And Its Genera (Turbellaria, Tricladida, Paludicola) Robert W
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ANNOTATIONES ZOOLOCICAE JAPON ENSES Volume 54, No. 2 June l98l Published by the Zoological Society of Japan Redescription of Kenkia rhynchida, a Troglobitic Planarian from Oregon, and a Reconsideration of the Family Kenkiidae and its Genera (Turbellaria, Tricladida, Paludicola) With 7 Te-rt-ligures Masaharu Knw.lrnrsu Biological Loborator¡,, Fuji ll/onren's College, Sapporo, Hokkaido 001, Jupan and Robert W. Mtrcsell Depatlnrcilt oJ Biological Sc'iences, Texas Te<'h University, Lttl¡bock, Te.rts 79409, U.S.A. Asstn¡ct A poorly known North American cave species o1 the genus Kenkio (Trrrbellaria, Tricladida, Paludicola), Kenkia rhynchida HvvnN, 1937, is redesc¡ibed in the present paper. The status of the family Kenkiidae and its genera is also discussed. The genera Kenkía Hyul.N, 1937 (syn. Macrocotyla Hvvnr, 1956), and Sphallopla¿a o¡ B¡aucu¡vp, I 93 l, are redefined. Thus, the genus Kenkio now contains four species: K. rhynchida HvvrN, 1937; K. holJinasteri (HvvrN, 1954); K. glandulosa (HvrrlnN, 1956); and K. lewisi (KrNr, 1975). The genus Sphalloplanrt now contains about 20 species, most from the U.S.A. but two from Japan and one lrom South Korea. The purpose of this paper is to present a redescription of a rare and unusual cave-adapted planarian, one which prompts a re-examination of the paludicolan family Kenkiidae and its genera. In 1937, L. H. Hyvr¡,N described a remarkable cave-adapted triclad, Kenkia rltynchida, collected by C. L. Husss in 1934 in the waters of Malheur Cave in Oregon. ln this same paper (HvlrlN, 1937), she also created the genus Speophila for another assemblage of cave-adapted planarian, and she created the family Kenkiidae to contain these two genera as well as Sphølloplarc DE BEAUCHAMI, 1931, yet another genus of cave-adapted triclad. Small though it may be, this family of cave planarian, with its few genera and several species, has continued to perplex triclad researchers. One of the chief problems has been that Hyu¡r.r's original material on which the descripti on of Kenkia was based was poorly preserved, and not until recently has new, and well-fixed material become available to permit a much-needed restudy of K. rbtnchida. t25 126 M. K¡wnr'rrsu and R' W' Mlrcuell In 1972, MttcHst-L visited Malheur Cave and collected a single specimen of K. rhynchida, apparently the first collection of the planarian since it was lìrst found by Husns in 1934. Unfortunately, the animal disintegrated after being photo- graphed. shortly thereafter, however, Mrs. E. M. BeN¡olcr began a series of visits to Malheur Cave ielated to her studies ol pseudoscorpions, and she was fortunate enough to collect a few additional specimens of K' rhl'nchi¿la, some of which were serlt to us live and others fìxed in Bouin's fluid' M¡.rnnlnls AND METHoDS The material was prepared for study in K¡,w,,rx¡.rsu's laboratory. Specimens were fixed in Bouin's fluid and then translerred to 70% ethyl alcohol. They were then paraffin embedded and cut in selial sagittal section at 8 micrometers' Staining was with Delafield's hematoxylin and erythrosin. The numbers used in text to desig¡ate each sample aud specimen are those employed by K,rw.lra.rsu in his permanent recording system. Sp¡clEs DEscRlPrloN Order Tntcr¡.olP¡. Suborder P¡ru¡tcor¡. or PnosunsnLlA, Family Kenkiidae HvtltlN, 1937 Genus Kenkia Hvlt¡,N, 1937 KenkÍø rhynchìda Hvt'tlt'¡, 1937 The priucipal literature for this species is Hvunu, 1973 and l95l; KrNr 1972 and 1975; and K;rw¡r¡rsu. I978. External fecttures. Based on Hyrr,rrr's (1937) original description, this species has long been thought to be of unusual body form. HvtrlnN wrote as follows: ,,The preserved specimens were 2-4 mm. long, white arld devoid of eyes as usual in cavã planarians, and of the general shape ol a minute turtle' The rnain portion ofthe body is oval, strongly convex above, concave below; from the anterior end there projects a snout about 1/4-li5 the body length. ' ' Owing to the peculiar shape of the animal the pharynx and copulatory apparatus are forced into the slightty thickened posterior end and the postpharyngeal region is suppressed ' ' ' SÃe iough sketches sent to rne by Dr. Hus¡s show that the shape in life is practically unusual the same as in the preserved specimens." The preceding suggestions of an body shape were incorporated by Hvvtr.N (1937) into her definition of the gerrus below, Kenkict as follows: "Kenkiidae of abnormal body form, body oval, concave postpharyngeal region absent, pharynx and copulatory apparatus at the posterior end;..." The newly-collected specimens of K. rh),nchirla, however, demonstrate - Redescription of Kenkiu rh¡'n¡'¡r¡¿r, 127 nen of : found photo- ries ol he was orne of )clmens )y were Itaining text to in his )75; aud species lollows: ts usual portion :ior end peculiar Fig. L Kenkio rhynchida, eutire aninraf . - A, Living, dorsal (reproduced fronr Mrrc¡ren's nto the color slide, photogrant). B-H, Preserved, B, Dorsal (1243 a.): C, r,entral (1243 a); ssed... D, ventral (1243 b), note protruded snout arrd nrarginal adhesive zone; E, dorsal (1244 a); rctically F, ventral (1244a); G, dorsal (1244b), note protruded snout: H, ventral (1244 b), note phalynx ancl copr.tlatoly apparatus. unusual e genus clearly that the species is of normal planariid body forrn (Fig. lA). ln general o below, appearance, K. rh¡'nchida would seem to be quite sirnilar to Sphalloplana buchananÌ rosterior (Hvt'.taN, 1937) from caves in Kentucky (see HvnnN, 1937, frg. l6) and to S. pricei onstrate (HvvnN, 1937) from caves in Pennsylvania (see Hvva,N, 1937, 1ìgs. 20 and2l). I 128 M. K¡w¡rrrsu and R' W Mlrcur'll There can be no doubt now that the "abnormal" appearance of Hvu'rN's by specimens (see Hvv.Ltl , 1937, fig' l) resulted from strong contraction caused an improper fixative, perhaps formalin or alcohol. K,lwnrnrsu and Mtvnznrl (1972) have shown that planarians killed in some kinds of fixatives (Carnoy's fluid, ethanol, methanol, etc.) frèquently contract strongly and roll ventrally. The appear- ance of our Bouin's-fixed specimens is shown in Fig. I (B-H). In most specitnetts the dorsum became convex and the body margins rolled ventrally' Even so, a more One contracted or less normal planariid body form persisted in some (Fig. I D F). strongly resulting in an ovoid shape (Fig. I B and C). In one specimen, especially, the musculature of the atlhesive organ contracted in such a way as to give the ap- pearance of a snout (Figs. I G and H). If the ovoid shape of B and c in Fig. I is combined with the vent;lly-rolled margins of D in Fig. I and the "snout" of G and H in Fig. l, then an appearance is achieved that is alnrost idcntical to HYUnN's illustration (1937, fig. l). When quiescent, living specimens will also contract jn rather strongly and assume a more or less ovoid shape, not unlike that seen Fig. I (B unJ C). This contraction upon quiescence can be much more pronounced thán that described by Mlrcuelt (1974) lor the kenkiid Sphalloplana zeschi from Texas. Although appearing entirely white, K' t'h)'nchicla' in fact' is slightly pigmented' having microscopic, pale brownish spots on the dorsum, except for the head region' In preserved specimens, dorsal and ventral body margins were covered with a wide band of thin, brownish film, perhaps coagulated rhabdites' Inlernct! fealures. The dorsal epithelium is much thicker than the ventral' A well developed, wide margin al zone of many rhabdite-forming cells is conspicuous' The marginal adhesive glands are well developed, and their pores open ventrally near the body margin. The anatomy and histology of the adhesive organ have been described well by Hyv¡,t (1937). we can, however, supplement her discussion of the organ. Figure2 shows a sagittal view ofthe adhesive organ reconstructed from serial sagittal sections (Specimen No. 1244a). As Fig. I (B-H) indicates, the head, containing little else save the adhesive organ, assumes a more or less snout-like appearance upon fixation' It tapers anteriorly. The head is covered with the same type of epithelium as covers the remainder of the body except at its tip. Beneath the epithelium, there are three layers of subepithelial muscle fibers, a thin outer layer of longitudinal ones, a wider middle layer of circular ones, and a thin inner layer of longitudinal fibers. These muscle layers increase somewhat in thickness progressing posteriorly' The center of the head is occupied by a long, well developed, tubular adhesive organ (Figs. 2,3 and c). The orifice is lined with a glandular epithelium con- taining eosinophilous^ granules; this epithelium is also reflected onto the anterior tip oithe head surrounding the orifice. The anterior two-thirds of the organ is a rather wide canal and is irregularly lobed. This portion is lined by a highly glandular epithelium. Small cyanophilous rods are contained in the gland cells Redescription of Kenkict rhynchidct 29 ll\4i\N S sed by ( A,ZAKI s fluid, rppeaf- rm ctmens a more tracted ,eciallY, ocm the ap- eg rig. I is 'G and lm YMAN'S ontract seen in rounced icm / i from mented, regron. L a wide ventral. ¡icuous. ,entrally pco ocQ well by Figure 2 scm secttons ittle else s,m fixation. :lium as m, there gitudinal gitudinal ;teriorly. adhesive ooo um con- antertor organ ls a highly and cells fi bers ; ve, ventral epithelium. 130 M. K¡wrrnrsu and R. W. Mrrcx¿lr- along with many feebly eosinophilous granules.