Pontoscolex corethrurus ( Müller, 1856 )

Shen, Huei-Ping & Yeo, Darren C. J., 2005, Terrestrial Earthworms (Oligochaeta) From Singapore, Raffles Bulletin of Zoology 53 (1), pp. 13-33 : 15-16

Pontoscolex corethrurus ( Müller, 1856)

Lumbricus corethrurus Müller, 1856: 113 . Urochaeta hystrix Perrier, 1872: 142 . Urochaeta dubia Horst, 1885: 7 . Urochaeta corethrura – Rosa, 1889: 125. Pontoscolex arenicola – Beddard, 1892c: 126. Pontoscolex corethrurus – Beddard, 1892c: 127; Horst, 1893a: 328;

1893b: 51; Michaelsen, 1896: 197; 1897: 250; 1900: 425; 1922:

8; 1928: 9; 1932: 599; 1935: 101; Ude, 1905: 495; Stephenson,

1916: 349; 1930: 3; 1931: 283; 1932: 51; Gates, 1926b: 472;

1935: 93; 1937: 197; 1938: 221; 1949: 38; 1972: 54; Easton,

1984: 120. Pontoscolex hawaiensis – Beddard, 1896: 196.

Material examined. – 2 specimens ( ZRC), Bukit Timah , coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 5 Mar.2003 ; 57 specimens ( ZRC), Rifle Range Rd. opposite to Murnane Reservoir, coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 5 Mar.2003 ; 33 specimens ( ZRC), Upper Seletar Reservoir Park outside Nee Soon Rifle Range, coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 5 Mar.2003 ; 5 specimens ( ZRC), Kent Ridge Campus of National University of Singapore, coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 6 Mar.2003 ; 41 specimens ( ZRC), Sungei Buloh , coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 7 Mar.2003 ; 21 specimens ( ZRC), Turut Track , Kranji Wireless Station, coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 7 Mar.2003 ; 33 specimens ( ZRC), Singapore Botanic Gardens , coll. K. K. P. Lim & K. L. Yeo, 11 Mar.2003 ; 25 specimens (1 dissected)( ZRC), Nee Soon swamp forest along pipeline, coll. K. L. Yeo, K. K. P. Lim & David Nasir, 18 Mar.2003 ; 2 mature specimens ( ZRC), Rifle Range Rd. opposite to Murnane Reservoir, coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 25 Jun.2003 .

Description. – Body length (mature) 92-148 mm. Segments numbering 167-232. Prostomium lacking. Dorsal pores absent. Clitellum XIV, XV-XXII, length 3.98-6.73 mm, width 2.93-4.08 mm, saddle-shaped, setae present. Tubercula pubertatis longitudinal bands in XVIII-XXI, lateral to b. Head segments wider, secondary segmentation in postclitellar segments with an anterior non-setal annulet and a posterior setal annulet. Setae present from segment I, lumbricin (eight setae per segment), aa> bc, dd 0.5 body circumferences in the anterior portion of the body, gradually irregular and becoming quincunx towards the posterior end. Nephropores longitudinal, paired laterally in intersegmental furrows medial to c. Female pores, male pores and spermathecal pores not visible. Preserved specimens white, greyish brown around clitellum. Live worms without pigments, head portion pink, three pairs of bright yellow spots (calciferous glands) on lateral dorsum in front of clitellum when the head portion extended.

Septa 6/7-9/10 muscular, posteriorly directed. Gizzard in VI. Intestine enlarged from XV. Caecum absent. Three pairs of calciferous glands in VII-IX, oval shaped. Esophageal hearts in X-XI. Nephridia holoic, with a slender duct and a slightly enlarged distal end. Testes large in XV. Seminal vesicles one pair, follicular, flattened, extending from posterior portion of XV to XVII or anterior portion of XVIII. Prostate and accessory glands absent. Spermathecae three pairs in VII-IX, small, tubular, duct long, slender, ampulla 0.35-0.65 mm long, less than 0.2 mm in width, diverticulum absent.

Remarks. – Pontoscolex corethrurus is the most dominant earthworm in Singapore. A total of 219 worms, about 66.6% of the total specimens, were collected during the surveys in March and June 2003 (see Table 2). There was a record of 231 worms collected in Bukit Timah alone in February 1936 ( Gates, 1937). This exotic species is native to tropical America and the West Indies, and its pantropical distribution is due to successful colonization resulted from human transportation ( Gates, 1972, 1973). The species was about the commonest among worms brought to Kew Gardens according to Beddard ( Gates, 1972: 55). It was also a dominant earthworm in rubber plantations in Malaysia and Burma ( Gates, 1972). It is possible that the large scale introduction of Para Rubber in the late 19th century into Southeast Asia might have accelerated the expansion of its range. According to Horst (1893b), P. corethrurus was already present in Singapore in the early 1890s. This species occurs throughout the year ( Gates, 1926b, c).

FAMILY MICROCHAETIDAE