Scaptobdella horsti, BLANCHARD, 1897

SCAPTOBDELLA HORSTI BLANCHARD, 1897

( FIGS 12–14)

Scaptobdellahorsti Blanchard,1897b:97–99,fig.19,20.– Kaburaki, 1921: 709. – Harding, 1931: 221–222. – Sawyer, 1986: 697, 751.

Salifa horsti – Soós, 1966a: 399.

Diagnosis: Male gonopore in somite XI c11/c12, female gonopore slightly anterior to middle of somite XII c11, gonopores separated by 5 + 1/2 annuli. Pharyngopore and pharyngoporal duct present, dorsally in centre of somite XIV c12.

Lectotype designation: One syntype, RMNH.Hi.683 ( Fig. 12), collected from Sumatra, was chosen as the lectotype for S. horsti in this study, because only this specimen bears an obvious dorsal pharyngopore in somite XIV. The other syntypes collected from Borneo possessed neither such a secondary pore nor such a duct connecting to the digestive tract. The original description was also provided based mainly on the lectotype designated herein (# 58 in Blanchard, 1897b).

Lectotype: RMNH.Hi.683, dissected, collected from Padang (~ 0.8°S, ~ 100.4°E), Sumatra, Indonesia, through Sumatra Expedition 1877/79, detailed collection date unknown ( Fig. 12C, D). GoogleMaps

Paralectotypes: Two specimens collected from Kalimantan, Indonesia, through Büttikoffer’s Borneo expedition 1893/94; RMNH.Hi.2230, collected from Liang Koeboeng , Borneo (= Gunung [= Mt.] Liang Kubung; see G. buettikoferi ); and RMNH.Hi.2231, collected from Sintang (~ 0.051°S, ~ 111.48°E), Borneo. Although Blanchard (1897b) mentioned that two individuals had belonged to RMNH.Hi.2231 (# 60 in his paper), only GoogleMaps one specimen comprises RMNH.Hi.2231 at present; the other specimen may have been lost in the past (Joke Bleeker, personal communication) .

Description of lectotype: BL 144.4 mm, BW 14.4 mm ( Fig. 12A, B). Caudal sucker ventral, elliptic; CL 8.3 mm, CW 9.9 mm ( Figs 12B, 13F).

Annulation of somites I–VII comprising 1 6 annuli altogether ( Fig. 13A, B); 1st annulus completely merged with prostomium, then 2nd (peristomium) = 3rd = 4th <5th> 6th = 7th <8th = 9th> 10th> 11th <12th = 13th = 14th = 15th <16th; 8th and 9th annuli forming posterior margin of oral sucker. Accordingly, annulation of somites I–VII tentatively interpreted as follows ( Fig. 13A, B): somite I merged with prostomium; somite II (= peristomium) uniannulate; somite III and IV biannulate, (a1 + a2) = a3, and (a1 + a2)> a3, respectively; somite V triannulate, a1 = a2 = a3, a2 and a3 forming posterior margin of oral sucker; somite VI triannulate, a1> a2 <a3, a1 with slight dorsal furrow; somite VII quadrannulate, a1 = a2 = b5 <b6. Somite VIII quinquannulate, a1> a2 = b5> c11 = c12, a1 with slight furrow ( Fig. 13A, B). Somites IX–XXIV sexannulate; IX–XII, b1 <b2 <a2 = b5> c11 <c12, each of a2 and b5 of somite IX with slight lateral furrow on respective sides, each of b2–b5 of somite X with slight furrow, each of b2–c12 of each of somites XI and XII with slight furrow ( Fig. 13C); XIII, b1 <b2 (c3 = c4) = a2 (b3 = b4)> b5 (c9 = c10)> c11 (d21 = d22 dorsally) = c12 (d23 = d24 dorsally) ( Fig. 13C); XIV, b1 <b2 (c3 = c4) = a2 (b3 = b4) = b5 (c9 = c10)> c11 = c12, each of c11 and c12 with slight furrow ( Fig. 13D); XV, b1 <b2 = a2 = b5> c11 = c12, each of b2–c12 with slight furrow; XVI, b1 <b2 = a2 (b3 = b4) <b5 (c9 = c10)> c11 = c12, each of b1, c11, and c12 with slight dorsolateral to ventral furrow, b2 with slight furrow; XVII, b1 <b2 = a2 <b5 (c9 = c10)> c11> c12, b1 with slight ventrolateral to ventral furrow, each of b2, a2, c11, and c12 with slight furrow; XVIII, b1 <b2 = a2 <b5> c11 = c12, b1 with slight dorsolateral to ventrolateral furrow on respective sides, each of b2–c12 with slight furrow; XIX and XX, b1 <b2 = a2 <b5 (c9 = c10)> c11 = c12, b1 of each somite with slight lateral to ventral furrow, each of b2, a2, c11, and c12 of each somite with slight furrow; XXI, b1 <b2 (c3 = c4) = a2 (b3 = b4) <b5 (c9 = c10)> c11 = c12, b1 with slight furrow, each of c11 and c12 with dorsolateral to ventral furrow; XXII and XXIII, b1 <b2 = a2 <b5> c11 = c12, b1 of somite XXII with slight ventral furrow, each of b2–c12 of somite XII with slight furrow, b1 of somite XXIII with two slight ventral furrows, each of b2–b5 of somite XXIII with slight furrow, each of c11 and c12 with slight dorsal to lateral furrow; XXIV, b1 <b2 = a2 = b5 = c11 = c12, each of b2–c11 with slight furrow, c12 with slight dorsal to ventrolateral furrow ( Fig. 13E, F). Annulation of somites XXV– XXVII comprising 10 annuli altogether ( Fig. 13E, F); 118th <119th> 120th = 121st <122nd = 123rd> 124th = 125th = 126th = 127th; 122nd being last complete annulus on venter; anus between 121st and 122nd with six post-anal annuli. Accordingly, annulation of somites XXV–XXVII tentatively interpreted as follows ( Fig. 13E, F): somite XXV quadrannulate, b1 <b2> a2 = a3, each of b1 and b2 with slight ventral furrow, b2 with slight furrow, a3 with slight dorsal furrow; somite XXVI triannulate, a1 = a2> a3, a1 with slight dorsal furrow and being last complete annulus on venter; somite XXVII triannulate; anus at somite XXV/XXVI with six post-anal annuli.

Male gonopore in somite XI c11/c12 ( Fig. 13C). Female gonopore slightly posterior to middle of somite XII c11 ( Fig. 13C). Gonopores separated by 5 + 1/2 annuli ( Fig. 13C).

Anterior ganglionic mass in 12th annulus (somite VI a3). Ganglion VII in 14th and 15th annuli (somite VII a2 and b5). Ganglion VIII in a2 and b5. Ganglia IX–XI, of each somite, in a2 ( Fig. 14C). Ganglia XII and XIII, of each somite, in b2 and a2 ( Fig. 14C). Ganglia XIV and XV, of each somite, in a2 ( Fig. 14C). Ganglion XVI in b2 and a2 ( Fig. 14C). Ganglia XVII and XVIII, of each somite, in a2 ( Fig. 14C). Ganglion XIX in b2 and a2 ( Fig. 14C). Ganglion XX in a2. Ganglia XXI–XXIII, of each somite, in b2 and a2. Ganglion XXIV in a2. Ganglion XXV in b1. Ganglion XXVI coalescing with posterior ganglionic mass. Posterior ganglionic mass in 122nd and 123rd annuli (somite XXVI a1 and a2).

Eyes undetectable.

Nephridiopores in 17 pairs, one each situated ventrally at posterior margin of a1 of somite VIII ( Fig. 13B), at posterior margin of b2 of each somite in IX–XII ( Fig. 13C), at posterior margin of b2 (c4) of each somite in XIII and XIV ( Fig. 13C), at posterior margin of b2 of each somite in XV–XX, at posterior margin of b2 (c4) of somite XXI, and at posterior margin of b2 of each somite in XXII–XXIV ( Fig. 13F).

Pharynx ( Fig. 14A) reaching to somite XV b2. Pharyngopore dorsal, in centre of somite XIV c12 ( Fig. 13D). Pharyngoporal duct simple, straight, descending to pharynx terminal end, in somite XIV c12 ( Fig. 14B). Crop reaching to somite XXI a2 (b4)/b5 (c9); terminal end of crop forming weakly developed sphincter between crop and intestine, in somites XX–XXI a2 (b4)/b5 (c9). Intestine reaching to somite XXIV b1/b2.

Testisacs uncountable ( Fig. 14C); on right side, in somite XIX b1 to somite XXII c12; on left side, in somite XIX b1 to somite XXII b2. Paired sperm ducts coiled, narrowing at junction with atrial cornua, then running proximally toward atrial cornua ( Fig. 14C); right sperm duct in somite XI/XII to somite XVIII/XIX; left sperm duct in somite XI/XII to somite XVIII/XIX. Pair of atrial cornua conical, curved posterolaterally, in somite XI c11 and c12 ( Fig. 14C–F). Atrium globular, in somite XI c11 and c12 ( Fig. 14C–F).

One pair of ovisacs long, thin walled, slightly folded, mostly running dorsally on respective sperm ducts ( Fig. 14C, G); right ovisac in somite XII c11 to somite XVI a2 (b3/b4); left ovisac in somite XII c11 to somites XV/XVI; both ovisacs turned posterodistally in somite XIII b2 (c3 and c4); converging in somite XII c11.

Variation: BL 53.0– 58.2 mm, BW 4.3–4.4 mm, CL 2.5–3.2 mm, CW 2.7–3.2 mm. Somites VIII–XII quadrannulate, a1 = a2 = b5 = b6, or a1> a2 = b5 <b6. Somite XIII quinquannulate, a1 (b1 = b2)> a2 = b5> c11 = c12. Male gonopore in somite XI/XII or anterior margin of somite XII a1. Female gonopore slightly anterior to middle of somite XIII a1. Gonopores separated by 4 + 1/2 annuli. Neither pharyngopore and pharyngoporal duct nor gastropore and gastroporal duct present.