known Kynotus species. It is similar to K. darwini Keller, 1887 (= K. madagascariensis Michaelsen, 1891) but differs from the latter in its larger size, the position of the genital setae (13-15 in darwini, 14-16 in giganteus) and in the spermathecae (which are intracoelomic and sac-shaped in K. darwini, intramuscular and egg-shaped in K. giganteus sp. n.). Regarding its spermathecal apparatus the new species is similar to K. friderici Michaelsen, 1931; however, this species possesses only two spermathecal lines (14/15, 15/16) with 2-2 spermathecae on each side. A further difference can be found in the genital setae, which are claw-shaped in K. friderici and spoon-shaped in K. giganteus sp. n. It is remarkable that this giant worm possesses very small spermathecae completely embedded in the body wall, similar to several giant Ecuadorian earthworms such as Martiodrilus ischuros Zicsi, 1990, Martiodrilus crassus (Rosa, 1895 and Martiodrilus olivaceous James, 1990 (each ca 1000 mm long).
Kynotus proboscideus sp. n. prominent protrusions (Fig. 7). Segments: 1-3 simple, 4-13 clearly double ringed. Habitat: At all places the vegetation is formed by bush composed of invasive species (Phytolacca acinosa, Salvia coccinea, Ageratum conyzoides, Lantana camara, Ricinus communis, Sida rhombifolia), with many dead leaves on the soil and some other plant Remarks: The new species is similar to K. kelleri Michaelsen, 1892 in its size and colour, but clearly differs from it by the higher number of spermathecae (1-3 per side in kelleri, 6-9 in proboscideus) and the presence of two prominent probosces on the prostomium. There is only one other species with similar head structure, K. schistocephalus Michaelsen, 1897, but the new species is easy to distinguish because of its longer clitellum (21-40 in schistocephalus, 22-27, 48 in proboscideus) and the higher number of spermathecae (1-3 in schistocephalus, 6-9 in proboscideus).