Haemopis kingi, New Species (Annelida, Hirudinea)

Abstract

While collecting specimens for the writing of The Leeches of the Okoboji Region, Iowa Lakeside Laboratory, Lake Okoboji, Iowa, 1946 and 1947, a new species of leech belonging to the genus Haemopis was discovered. Morphological and anatomical features of the leech show it to be distinct from other species of Haemopis, H. marmoratis Say, H. lateralis Say, H. plumbeus Moore and H. grandis Verrill, our American representatives, and H. sanguisuga, a closely related European species. The new animal has been named Haemopis kingi.* Diagnosis.-Size medium, never large (mature specimens, well extended, about 60 x 8 to 90 x 12 mm; living, fully extended, about 90 x 5 to 130 x 8 mm); elongate, slender, general body form similar to other Haemopis, but with region posterior to clitellum equidistant in width; caudal sucker conspicuously large, neatly or as wide as body; jaws triradiate, small, semi-globular and with 9 to 14 distichodont type teeth with lobed bases imbedded in a basal membrane which is held in position by membranous plugs which fit into pits in grooves which run over the free surface of the jaws; ejaculatory bulbs very small, short, fusiform, slightly cresdentic; atrium slender, rather short, U-shaped; right ejaculatory bulb and epididymis usually displaced one somite anterior to left (the right in XII, left in XIII); vaginal bulb small, pyriform, bent or curved and of two distinct regions: ental portion dome-shaped, rigid, curved or bent, distal portion globular, flaccid. Dorsal ground color uniform brownish-green or olivae with typical markings of a series of black, median blotches which form a continuous, longitudinal stripe, and scattered black and yellowish-orange blotches; margins conspicuously mottled with yellowish-orange blotches forming broken longitudinal lines; ventrally darker, plumbeous and uniformn except for occasional yellowish-orange blotches. Description of type.-Form elongate, slender. Cephalic end gradually attenuated, terete from clitellum anterior to the head region, which is slightly widened and flattened. Exciept for the last 2 or 3 annuli which attenuate rather abruptly the body region from the clitellum posterior is equidistant in width, rounded dorsally and somewhat flattened ventrally (when the leech is swimming this region is much flattened, the margins becoming thin and flangelike). This is the widest region of the body except during mating time, then the posterior clitellar region may become obviously wider. The body is rather muscular, quite firm. Measurements, well extended, in mm: length 78, to male pore 18; widths, buccal 3, at male pore 8, maximum (nearly same from somites XI through XXV) 9, anus 4 (living leech, fully extended, about 110 x 6); depths at same points 1, 3, 2.5, 1.5. Head relatively large, rounded. Mouth large, circular. Lips broad and thick, with distinct lateral lobes; dorsally areolated, of lighter pigmentation and with numerous sensory papillae; ventrally areolated, with 6 or 7 longitudinal furrows which extend back into the mouth and with numerouis sensory papillae which continue back along the margins of somite V, thence as two rows across the buccal ring. Buccal ring with moderate lateral lobes. Eyes 5 pairs, pigment cups large. Pairs 1 and 2 on caudal edges of somites II and III, largest, very conspicuous, directed cephalo-laterad and tilted slightly dorsal; pair 3 on caudal edge of IV al .and pair 4 on caudal half of V al, about one-half size of 1 and 2, somewhat deeper but conspicuous, directed latero-caudal and tilted slightly dorsal; pair 5 on middle of VI a2, about same size as 3 and 4, most deeply imbeddied, hence somewhat inconspicuous, directed caudal, and tilted slightly dorsal. Inequality of annulation begins with somite VI as discussed under annulation. Clitellum distinct, thickened, firm and extending over 15 annuli (X b5 through XIII a2). Gonopores separated by 5 annuli; male in anterior 1/3 of XI b6, an obvious, puckered transverse slit including a rounded pore which be-