Pheretima darnleiensis ( Fletcher, 1886 )

Shen, Huei-Ping & Yeo, Darren C. J., 2005, Terrestrial Earthworms (Oligochaeta) From Singapore, Raffles Bulletin of Zoology 53 (1), pp. 13-33 : 26-27

Pheretima darnleiensis ( Fletcher, 1886)

Perichaeta cingulata – Vaillant, 1869: 4 (part). Megascolex indicus Horst, 1883: 186 (part). Perichaeta indica – Horst, 1885: 4; Beddard, 1886: 298. Perichaeta darnleiensis Fletcher, 1886: 966 . Perichaeta vaillanti Beddard, 1890: 66 . Perichaeta martensi Michaelsen, 1892: 242 ; 1896: 240; Horst,

1893a: 324. Perichaeta bosschae Horst, 1893a: 324 ; Michaelsen, 1896: 238. Perichaeta padasensis Beddard & Fedarb, 1895: 73 . Perichaeta eoa Rosa, 1896a: 528 ; 1896b: 609. Perichaeta floweri Benham, 1897: 217 . Perichaeta madelinae Benham, 1897: 219 . Perichaeta belli Rosa, 1898: 286 . Amyntas martensi – Michaelsen, 1899: 87. Amyntas cingulatus – Beddard, 1900a: 615; 1900b: 892. Amyntas padasensis – Beddard, 1900a: 624. Amyntas bosschae – Beddard, 1900a: 625. Pheretima belli – Michaelsen, 1900: 255. Pheretima bosschae – Michaelsen, 1900: 256. Pheretima darnleyensis – Michaelsen, 1900: 263. Pheretima floweri – Michaelsen, 1900: 267; Gates, 1934: 258. Pheretima indica – Michaelsen, 1900: 275 (part); 1922: 41; 1923:

2; 1932: 614; 1935: 108; Gates, 1935: 83; 1937: 193; 1940:

413; 1949: 26. Pheretima martensi – Michaelsen, 1900: 282. Pheretima padasensis typica – Michaelsen, 1900: 290. Pheretima vaillanti – Michaelsen, 1900: 311. Pheretima benguetensis Beddard, 1912: 183 . Pheretima kuchingensis Stephenson, 1916: 337 . Pheretima borneoensis Ude, 1925: 109 ; 1932: 131; Michaelsen,

1928: 55; 1934: 45. Pheretima indica (Horst) subsp. typica – Michaelsen, 1928: 41; Ude,

1932: 146. Pheretima indica (Horst) f. typica – Stephenson, 1930: 1; 1931:

273; 1932: 47. Amynthas indicus – Sims & Easton, 1972: 235. Pheretima darnleiensis – Sims & Easton, 1972: 260; Easton, 1982:

732; 1984: 119.

Material examined. – 1 mature (clitellate) specimen (dissected)( ZRC), Right bank near mouth of Sg. Khatib Bongsu, coll. H. H. Tan, 13 Feb.2003 ; 2 mature specimens ( ZRC), Bukit Timah, coll. Benjamin Lee, 5 Mar.2003 ; 7 mature and 1 immature specimens ( ZRC), Rifle Range Rd. opposite to Murnane Reservoir, coll. K. K. P. Lim, D. C. J. Yeo & K. L. Yeo, 5 Mar.2003 ; 2 mature specimens ( ZRC), Singapore Botanic Gardens , coll. K. K. P. Lim & K. L. Yeo, 11 Mar.2003 ; 4 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. – Length 159 mm, weight 1.99 g. Segments numbering 107. Prostomium with a large everted buccal cavity. First dorsal pore 12/13. Setal number 35 in VII, 44 in XX, 9 between male pores in XVIII. Clitellum XIV-XVI, 4.27 mm in length, 4.75 mm in width, setae absent, dorsal pores absent. Spermathecal pores four pairs in 5/6-8/9, ventro-lateral, small transverse slits in the segmental furrows. Female pore single, medio-ventral in XIV. Male apertures paired in XVIII, about 0.26 body circumferences ventrally apart, each transverse slit with crenated margin on a white, round porophore. Genital papillae absent in both preclitellar and postclitellar regions. Specimens brown with purplish iridescence, lighter coloured on ventrum and dark brown on clitellum.

Septa 5/6-7/8 and 10/11-13/14 thick, 8/9 membranous, 9/10 absent. Gizzard large in VIII-X. Intestine enlarged from XVII. Intestinal caeca paired in XXVII, each simple, slender, extending anteriorly to 23/24. Esophageal hearts XI-XIII. Spermathecae four pairs in VI-IX, small, ampulla oval, its upper part and junction with diverticulum covered by nephridia. Diverticulum with a slender stalk and an ovalshaped seminal chamber about 0.46 mm in length. Holandry: testis sacs small, paired in X and XI. Seminal vesicles paired in XI and XII, each small with a prominent dorsal lobe. Pseudovesicles paired in XIII. Prostate glands paired in XVIII, racemose, follicular, occupying two to three segments in XVII-XIX. Prostatic duct very short with terminal end enlarged into a bulb (copulatory chamber) in XVIII. Accessory glands absent.

Remarks. – Pheretima darnleiensis is a holandric and octothecal earthworm. It possesses copulatory chambers and has nephridia on spermathecal ducts. Numerous synonyms of P. darnleiensis have been erected ( Gates, 1935). Sims & Easton (1972: 264) considered both names cingulata and indica are invalid as they have been wrongly applied (Article 49, Int. Code zool. Nomencl.), and the species should carry the first available name in the synonymy, which is Perichaeta darnleiensis . They regarded both cingulata (part) ( Vaillant, 1869) and indica ( Horst, 1885) as synonyms of Pheretima darnleiensis ( Fletcher, 1886) under the genus Pheretima Kinberg, 1866 on page 239, but placed indica ( Horst, 1883) as a member of the diffringens ( = corticis ) species-group of the genus Amynthas Kinberg, 1866 on page 235. Easton (1981: 49) subsequently regarded indica ( Horst, 1883) as a synonym of Amynthas corticis ( Kinberg, 1866) . There was neither explanation on why indica ( Horst, 1883) is considered a synonym of A. corticis nor explanation on why cingulata and indica had been wrongly applied.

The original description of indica ( Horst, 1883: 186-189) is brief (not perfect), like most of the early specific descriptions in oligochaete taxonomy of the late 1800s. Nevertheless, it clearly mentions in the first sentence that “Cephalic lobe extending over two thirds of the length of the buccal segment, dilating at the anterior part”. This character is similar to the everted buccal cavity, a unique character illustrated for indica by Beddard (1890, Plate IV, Figs. 1-3 ). Simply based on this character, indica ( Horst, 1883) is certainly not synonymous to A. corticis as Easton (1981) suggested. However, the footnote in the original description of indica ( Horst, 1883) remarks that “The Perichaeta -specimen described in my paper ‘Niederl. Arch. f. Zool: Bd. IV’ belongs to this species”. “My paper” refers to the paper of Horst (1879), in which there is a detailed description and well-illustrated figures of an earthworm from Java without a name of the species, but obviously it is A. corticis . Chen (1935: 34-35) was the first one to point out this confusion, and clearly stated that P. indica consists of more than one species. Apparently, those from Sumatra (Alahan Pandjang, Silago, Soepajang) are P. indica , and that from Java is A. corticis . Horst (1885: 4-5, Plate I, Fig. 1a, 1b and 1c ) re-describes indica based on specimens from Sumatra, and attaches with figures (spermathecae, prostate gland and prostatic duct with male copulatory pouch) that have the legend of “ Perichaeta indica Horst ” on page 8. The muscular duct of prostate gland of indica in Horst (1883) might imply the male copulatory pouch of indica in Horst (1885). However, the name “ indica ” has been wrongly applied, because it denotes partly to the specimens of P. indica ( Horst, 1883, 1885) from Sumatra and partly to the specimen of A. corticis from Java ( Horst, 1879).

In the remarks of the original description of indica, Horst (1883: 189) also noted that “Probably some of the specimens of P. cingulata , examined by Vaillant, are identical with M. indicus ; however Vaillant, as stated by Perrier, having confounded different species under this name,….”. The same statement was made by Beddard (1890: 57). Beddard (1892c) examined the type specimens of P. cingulata (Schmarda) and redefined it as Megascolex cingulatus , a different species from P. darnleiensis . Beddard (1892c) also found that none of the species confounded by Vaillant are identical with Schmarda’s specimens. Obviously, the name cingulata is invalid, because it has been wrongly applied (Article 49, ICZN) as Sims & Easton (1972: 264) indicated.

Among other synonyms mentioned by Gates (1935), the specific name, Pheretima decipiens ( Beddard, 1912) , is not considered a synonym of P. darnleiensis in this study because of its inadequate description. Sims & Easton (1972: 239) placed decipiens within the planata species-group of the genus Metaphire .

In the description by Sims & Easton (1972: 262) of P. darnleiensis , the setal number is 12-35 in VII and 38-45 in XX, much lower than those in the original descriptions of P. darnleiensis (60-66 per segment) from Darnley Island, P. madelinae (56 in V and 66 in XX) from Borneo and P. belli (48 in XII and 60 in XXV) from the Philippines. Apparently, the re-description of P. darnleiensis by Sims & Easton (1972) did not match the original description by Fletcher (1886). In spite of the setal differences of the specimens mentioned above, their other characters are not distinguishable from P. darnleiensis .

Pheretima darnleiensis is widely distributed in Southeast Asia: Sumatra, Java, Borneo ( Horst, 1883, 1885, 1893a, b; Beddard & Fedarb, 1895; Rosa, 1896a; Benham, 1897; Michaelsen, 1899, 1922, 1928, 1932, 1934; Stephenson, 1916; Ude, 1925, 1932; Gates, 1940); North Celebes [=North Sulawesi]( Michaelsen, 1899); the Philippines ( Beddard, 1890, 1912; Rosa, 1898; Gates, 1935); and the Malay Peninsula ( Beddard, 1900b; Stephenson, 1931, 1932; Gates, 1935, 1937, 1949). It is also found on islands such as Mentawei ( Rosa, 1896b), Christmas Island ( Michaelsen, 1935; Gates, 1935), Molucca, Fiji ( Gates, 1935), Darnley Island in the Torres Straits ( Fletcher, 1886), New Caledonia ( Beddard, 1886), and the Hawaiian Archipelago ( Beddard, 1896). The numerous synonyms indicate the abundance and vast distribution of this species. The occurrence of geographical morphs or races might be possible as supported by the setal difference mentioned previously.

Figures

Fig. 1. Glyphidrilus gatesi, new species, holotype (46+ mm). A, right latero-ventral view of wings and genital papillae (gp); B, left lateral view of wings and genital papillae.

Fig.2.Glyphidrilus horsti Stephenson, 1930.Left latero-ventral view of wings and genital papillae (gp).

Fig. 3. Glyphidrilus singaporensis, new species. A, right lateroventral view of wings and genital papillae (gp) of holotype; B, left latero-ventral view of genital papillae of a 140-mm paratype; C, right latero-ventral view of wings and genital papillae of a 140-mm paratype; D, ventral view of wings and genital papillae of a 112- mm paratype; E, dorsal view of spermathecae of holotype.