Szalay, L

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New data on Tasmanian water-mites (Hycl1·achnellae) with a list of recorded species By DR. L. SZALAY B ndape.sl, Ht.mgal'y (WITH 4 TF<;XT FIGURES) Prof. Dr. V. Brehm has handed over for study, some water-mites he had received through Dr. A. G. Nicholls. For this I wish to express my thanks to Prof. Brehm. We are grateful to Dr. A. G. Nicholls who collected the material in Tasmania. These water-mites, 46 specimens altogether, are from 5 locali-ties. Among them 7 species and 5 genera were determined. These, together, with the localities, are given in the following list:-1. Big Lake Waterhouse, 12 IX. 1949. Litnnochccres (Cyclotht·ix) cuustmlica Ldbl., 5 3 3. Eylais Nichollsi n. sp., 1 9. Eylais Nichollsi var. fr-atm-rw n. var., 1 9. 2. Cleveland Lagoon, 14 IX. 1949. Hydroch·mna rnonticola (Piers.), 6 3 6, 6 9 SJ. H eterolim.nesia Lundblacli. n. sp., 1 3 . Unionicola (Pentatax) longiseta Walt., 1 ij. 3. Pond 1, Tunbridge, 14. IX. 1949. Limnochwres ( Cyclothrix) ct.ustntliw Ldb l., 2 3 6 , 1 9 . Eylais (Eylm:s) e::ctendens var. tasFrwnicn n. var., 1 9. 4. Lake Leake near Weir, 30. XI. 1949. Unionicola (Pentata.x) longiseta Walt., 5 3 3, 12 SJ ¥. 5. Little Waterhouse Lake, 1949. Unionicola (Pentatax) longiseta Walt., 1 6', 1 9. These, together with descriptions of new species and varieties, are set out in systematic order. 1. Linmochares (Cydothrix) australica Ldbl. The specimens examined are closely allied to those described by Lund-blad. (1947, p. 13-17, table III, fig. 8-10). Localities: 1 and 3. 74 NEW DATA ON TASMANIAN WATER-MITES 2. Eylais (Eylais) extendens var. tasmanica n. var. Female: This form seemR to be near to the species Eyluis (Eylais) extendens (0. F. Mull.) in the form of the maxillary organ, but differs from the principal species mainly in respect of the pharynx. The oval body is 3 mm. long and 2·5 mm. wide. Its colour was pro-bably red (all specimens preserved in alcohol). The width of the eye-plates is 320 fl, length of one eye-capsule is 213 0 , width 131 fl· The anterior margin of intercapsular bridge scarcely rises above the hair-pores, medially considerably sinuated. The capsules slightly sinuated laterally to the middle. The pores of the eye-capsules are very fine. (fig. la). The length of maxillary-organ from the anterior end of mandible to the posterior end overhanging the pharynx, 606 po, and from the anterior end of the mouth to the posterior processes 412 !'-- The width across the Lases of the palpi 327 fl. The mouth is comparatively small, more or less circular, length 131 fl, width 142 f.h· The chitinous ring beyond the mouth-plate is 180 flo long and 155 fL wide in external diameter. The posterior processes of the maxillary-organ are comparatively short, they curve slightly inward. The maxillary plate is marked with very fine, hardly· observable, reticulations nearly to the middle, and with very fine pores at the end. The length of the pharynx is 426 fl, it is slender backwardR, gradually broadening about up to the middle (172 0 ), from the middle to the last quarter nearly the same width, rounded upwardR at the end. The chitinous ring before the pharynx-end is slightly prominent. The Rurface of the pharynx is covered with fine small granules. (fig. lb). The lengths of the segmentR of the maxillary palpi meaRured in microns on the dorsal side are as follo1vs :-I. == -, II. = 164, III. = 170, IV. = 311, V. = 196. Each segment, see fig. 1c, is armed with spiniform setae among which are some pectinate setae. The last segment ends with G-7 short spines. The epimeres are mostly anastomosed, armed with reticulate chiti-nous l'idges, the epimeral-plates more or less branching off transversely and possessing very fine transverse connections. This mesh 1vork of chitinous ridgeR seems to be more thick than in the true species and so thick in places that the epimeral surface seems to be quite porous. No particulars can be given about the outer genital-organs because the abdomen skin is damaged. Locality: 3. 3. Eylais Nichollsi n. sp. This new species resembles the European Eylais (S.lJ11eylais) infundi-bulifera Koen. and E?;lais austmlica Ldbl. described from Tasmania. The resemblance is mainly in the eye-plates. The maxillary organs and the more or less chitinous structure of the epimera are different. Unfortun-ately it could not be decided whether it is a species of the genus Syneylais or Eylais, because only one female specimen was at my disposal. Female: The oval body is 3 mm. long, 2·5 mm. wide. The colour was probably red. The eye-plates are 323 0 wide, broader than in E. austmlica (264 p.). The eye-capsules are 196 0 long and 128 ;;. wide, like E. infundilmlifera, DR. L. SZALAY 75 they are broader behind than in the front. An obtuse, moderately devel-oped bridge-process exists. On the right and left of this projection a little depression is noticeable. The eye-bristles arise from the front inner-corner of the eye-plates (fig. 2a). The comparatively broad maxillary-organ extends from the anterior-end of the mandible up to the posterior end of the pharynx (622 1-'), from the anterior end of the mouth-plates to the posterior processes, 393 1-' long, and across the bases of the palpi, 377 1-' wide. The nearly circular mouth-plate is 131 1-' long and 139 1-' wide. The chitinous ring placed outside the mouth-plate is 155 !"' long and 172 1~ wide across its interior margin. The maxillary basal plate is richly reticulate and up to one half densely reticu-lated, so that the surface is covered with big pores at one end, and with dense fine pores at the other. The length of the pharynx is 409 1~, and the maximal width about the middle 213 /-'· The chitinous ring before the pharynx-end is very distinct in front. The surface of the pharynx is also covered with fine pores, though these pores are somewhat larger than the pores of the posterior half of the maxillary plate (fig. 2b) . The maxillary palpi are rather slender. Length of each segment on its extensor surface are as follows (in /h) ; I. = 164, II. = 204, III. = 180, IV. = 339, V. = 200. For the structure of the palpi and bristles of the segments see fig. 2c. There are about 6-7 terminal spines. The epimeres are generally like those of E. australica, supported by anastomosed chitinous ridges, mostly crossing the epimeron-plates. The intervals of the mesh-work seem to be r€latively narrower in the new form, as in Lundblad's photograph. (Lundblad 1947, A, table IV, fig. 12) of E. australica, so that the epimeral surface partly seems to be porous. The external genital organs in general are like those of E. oush·alica. Locality : 1. With the species described above, (E. Nichollsi) there was found at the same place another female E1;lnis-specimen which resembles very much this form. It is known that these El}lais-forms are very variable, in spite of these circumstances this specimen will not be identified as E. NichoUsi, but will be described as a variety of this form, as there seem to be differences in some characters (body-size, eye-organ, maxillary-organ). 4. Eylais-Nichollsi var. fraterna n. var. Female: Length of body 3 mm. width 2 mm. thus smaller than the principal species. Body form oval, colour was probably red. The eye-organs are 327 v wide. Eye-capsules 188 0 long and 147 1), ':vide. Eye-organs resemble those of the European Eylais (Syneylais) discreta. Koen. Bridge-process does not exist, instead in the middle of the bridge a small stud-like structure (muscle attachment) is noticeable, otherwise the anterior margin of the intercapsular bridge is nearly quite even. The hair-papillae rest on the edge of the eye-capsules (fig. 3a). The maxillary organ measures 598 1~. from the anterior end of the mandible up to the posterior end of pharynx, 409 fh from the anterior edge of the mouth-plate up to the posterior processes and 360 f.L in width across the bases of the palpi. The circular mouth-plate is 147 f1 in diameter. The chitinous ring outside the mouth-plate measures 180 fh in length and 196 v in :width across its internal diameter. The maxillary plate is thickly 76 NEW DATA ON TASMANIAN WATER-MITES covered with large pores up to half of its area, and is not so distinctly reticulated as in the principal species. The maxillary plate is covered at its end with fine pores. Pharynx is 409 p. long, largest pharynx-width is 221 p. behind the middle. The chitinous ring is prominent in front of the pharynx-end. The porosity of the pharynx is similar to that of the principal species (fig. 3b). On the extensor surface the segments of the maxillary palpi have the following lengths (in p.) : I. = 131, II. = 164, III. = 172, IV. = 295, V. = 180. For the bristles of the maxillary palpi see fig. 3c. The anastomosed ridged sculpture of the epimera is generally similar to that of the principal form, but the mesh-work seems to be looser in this variety. The external genital organs show the same structure as in the princi-pal form. Locality: 1. 5. Hydrodroma monticola (Piers). The collection contained specimens, which I classified previously as Hydrodroma monticola (Piers.), though these little animals do not resemble exactly the form described by Piersig from West Java. Firstly there are size differences. The body length of the male animal described by Piersig is 0·842 mm. and its width 0·800 mm., the male animal of this collection which is described below is about 1150 p. long and 1065 p. wide; and the female animal is about 1260 p. long and 1180 p. wide. The length of the exterior genital organ in the male is 262 p., and in the female 262 p.; The genital plates are about of the same width in both sexes. The outer sex-organ does not show striking differences. In the specimen in question, the subcutaneous posterior inner-process of the anterior epimera-group is visible. These processes are medially connected, and furthermore grown together. The position of the con-crescence is marked with a scarcely discernible line or groove. Thus it arises between both anterior epimera-groups as a bridge of which the anterior margin is medially protruding (sometimes also the posterior margin of the intercapsular bridge but this is much weaker) . The mandible of the male is (with claw) 344 p., that of the female 377 p. long. The claws are 65 p. and 73 p. respectively. The measurements of the segments of maxillary palpi are dorsally (in p.) :-Male Female I. 65 65 II. 82 90 III. 49. 57 IV. 213 232 v. 90 104 This form was recently recorded by Lundblad from different parts of Australia and he noted that the specimens examined by him resemble Hydrodromo monticola (Piers.) to such an extent that he did not describe them. It would be desirable to have a detailed description of Lundblad's specimens because the specimens from Tasmania seem to differ from the typical H. monticola (Piers.) in some respects. Locality: 2. 6. Heterolimnesia Lundbladi n. sp. This new form seems to be closely related to the species H eterolim-nesia tasmanica Ldbl. but some characteristics, especially the· structure of the penis-organ, do not permit it to be identified with this species. DR. L. SZALAY 77 Male: Body without prominent epimera 1016 0 , with accentuated epimera 1147 0 long and 852 0 wide. Body elliptical. The original colour of the little animal was not certain, but it was probably brownish-lilac. 1. With the distal lengthening Skin structureless. Mandible (with claw) 417 0 long. The claw is 106 0 (fig. 4a). The maxillary palpi are in P. II and P. III rather thick. P. II is especially strongly swollen. This segment has on its v.entral side a strong and thick peg set backwards. On P. IV there are about 6 very little and thin hairs (fig. 4b) set ventrodistally. The measurements of each segment are as follows (in tL) :-I. II. III. IV. V. Dorsal length of segment 32 155 115 196 53 Distal height of segment 64 131 82 32 12 The length of the four epimera groups are 655 0 . The epimera edges are noteworthy for their strong chitinous margin. Both first epimeras lie quite apart and free from each other, a connecting chitinous bridge is not apparent. The three pairs of hind-legs, with the exception of the posterior seg-ment of IV, bear swimming hairs and also short strong spinous bristles. Especially on the end segment there are long spiniform setae. The end segment of leg III is slightly curved and provided with three ventral spines. The claws possess a dorsal and ventral spike. The claws of leg III are only a little longer and thicker than those of the anterior legs. The outer genital plate is of reversed heart-shape and 311 0 long. It is laterally to the middle and on the posterior edge deeply incised. Of the four acefabular groups, the two anterior ones possess 7 and 6 genital acetabulae respectively and each of the two posterior ones 13 genital acetabular (fig. 4c). The genital opening is 131 0 long. The penis apparatus ends in two curved hooks in the same way as in H. tasmanica, otherwise it is differently built. (fig. 4d, s. also Lindblad 1947, p. 48, fig. 31D). Locality: 2. 7. Unionicola (Pentatax) longiseta Walt. Length 573 p, in the male from the anterior end of the first epimere to the end of the posterior processes of the fourth epimere, 655 0 in the female. It is to be noted that the specimens studied here are not typical forms, as there are some differences to be observed. For example, we find dorsally on the 5 segments of the anterior extremities some (2-3) bristles and hairs, ventrally and distally 1-2 delicate hairs and on the end of these segments sulcate ones, v~z., a large ventral one and a weaker one on the outer side. 'fhe bristling of the epimeres resembles that of Unionicola (Hexatax) annulata Ldbl. (Lundblad 1947, p. 63, fig. 40), in the rather long and fine hair pointing outwards. This hair is not far from the posterior margin of the fourth epimere and attached on the middle. The long hair and the posterior processes of the fourth epimere are readily seen on the specimen in question. In spite of these contrasts, the specimens are considered to be merely different forms of one and the same species, the differences most probably being due to variability. Localities: 2, 4 and 5. 78 NEW DATA ON TASMA!\IAN WATER-MITES A list of ·water-mites of Tasmania, on the basis of the data available to the author is as follows:-1. Hyclrachna ( RhaiJClohydrachna) opyn·o:x:hnnta Hal. South Esk River·, Long-ford. Other distribution: West Australia. Victoria. 2. Hydraclnw. (Nhabdohydruchna) lasnwnica Ldbl. South Esk River, Long-ford. 8. L,i.-,ru-uJchares (Ci;clothrix) uustralica Ldbl. Big- Lake, VVaterhouse, Pond 1, Tunbridge. Otber distribution: West Australia, New South Wales. 4. EylniB anstm/{ca Ldbl. The Lagoon, the outflow of the Great Lake. 5. Eylais (Eylais) conti.l)ua. Ldbl. South Esk River, Longford. Other distri-bution: Victoria. G. Eylw:s (liJylnis) extendens var. tasmanica. Szal. Pond 1. Tunb1·idgfo•. 7. Eylais Nichol/si Szal. Big Lake, Waterhouse. B. Eylwis N icholfsi var. Szal. Big Lake, Waterhouse. 9. D-iplodontus Ldbl. South Esk River, Longfmd. Other dis-tribution: West Aust1·alia, Vic.:toria. 10. Hyd·rodrm11a dcspiciens (0. F. Miill.). South Esk River·, Longford. Other distl·ibution: This little animal is a cosmopolitan form. lL Hyd-rotlnnna monticola (Piers.). Cleveland Lagoon. Other distribution: West Java, Victoria, New South Wales, South Australia. 12. O:.n.ts austmlicus var. Jneridianus Ldbl. The Lagoon, the outflow of Great Lake. Other distribution: Victoria. lil. Pla.bdlijJ·outipoda pectil!ata Ldbl. The Lagoon, the outflow of Great Lake. 14. Limnesia australica Ldbl. South Esk River, Longford. Other distribution: South Australia, Victoria, New South Wales. 15. Heterolinrnesia tasrna11ica Ldbl. Hobart. Other distribution: South Australia, Victoria, New South Wales. 16. Hcterolimnesia Lnndb/adi Szal. Cleveland Lagoon. 17. Au8tmliobates ·u·iolaceus Ldbl. South Esk River, Longford. 18. A,nstmliobates Linde1·i Ldbl. South Esk River, Longford. The Lag'oon, the outflow from the Gr·eat Lake. Other distribution: New South \Vales, South Australia. lfl. AnstmliobCifes longiprtlpis Ldbl. South Esk River, Longford. Other dis-tJ·ibution: New South Wales, Victoria. 20. A ustmliobcttes lon,qipnlpis var. m•inm· Ldbl. South Esk River, Longford. 21. Aspidiobate.s scnta.tus Ldbl. Pool near to St. Clair. 22. Unionicola ( Pentata:r) longiscta Walt. South Esk River, Longford, Cleve-land Lagoon, Lake Leake near; Weir, Little Waterhouse Lake. Other distribufion : New Caledonia, Victoria. 23. Unionicola (He:r·u.tru) u1inutissinw. Ldbl. South F:sk River, Longford. 24. Unionicola (He:rata:<:) aJ1mrlata Ldbl. South Esk Hiver, Longford. 25. Koeniken (Koenikea) wt.stroZ.icct Ldbl. South Esk River, Longford. Other distribution: Victoria. 26. Koenikea. (Koenikea) uerTucosa Ldbl. South Esk River, Longford. 27. Arrcnurus (TFuncatw·1rs) tasmctnic1w Ldbl. Pool at the Lake St. ClaiJ·. the outflow of Lake St. Clair. EXPLANATION OF FIGURES li'IG. 1.-Eylais ( Eylais) c;dendcns var. ta.snw.11.ica n. var. ¥. a = eye plates, b = maxillary organ, c ="· maxillary palpi. inner view. FIG. 2.-Ey/nis Vichollsi n. sp. ¥. a = eye plates, b = maxillary organ, c ,= maxillary palpi, inner view. FIG. 3.-liJylais Nichollsi var. fratenw n. var. 9. a ey(! plates, b = maxillary m-gan, c = maxillary palpi from the inner side. FIG. 4.-Hcte1'0limncsiu Lnndbladi n. sp. 3. a ~ mandible, b = maxillary palpi, c epime1·a and genital area, d = penis organ in ventral view. DH" L SZALAY 79 Fig. 2. 80 ~I':W DATA ON TAS.vlANTAN WATER-MITES BIBLIOGRAPHY HALIK, L, 1H4l.~-Beitrag zu1· Kenntnis der Wassermilbenfauna Australiens. Sbornik entom. odd. Zemskeho Museamv Praze, XIX, 210, 1941, p. 103-118. LUNDBLAD, 0., Hl47.-Zur Kenntnis australischer Wassermilben. Ark. f. Zoologi, 40A, 2, 1H47, p. 1-82. PmRsJG, R., 1906.--Uber Susswasse1·-Acarinen von Hinterindien, Sumatra, Java un<l den Sanwi<.:h-Inseln-Zoolog. Jahrb. Abt. f. Syst., XXIII, 190G. p. :321-388. VIETS, KARL, 193G.---·Wassermilben oder Hydraearins. in: Die Tierwelt Deutschlands, XXXI, 1936. Jena. VIETS, KURT, 194!!.-Beitrag zur K.enntnis von Eylais e:x:tendeus (0. F. Muller 177G). (Hydrachnellae, Aeari).-Veroff. Mus. Bremen, A1, 1949, p. 41-105. WALTJ<;R_. C., 1915.-Les Hydracariens de la Nouvelle-Caledonie. in: Sarasin et Roux: Nova Caledonia. Zoo!. II, ii, 7, 1915, sp. p. 101-104. 

New data on Tasmanian water-mites (Hydrachnellae) with a list of recorded species

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