Haemadipsa rjukjuana (Oka, 1910) Lai, Nakano & Chen, 2011

Lai, Yi-Te, Nakano, Takafumi & Chen, Jiun-Hong, 2011, Three species of land leeches from Taiwan, Haemadipsa rjukjuana comb. n., a new record for Haemadipsa picta Moore, and an updated description of Tritetrabdella taiwana (Oka), ZooKeys 139, pp. 1-22 : 4-8

Haemadipsa rjukjuana (Oka, 1910) Lai, Nakano & Chen, 2011 comb. n.

Haemadipsa japonica var. rjukjuana Oka, 1910. Annot. Zool. Jap. 7: 165-183

Haemadipsa zeylanica Takahashi, 1934. Rep. Jpn. Sci. Assoc. 10: 744-749

Haemadipsa zeylanica var. Moore, 1938. B. Raffles. Mus. 14: 64-80

Haemadipsa japonica var. rjukjuana Keegan & Toshioka, 1968. Biomed. Rep. 406 Med. Lab. No. 16. United States Army Medical Commend, Japan.

Haemadipsa zeylanica Wu, 1979. Quart. J. Taiwan Mus. 32: 193-207

Haemadipsa japonica Yang, 1996. Fauna Sinica, Annelida : Hirudinea. Science Press, Beijing, China.

Haemadipsa japonica var. ryukyuana Lai & Chen, 2005. Note Newsl. Wildlifers 9: 10-14

Haemadipsa japonica var. ryukyuana Lai et al., 2009. Zootaxa 2068: 27-46

Material examined.

L00062 & L00063 collected at 21st Sept. 2003 in the mountain in Yilan County.; L00064 collected at 16th Mar. 2002 in the Fushan Botanical Garden in Yilan County; L00101 collected at 23rd Apr. 2005 in the Fushan Botanical Garden in Yilan County; L00102 collected at 20th Jan. 2002 in the Fushan Botanical Garden in Yilan County; L00103 collected at 21st May 2005 in the Fushan Botanical Garden in Yilan County. L00026 collected at 20th Jan. 2002 in the Fushan Botanical Garden in Yilan County; L00027 collected at 19th Feb. 2002 in the Fushan Botanical Garden in Yilan County; L00098A (two specimens) collected at 16th Mar. 2009 in Mt. Otake, Akuseki-jima, Tokara Islands, Japan (29°27'56"N, 129°35'40"E); L00104 (three specimens) collected at 30th May 2005 in Wufong Town, Hsinchu County; L00105 collected at 16th Mar. 2002 in the Fushan Botanical Garden in Yilan County; L00106 collected at 20th Jan. 2002 in the Fushan Botanical Garden in Yilan County; L00107 collected at 27th Mar. 2004 in Hsoulin Town, Hualien County; and L00108 (two specimens) collected at 4th Aug. 2004 in the mountain in Yilan County.

Diagnosis.

This species can be recognized by the reddish, yellowish, or grayish brown dorsum that is blotched with elongated irregular black spots that are more or less connected, and the absence of a distinct median stripe (Fig. 1A). The nearly solid black venter with irregular margins clearly distinguishes this species from other land leech species (Fig. 1B).

External characters.

Body length 14-37 mm, maximum body width 2.5-5.3 mm, up to 10.5 mm in specimen filled with blood; anterior sucker diameter 1.2-2.4 mm, posterior sucker diameter 2.6-5.6 mm. Body elongated, slenderly cylindrical, with dorsum moderately depressed from the end of body to the head; venter more or less flat in relaxed specimens. Head of dorsal anterior sucker with usual sub-triangular outline (Fig. 1C), venter of lip with the broad median field marked by narrow, longitudinal ridges and a deep median fissure. Anterior sucker deep, wide, triangularly cupuliform with well-developed lateral buccal lobes and frill. Posterior sucker nearly circular, slightly longer than wide, diameter equal to or a little larger than maximum body width, with a definite anterior median prominence but no sharply hooked papilla. Auricles large, white or even translucent, trilobate with the middle lobe smallest, and conspicuous by their color in contrast with the body color.

Dorsum strongly tessellated, with three pairs of paramedian, intermediate and supramarginal lines of prominently elevated, translucent-tipped sensillae, and also scattered areas bearing smaller semi-transparent tipped sensillae on annuli in addition to the sensory one. Venter tessellated less and more smooth than dorsum, with white or translucent tipped sensillae in arrangement as those on the dorsum. Dorsum of posterior sucker tessellated, with five or six irregular circles of polygonal areas. Venter of posterior sucker with rays 71 or 72, with strongly flattened ridges terminated in little rounded lobes at the margin, and not penetrated into the relatively large central areolated region (Fig. 1D).

When alive, dorsum reddish, yellowish, or grayish brown, with scattered elongated, more or less connected lateral-posteriorly, irregular black spots. No distinct median stripe on the dorsum, but in some specimens the mid-dorsum less blotched by spots, sometimes similar to an indistinct pale mid-dorsal stripe (Fig. 1A). In lateral body, the region around the sensillae lacking in spots, sometimes similar as a broken pale lateral stripe. Venter uniform, solid black, with highly irregular lateral margins which usually connected with the irregular spots from the lateral body (Fig. 1B). Dorsum of posterior sucker the same but more or less brighter in color than dorsum, with scattered black spots (Fig. 1A). Venter of posterior sucker fawn, sometimes with few scattered dark spots (Fig. 1D).

Eyes five pairs, punctiform, arranged respectively at II (2nd annulus), III (3rd annulus), IV (4th annulus), V (5th annulus) and VI (8th annulus) in parabolic arc (Fig. 1C).

Ninety-seven annuli in total. I, II and III uniannulate, with irregular areas divided and with sensillae in the interocular region. IV uniannulate and the interocular region being divided into irregular areas with sensillae in two transverse rows. V biannulate dorsally ((a1a2)>a3) and uniannulate ventrally, with the a3 as the oral margin of the buccal ring and also the first perfectly definite annulus. VI triannulate with the three annuli approximately equal. VII triannulate with the three annuli of the same length. VIII quadrannulate (a1=a2=b5>b6). IX–XXII midbody somite and quinquannulate, with the five annuli of the same length and a2 projecting above the surface. XXIII quadrannulate (b1=b2=a2>a3). XXIV triannulate (a2>a1=a3). XXV biannulate ((a1a2)=a3), each annulus bearing the first and second auricular lobes at the margins. XXVI uniannulate and bearing the third auricular lobe at the margins. XXVII uniannulate. Anus a small longitudinal slit in XXVII (97th annulus). Gonoporesseparated by five annuli; male at XI b5/b6 (30th/31st annulus); female at XII b5/b6 (35th/36th annulus); both small transverse slits with pale and projecting margins strictly within furrows.

Internal characters.

Jaws three, crescent shaped, moderate size and highly prominent, with 78-80 teeth; one mid-dorsally, the other paired ones ventro-laterally, all in deep buccal chamber beyond the velum. Pharynx in VII–VIII, short, bulbous; with si x muscular ridges of spongy wall in which three continuous with the three jaws and the other three intermediately between the formers and surrounded by numerous unicellular salivary glands. Crop in VIII–XIX; with 12 pairs of caeca in VIII–XIX respectively; first nine pairs simple, unlobed, with the first two pairs small and indistinct; while the last pair of caeca in XIX elongated posteriorly to XXIII and lateral to intestine. Intestine in XIX–XXIII, no caeca, ventral to rectum in XXIII. Rectum short, wide, tapered towards anus.

Ten pairs of testisacs at XIII/ XIV–XXII /XXIII. Vas deferens enters epididymis in XII/XIII or XIII. Epididymis in XII/ XIII–XVI, in some cases even to XVIII; asymmetrical, one side of which more massive, located between atrium and vaginal sac, and usually covered the ovisacs and oviducts, while the other side extended posteriorly beyond the vaginal sac, elongated, less massive, and with major part covering on or being covered by the vaginal sac. Ejaculatory bulbs moderately large, elongated ellipsoid, lying at a much lower level by the sides of the atrium, connected by slender ejaculatory ducts with a sharp turning backwards into atrium in XI. Atrium large, rounded, conspicuous, rising well dorsad of the level of the nerve cord passing along in the right side. Prostate glands a layer of loosely compact. Ovisacs in XII, large, connected with long and curled common oviduct. Vaginal sac in XIV–XVI, cephalic end sometimes in XIII and the caudal end extended to XVII; elongated egg-shape, bubble-like with thin wall usually, connected with long and thick vaginal stalk extended anteriorly into female gonopore in XII (Fig. 1E).

Distribution.

Haemadipsa rjukjuana is only recorded in East and South East Asia, including the Indo-Chinese Peninsula, Malay Peninsula, Indonesia, Ryukyu Islands of Japan, and Taiwan. In Taiwan, we recorded this species during recent surveys in the moist forests of low- and middle-elevation mountains in Taipei, Hsinchu, Taichung, Nantou, Pingtung, Yilan, Hualien, and Taitung (Fig. 4).

Habitat.

Commonly inhabits the bottom of moist forests. It attaches onto leaf litter, grasses, and low bushes.

Host.

Primarily medium- or large-sized mammals, including humans.

Remarks.

Haemadipsa rjukjuana had previously been recorded with other synonyms, with variable taxonomic status that has rarely been clarified over the last century. Oka (1910) described a new land leech collected from Taiwan, and named it Haemadipsa japonica var. rjukjuana based on a brief inspection of the external color pattern. After two decades, Takahashi (1934) refered to all the land leeches in Taiwan as Haemadipsa zeylanica , which is a variable land leech species widely distributed in South and South-East Asia. Later, Moore (1938) recorded a land leech specimen from the Malay Peninsula, and illustrated both dorsal and ventral color patterns (Fig. 5, Plate IV in Moore 1938). The scattered spots on the dorsum and the solid black venter with irregular lateral margins indicate that it is very similar to the specimens inspected in this study; thus, it could tentatively be confirmed as Haemadipsa rjukjuana . However, Moore only recognized it as Haemadipsa zeylanica var., despite conspicuous differences in external color patterns, and only provided a few external descriptions, instead of a detailed inspection and investigation on its taxonomic status. In addition, Moore (1938) also mentioned that this variety resembled one of the land leeches illustrated, but not described, by Blanchard (1917). Thirty years later, Keegan et al. (1968) described this variety in more detail. They provided the first description of its reproductive system, and compared it against other varieties of Haemadipsa zeylanica . However, in addition to the external color patterns, they stated that there were no differences in the reproductive system between this variety and the subspecies Haemadipsa zeylanica japonica , i.e., the species Haemadipsa japonica in our study. At the end of the 1970s, Wu (1979) reviewed the previous studies of the leech fauna in Taiwan, and only referred to the land leech species of Haemadipsa zeylanica in his list. About two decades later, Yang (1996) mentioned that only Haemadipsa japonica was present in Taiwan, as the other common land leech species in Taiwan, Tritetrabdella taiwana , which had been described as a new combination by Sawyer (1986), had been mistakenly included. Finally, in the first decade of this century, Lai and his colleborators ( Lai and Chen 2005; Lai et al. 2009) stated the uncertain taxonomic status of this variety, and suggested the necessity of further studies. By comparing the morphology of Haemadipsa japonica var. rjukjuana specimens against Haemadipsa japonica , we found significant and consistent differences in both external and internal characteristics (Table 2). Therefore, its taxonomic status should be considered as a new species rather than subspecies or variety.