A Fresh-Water Archiannelid from the Colorado Rocky MountainsAuthor(s): Robert W. PennakSource: Transactions of the American Microscopical Society, Vol. 90, No. 3 (Jul., 1971), pp.372-375Published by: Wiley on behalf of American Microscopical SocietyStable URL: http://www.jstor.org/stable/3225199 .

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372 TRANS. AMER. MICROS. SOC., VOL. 90, NO. 3, JULY 1971 372 TRANS. AMER. MICROS. SOC., VOL. 90, NO. 3, JULY 1971

unfolded, lightly stained chorion, a darkly stained blastodisc, and a lightly stained yolk. A clear perivitelline space is plainly discernible just beneath the chorion. The entire picture is one of turgid, normal oocytes, as opposed to paraffin or gela- tin embedding which results in considerable shrinkage and distortion of the blasto- disc and yolk with a broken and folded chorion.

Eggs which were embedded using the above procedure, but lacking the glyc- erol treatment did not section very well (Fig. 2). These eggs were brittle, and often showed chorion breakage and distortion upon sectioning.

Eggs which were embedded using the above procedure but which were frozen slowly in the cryostat rather than in the rapid freezing lower temperatures (about -70 C) of the acetone-dry ice mixture showed artifacts resulting from the formation of large ice crystals (Fig. 3).

LITERATURE CITED

DAvIS, B. J. 1964. Disc electrophoresis, Part II. Ann. N.Y. Acad. Sci., 121: 404-427. HXGSTROM, B. E. & LONNING, S. 1968. Electron microscopic studies of unfertilized and fer-

tilized eggs from marine teleosts. Sarsia, 33: 73-80. HAYES, F. R. 1949. The growth, general chemistry, and temperature relations of salmonid

eggs. Quart. Rev. Biol., 24: 281-308. ORNSTEIN, L. 1964. Disc electrophoresis, Part I. Ann. N.Y. Acad. Sci., 121: 321-349. ZOTIN, A. I. 1958. The mechanism of hardening of the salmonid egg membrane after fertiliza-

tion or spontaneous activation. J. Embryol. Exptl. Morph., 6: 546-568.

A FRESH-WATER ARCHIANNELID FROM THE COLORADO ROCKY MOUNTAINS'

ROBERT W. PENNAK Division of Environmental Biology, University of Colorado,

Boulder, Colorado 80302

PENNAK, R. W. 1971. A fresh-water archiannelid from the Colorado Rocky Mountains. Trans. Amer. Micros. Soc., 90: 372-375. The archiannelid Troglochaetus beranecki is reported from the interstitial water of gravel substrates in Colorado moun- tain streams. It was previously known only from central Europe. Evidence is pre- sented to show that it is an archaic species with very slow geographical spread.

From phylogenetic and distributional standpoints, one of the most remarkable fresh-water invertebrates is the archiannelid Troglochaetus beranecki. It was first reported by Delachaux in 1921 from the underground waters of caverns in Switzer- land (Delachaux, 1921). More recent collections are from France (Delachaux, 1927; Hertzog, 1930), Hungary (Andrassy, 1956), Roumania (Plesa, 1957), Austria (Tilzer, 1968), and Germany (Ankell, 1943; Husmann, 1962; Noll, 1939; Noll & Stammer, 1953; Stammer, 1937; Wegelin, 1966).

1 Contribution No. 46, Limnology Laboratory, University of Colorado.

TRANS. AMER. MICROS. Soc., 90(3): 372-375. 1971.

unfolded, lightly stained chorion, a darkly stained blastodisc, and a lightly stained yolk. A clear perivitelline space is plainly discernible just beneath the chorion. The entire picture is one of turgid, normal oocytes, as opposed to paraffin or gela- tin embedding which results in considerable shrinkage and distortion of the blasto- disc and yolk with a broken and folded chorion.

Eggs which were embedded using the above procedure, but lacking the glyc- erol treatment did not section very well (Fig. 2). These eggs were brittle, and often showed chorion breakage and distortion upon sectioning.

Eggs which were embedded using the above procedure but which were frozen slowly in the cryostat rather than in the rapid freezing lower temperatures (about -70 C) of the acetone-dry ice mixture showed artifacts resulting from the formation of large ice crystals (Fig. 3).

LITERATURE CITED

DAvIS, B. J. 1964. Disc electrophoresis, Part II. Ann. N.Y. Acad. Sci., 121: 404-427. HXGSTROM, B. E. & LONNING, S. 1968. Electron microscopic studies of unfertilized and fer-

tilized eggs from marine teleosts. Sarsia, 33: 73-80. HAYES, F. R. 1949. The growth, general chemistry, and temperature relations of salmonid

eggs. Quart. Rev. Biol., 24: 281-308. ORNSTEIN, L. 1964. Disc electrophoresis, Part I. Ann. N.Y. Acad. Sci., 121: 321-349. ZOTIN, A. I. 1958. The mechanism of hardening of the salmonid egg membrane after fertiliza-

tion or spontaneous activation. J. Embryol. Exptl. Morph., 6: 546-568.

A FRESH-WATER ARCHIANNELID FROM THE COLORADO ROCKY MOUNTAINS'

ROBERT W. PENNAK Division of Environmental Biology, University of Colorado,

Boulder, Colorado 80302

PENNAK, R. W. 1971. A fresh-water archiannelid from the Colorado Rocky Mountains. Trans. Amer. Micros. Soc., 90: 372-375. The archiannelid Troglochaetus beranecki is reported from the interstitial water of gravel substrates in Colorado moun- tain streams. It was previously known only from central Europe. Evidence is pre- sented to show that it is an archaic species with very slow geographical spread.

From phylogenetic and distributional standpoints, one of the most remarkable fresh-water invertebrates is the archiannelid Troglochaetus beranecki. It was first reported by Delachaux in 1921 from the underground waters of caverns in Switzer- land (Delachaux, 1921). More recent collections are from France (Delachaux, 1927; Hertzog, 1930), Hungary (Andrassy, 1956), Roumania (Plesa, 1957), Austria (Tilzer, 1968), and Germany (Ankell, 1943; Husmann, 1962; Noll, 1939; Noll & Stammer, 1953; Stammer, 1937; Wegelin, 1966).

1 Contribution No. 46, Limnology Laboratory, University of Colorado.

TRANS. AMER. MICROS. Soc., 90(3): 372-375. 1971.

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SHORTER COMMUNICATIONS 373

FIG. 1. Troglochaetus beranecki, X 140.

Most of these investigators are convinced that the species is widely distributed in middle European drainage systems. It is found chiefly in the interstitial waters of coarse sand and gravel substrates of streams, especially in hyporheic and phreatic habitats at both low and high altitudes. It is also known from aquatic interstitial habitats in caves and underground waters.

In October 1969, the writer found what appears to be Troglochaetus beranecki in the interstitial water of gravel 20 cm below the substrate surface in the Middle St. Vrain Creek in Boulder County, Colorado, at an elevation of 2640 m. This is a typical Front Range rapid mountain stream. In October of 1970, this archi- annelid was also found in the gravel bottom of Half Moon Creek at an elevation of 3050 m near Leadville, Colorado. These collections form the first Western Hemisphere records for this species.

Morphologically, the Colorado specimens are indistinguishable from the de- scriptions and published sketches of T. beranecki (Fig. 1). Total length averages 630 /L. There are two blunt prostomial tentacles and seven pairs of parapodia. Each parapodium has a dorsal and a ventral fascicle of long, thin setae. The setae are easily broken off during field collecting. The cerebral ganglion occupies much of the prostomium. A pharynx and gut can usually be distinguished through the body wall. The digestive tract contains unidentifiable organic particles, but some

This content downloaded from 141.101.201.31 on Sat, 28 Jun 2014 13:53:01 PMAll use subject to JSTOR Terms and Conditions

374 TRANS. AMER. MICROS. SOC., VOL. 90, NO. 3, JULY 1971

diatom tests are found. Delachaux (1921) concluded that the species is at least partly carnivorous. No segmental septa can be seen.

Troglochaetus is related to several marine archiannelid genera in the Family Nerillidae such as Nerilla, Mesonerilla, and Nerillidium. Ax (1954) has described what is probably the most closely related genus, Thalassochaetus, from the littoral of the North Sea. He believes that Thalassochaetus and Troglochaetus had a common ancestor.

Since its marine ancestry seems unquestioned, Troglochaetus is another piece of evidence which emphasizes the importance of the marine-brackish-fresh- water "highway" into the psammon, subterranean, and phreatic zones of conti- nental land masses (Pennak, 1963a). The occurrence of T. beranecki in inland areas of both the Eastern and Western hemispheres, however, would imply that it is a very ancient or archaic species. Among the Nerillidae there are no special resting eggs or cysts that would facilitate rapid overland dispersal, and geographi- cal spread by means of interstitial and phreatic channels must be extremely slow, especially where migrations have been into high altitudes against phreatic and ground-water currents. Indeed, it is tempting to think of the genus as having originated before continental drift was well under way, and that it has been able to survive through glacial periods, continental uplift, and erosion because of its ecological role as a cold stenotherm in the security of subsurface waters. Tilzer (1968), however, believes that recent glaciation destroyed the interstitial sub- terranean forms in Europe, and that reimmigration from non-glaciated areas was possible because Troglochaetus is assumed to have a high migration ability! The writer (1963b), on the other hand, has shown that Front Range glaciers in Colo- rado receded only about 7000 years ago, and it would seem highly improbable for Troglochaetus to have migrated vertically in the magnitude of a thousand meters during this short postglacial interval, especially through small interstices in wet subsurface gravels. Indeed, the long parapodial setae of Troglochaetus beranecki should exert a considerable effect in retarding geographical spread. Such setae are anomalous since the great majority of interstitial metazoans, espe- cially Naididae (Oligochaeta) and Crustacea, are featured by short setae and reduced appendages (Delamare Deboutteville, 1960; Swedmark, 1964).

Logical evidence has recently been presented (Hermans, 1969) to show that the Archiannelida is not a primitive class of the phylum Annelida but rather an order of the class Polychaeta, with essentially all members of the order being more or less modified for the interstitial habitat. Troglochaetus beranecki is the only known archiannelid restricted to fresh waters. A problematical microannelid Rheomorpha neiswestnovae has been described from interstitial waters of fresh- water beaches in Russia, Poland, and Italy (Lastochkin, 1935; Moszynski, 1938; Ruttner-Kolisko, 1955); but, in my opinion, this species has oligochaete rather than archiannelid affinities.

If the class Polychaeta (excluding the order Archiannelida) is examined as a whole, there are only about 20 species (mostly Nereidae) that have completely adapted to the fresh waters of the world. None are interstitial and most are macro- scopic species with obvious polychaete morphology. All have close marine rela- tives, and except for the two or three species of Manayunkia, they are charac- teristically found within 40 km of a sea coast. Manayunkia is a lake genus of polychaetes known from Lake Baikal, the northeastern United States, and inland Alaska, Oregon, and California (Hazel, 1966; Holmquist, 1967; Pennak, 1953). In view of the great age and diversity of the class Polychaeta, it is remarkable that this group has had so little success in invading fresh waters.

I predict that Troglochaetus beranecki will be found in many other parts of North America when suitable habitats are carefully studied.

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SHORTER COMMUNICATIONS 375

LITERATURE CITED

ANDRASSY, I. 1956. Troglochaetus beranecki Delachaux, ein Reprasentant der fur die Fauna Ungarns neuen Tierklasse Archiannelida. Ann. Hist. Nat. Mus. Nat. Hungarici, Ser. Nov. 7: 371-375.

ANKELL, W. E. 1943. Bathynella, Troglochaetus und Fonticola bei Darmstadt. Zool. Anz., 142: 179-181.

Ax, P. 1954. Thalassochaetus palpifoliaceus nov. gen. nov. spec. (Archiannelida, Nerillidae), ein mariner Verwandter von Troglochaetus beranecki Delachaux. Zool. Anz., 153: 64-75.

DELACHAUX, T. 1921. Un Polychete d'eau douce cavernicole. Troglochaetus beranecki nov. gen. nov. spec. (Note prel.). Bull. Soc. Sci. Nat. Neuchdtel, 45: 3-11.

1927. La fauna des eaux souterraines du Jura. II. Troglochaetus beranecki Delach. Le Rameau de Sapin. J. Vulganisat. Sci. Nat., (II) 11: 18-20.

DELAMARE DEBOUTTEVILLE, C. 1960. Biologie des Eaux Souterraines Littorales et Conti-

nentales. Hermann, Paris. 740 pp. HAZEL, C. R. 1966. A note on the freshwater polychaete, Manayunkia speciosa Leidy, from

California and Oregon. Ohio J. Sci., 66: 533-535. HERMANS, C. 0. 1969. The systematic position of the Archiannelida. Syst. Zool., 18: 85-102. HERTZOG, L. 1930. Notes sur quelques Crustaces nouveaux pour la plaine d'Alsace (Bas-

Rhin). Bull. Assoc. Philom. Alsace Lorraine, 7: 355-364. HOLMQUIST, C. 1967. Manayunkia speciosa Leidy-a freshwater polychaete found in north-

ern Alaska. Hydrobiologia, 29: 297-304. HUSMANN, S. 1962. Okologische und verbreitungsgeschichte Studien iiber den Archianneliden

Troglochaetus beranecki Delachaux; Mitteilung iiber Neufunde aus den Grundwasser- stromen von Donau, Ybbs, Otz, Isar, Lahn, Ruhr, Niederrhein und Unterweser. Zool. Anz., 168: 312-325.

LASTOCHKIN, D. A. 1935. Two new river Aeolosomatidae (Oligochaeta limicola). Ann. Mag. Nat. Hist., 15: 636-645.

MOSZYNSKI, A. 1938. Aelosoma neisvestnovi Last. 1935-un interessant oligochete psam- mique, nouveau pour la faune Polonaise. Arch. Hydrobiol. Ichtyol., 11: 275-281.

NOLL, A. & STAMIMER, H. J. 1953. Die Grundwasserfauna des Untermaingebietes von Hanau bis Wiirzburg mit Einschluss des Spessarts. Mitt. Naturw. Ver. Aschaffenburg, N. F., 6: 1-77.

NOLL, W. 1939. Troglochaetus beranecki Delach. im Maintal. Ein neuer deutscher Fundort. Zool. Anz., 125: 267-268.

PENNAK, R. W. 1953. Fresh-Water Invertebrates of the United States. Ronald Press, New York. 769 pp.

1963a. Ecological affinities and origins of free-living acelomate fresh-water invertebrates. In Dougherty, E. C. ed., The Lower Metazoa. Comparative Biology and Phylogeny. Univ. Calif. Press, Berkeley, pp. 435-451.

1963b. Ecological and radiocarbon correlations in some Colorado mountain lake and bog deposits. Ecology, 44: 1-15.

PLESA, C. 1957. Un animal cavernicol nou pentru fauna republicii populare Romine: Troglo- chaetus beranecki Delachaux (Archiannelida). Comun. Acad. Repub. Popl. Romtne, 7: 1035-1039.

RUTTNER-KOLISKO, A. 1955. Rheomorpha neiswestnovae und Marinella flagellata, zwei phylogenetisch interessante Wurmtypen aus dem Siisswasserpsammon. Osterreich. Zool. Z., 6: 55-69.

STAMMER, H. J. 1937. Der Hohlenarchiannelide Troglochaetus beranecki in Schlesien. Zool. Anz., 118: 265-268.

SWEDMARK, B. 1964. The interstitial fauna of marine sand. Biol. Rev., 39: 1-42. TILZER, M. 1968. Zur Okologie und Besiedlung des hochalpinen hyporheischen Interstitials

im Arlberggebiet (Osterreich). Arch. Hydrobiol., 65: 253-308. WEGELIN, R. 1966. Beitrag zur Kenntnis der Grundwasserfauna des Saale-Elbe-Einzugsge-

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