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4-1972

Fessisentis, a of Acanthocephalans Parasitic in North American Poikilotherms

Brent B. Nickol University of Nebraska - Lincoln, [email protected]

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Nickol, Brent B., "Fessisentis, a Genus of Acanthocephalans Parasitic in North American Poikilotherms" (1972). Faculty Publications from the Harold W. Manter Laboratory of Parasitology. 359. https://digitalcommons.unl.edu/parasitologyfacpubs/359

This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications from the Harold W. Manter Laboratory of Parasitology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. THE JOURNAL OF PARASITOLOGY Vol. 58, No. 2, April 1972, p. 282-289

FESSISENTIS,A GENUS OF ACANTHOCEPHALANS PARASITICIN NORTH AMERICANPOIKILOTHERMS

Brent B. Nickol Departmentof Zoology, The Universityof Nebraska, Lincoln, Nebraska 68508

ABSTRACT: Thirteen of 16 Siren intermedia collected in Union County, Illinois, were infected with from two to 49 specimens of Fessisentis fessus Van Cleave, 1931. There are no previous reports of identified specimens of Acanthocephalafrom Siren. This is also the first report of F. fessus since the original de- scription and representsnew host and locality records. Old siren harbor more and larger specimens than do young siren. Intensity of infection and host age do not, however, relate to variability of other mor- phological features. Two paratypes, the original description, and specimens from siren form the basis for redescriptionof Fessisentis fessus. It is now realized that the trunk of females may be up to 52 mm long and unlike all other species of the genus it possesses a subterminal genital pore. It is also known that lemnisci of males seldom reach the anterior testis and that proboscis hooks may be in as many as 21 lon- gitudinal rows. Contraryto the original description, F. fessus possesses two retinacula. The proboscis re- ceptacle departs from usual acanthocephalanmorphology in consisting of 2 muscular layers of tubular bundles with contractile fibers at the periphery enclosing a central area of noncontractilecytoplasm. Fes- sisentis necturorumNickol, 1967, and F. vancleavei Haley and Bullock, 1953, also possess 2 retinaculaand have proboscisreceptacles identical in constructionto those of F. fessus. Fessisentis and Fessisentidae are redescribed to conform to this additional information. Acanthocephalus vancleavei Hughes and Moore, 1943, agrees with Fessisentis as redescribed with the exception of cement gland number. One male spec- imen was reported to have a cement gland number atypical of both Acanthocephalusand Fessisentis. It is felt that this deviation should not be emphasized to the point of obscuring unique features shared with species of Fessisentis. Because of transfer of this species to Fessisentis, a new name, F. friedi, is pro- posed for F. vancleavei Haley and Bullock, 1953. Richard Heard has collected Fessisentis necturorum near Athens, Georgia, from larval Ambystomaopacum. This represents additional knowledge of host and geographical distribution.

In 1931, Van Cleave described Fessisentis dwelling Eurycea tynerensis collected near fessus as a new species of Acanthocephalaand Tahlequah, . For reasons discussed named a new genus, Fessisentis, and a new below, this species is now considered a mem- family, Fessisentidae, to reflect its taxonomic ber of the genus Fessisentis. The only other position. He felt that the form of the proboscis report of A. vancleavei was by Malewitz receptacle(with a pouchlikethickening contain- (1956), who tentatively identified specimens ing severalprominent nuclei at the posteriorend from E. multiplacatacollected near Tahlequah, of the outer wall), form of the testes (filiform Oklahoma, as A. vancleavei. with indistinctboundaries and extendingat least In 1953, Haley and Bullock described a new three-fourthsthe length of the trunk),possession acanthocephalan, Fessisentis vancleavei, from of one retinaculum(rather than two), an unusual sunfish, Lepomis gibbosus, collected at Dur- number of cement glands (four), and proto- ham, . Bullock has since col- nephridial organs associated with the uterine lected F. vancleavei from other species of fish bell served as evidence of the distinctness of (see Materialssection), and Fried and Koplin the Fessisentidae. Van Cleave later recognized (1967) collected it from , Catos- that structures originally interpreted as proto- tomus commersoni, taken in Northampton nephridia are pockets of the selector apparatus County, Pennsylvania. (Haley and Bullock, 1953). F. fessus was de- Nickol (1967) described Fessisentis nectur- scribed from , Aplodinotus orum from Necturus beyeri collected near Fol- grunniens,collected at Money, Mississippi,and sum, . F. necturorumhas since been until the current paper there is no published collected from larval Ambystomaopacum (see record of additional collections. Materialssection). Hughes and Moore (1943) described Acan- Golvan (1969) expanded the Fessisentidae thocephalus vancleavei from neotenic, stream- to include all members of the superfamily Echinorhynchoideawith four cement glands, Receivedfor publication3 August1971. elongations of the "middle" egg membrane, 282 NICKOL-THEGENUS FESSISENTIS IN NORTHAMERICAN POIKILOTHERMS 283 and without trunk spines. This added four wise stated. Numerals in parentheses are means genera from freshwater fishes (Echinorhyn- unless otherwise noted. choides Achmerov and Dombrowskaja-Achme- Fessisentis fessus Van Cleave, 1931 rova, 1941; MegapriapusGolvan, Gracia-Rod- (Figs. 5-12) and Paracavisoma rigo, Diaz-Ungria, 1964; Fessisentis of the and Fukui fessus, type species genus, Kritscher,1957; Rhadinorhynchoides has not been since its and three from marine fishes reported original descrip- Morista, 1937), tion. of additional Van Neorhadino- Subsequent discovery spe- (Cavisoma, Cleave, 1931; cies of Fessisentis and additional information and Pseudocavi- rhynchoides Yamaguti, 1939; about F. have necessitated soma Golvan and and one fessus redescrip- Houin, 1964), genus tion. Since the is in Van with in redescription based, part, (Filisoma Cleave, 1928) species on collected from a host in a freshwater and marine fishes to the Fessisen- specimens species different class from the host and from a tidae. type different locality, comparison is first made be- The only published record of an acantho- tween specimens from Siren intermedia and the cephalan from siren to date was by Altig who recorded an unidentified original description. (1967), species Specimens of Fessisentis fessus from Siren from Siren intermedia collected near LaRue intermedia agree closely with the original de- Union Illinois. In Swamp, County, April 1970, scription of the species. Specimens from the 16 S. intermedia collected near the site re- new host and locality do, however, differ in ported by Altig were examined. Thirteen of several respects. Compared to the original de- these were infected with from two to 49 speci- scription which reports females from 20 to 30 mens of Fessisentis fessus. No other acantho- mm long, females from siren attain a greater cephalans were collected. Other amphibians length. Those from siren were up to 52 mm examined from the same area (five specimens long and averaged 35 mm long. Length of of Eurycea longicauda, six of E. lucifuga, and males from siren did not differ from the original three of Plethodon cinereus) were not parasi- description. Lemnisci were described as often the anterior testis tized by acanthocephalans. Although Altig's reaching (Van Cleave, 1931), but in an accompanying did not specimens were not available for study, it figure they reach that far posteriorly. Only one specimen seems likely that they also were F. fessus. from siren possessed lemnisci which reached the anterior testis. MATERIALS Specimens from siren agreed with the in of This is based on the original description length pseu- study followingspecimens. docoelom male Acanthocephalusvancleavei: 1 paratypebearing occupied by reproductive sys- USNMaccession number 36872. Fessisentisfessus: tem and in having lemnisci more than twice 2 paratypes(1 female and 1 male) from Aplo- the length of the proboscis receptacle. F. fes- dinotusgrunniens collected at Money,Mississippi, sus from siren also with the de- and Van agreed original bearing Cleave's accession numbers in to number of 2256.26 and 2264.6; 138 (81 females,57 males) scription regard proboscis specimenscollected in UnionCounty, Illinois, from hooks in each longitudinal row and in the size Siren intermedia;11 (7 females,4 males) speci- of these hooks. The original description re- mens collectedby Mr. AndrewFriedrichs, South- 12 to 16 but easternLouisiana from S. ported longitudinal rows, speci- University, intermedia mens from taken at Manchac,Louisiana. F. necturorum:75 siren possessed 15 to 21 rows. Males (44 females,31 males) specimensused by Nickol averaged 17 rows and females 19. Haley and (1967) in the species description;16 (9 females, Bullock (1953) remeasured the proboscides 7 collectedfrom males) specimens larvalAmbys- of six F. and toma opacumtaken at Sandy Creeknear Athens, fessus paratypes reported lengths Georgia, by Mr. Richard Heard, Universityof from 315 to 325 in females and 225 to 250 in GeorgiaMarine Institute, Sapelo Island. F. van- males. Proboscis lengths of females from siren cleavei: 10 4 col- (6 females, males) specimens with the emended but those of lected from Anguilla bostoniensis, Fundulus hetero- agreed length, clitus, and Lepomis gibbosus taken at Newington, males were slightly larger, averaging 268. New Hampshire,and Esox americanus(collection Specimens from siren with the all Dr. Wilbur agreed original locality unavailable), suppliedby with L. Bullock,University of New Hampshire. description respect to body shape and All measurementsare in micronsunless other- egg dimensions. 284 THE JOURNAL OF PARASITOLOGY,VOL. 58, NO. 2, APRIL1972

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I NICKOL-THE GENUS FESSISENTISIN NORTH AMERICANPOIKILOTHERMS 285

The following redescription of Fessisentis about 130 long and 60 wide. Two retinacula leave fessus is based on the original description by posterior end of receptacle sac and insert on trunk wall. Proboscis invertor muscles wall of Van Cleave emended mea- penetrate (1931), proboscis receptacle dorsally at posterior end as a pair of surements of Haley and Bullock (1953), and closely associated, fragile retractors. Testes fili- specimens, including paratypes, mentioned in form, in tandem, often with indistinct boundaries; the Materials section of this paper. 2.5 to 11.2 mm (4.8) long and 160 to 290 (247) wide. Testes vary greatly in size and are equal, subequal, or single. Regardless of combination, Description total length of male reproductive system 12 to 15 Body elongate; mature males 10 to 25 mm (19) mm, occupying 65 to 80% of trunk length. Testes long, gravid females 20 to 52 mm (35) long. followed by 4 oval to claviform cement glands. Trunk devoid of spines; males average 0.8 mm Saefftigen's pouch between pairs of cement glands. and females 1.1 mm wide at widest point, usually Cement glands and Saefftigen's pouch greatly in posterior third of trunk. Females frequently variable in size. Female reproductive system, from dilated at posterior extremity. Proboscis clavate anterior edge of uterine bell to genital pore, occu- and with a length of 225 to 307 in males and 302 pies 3.2 to 4.4% (3.9) of trunk length. Uterine to 356 in females; maximum diameter 120 to 168 bell 168 to 336 (272) long and 130 to 225 (171) in males, 163 to 240 in females; armed with 12 to wide. Two large pockets on dorsal wall of bell. 21 longitudinal rows of 6 to 8 hooks each. Sexual Genital pore terminal to subterminal, usually ex- dimorphism in proboscis armature undescribed for tremely subterminal. Eggs elongate with 4 mem- specimens from fish. In specimens from amphib- branes, fertilization membrane with polar elonga- ians, males with 15 to 18 (17) longitudinal rows tions, but lacking knobs. Eggs measured through and females with 16 to 21 (19) rows. Both sexes body wall of fixed females 72 to 103 (93) long with 6 to 8 (7) hooks in each row. Hooks in and 6 to 14 (12) wide; living eggs in host feces each longitudinal row of two obviously different 111 to 124 (114) long and 14 to 19 (16) wide. sizes, usually in combinations of 4 large apical Type host: Aplodinotus grunniens. hooks and 3 small, spinelike proximal hooks, or 3 Additional host: Siren intermedia. large and 4 small hooks. Large hooks 41 to 60 Type locality: Money, Mississippi. (46) long and about 14 thick at junction of thorn Additional localities: Manchac, Tangipahoa and root, root prominent; small hooks 12 to 32 Parish, Louisiana; LaRue Swamp, Union County, (23) long and about 6 thick, root reduced. Neck Illinois. 112 to 154 (127) long and 149 to 240 (190) wide. Lemnisci nearly always equal in length; usually Remarks not lobed; more than twice, and often more than Fessisentis is 5 times, length of proboscis receptacle sac; 2.0 to fessus more widely distributed 3.8 mm (2.9) long in males, only occasionally in the southern drainage of the Mississippi level of anterior reaching testis; 2.9 to 5.1 mm River than previously realized. The frequency in females. sac (3.8) long Receptacle muscular with which siren are the size and variable in 418 to 912 in infected, large highly length, (596) and both sexes. Receptacle double-walled with outer attained, production of eggs indicate that wall thickened posteriorly to form a pouchlike area Siren intermedia is a favorable host for F. containing several prominent nuclei. Musculature fessus. of both walls consists of longitudinal, tubular bun- Fessisentis females dles with contractile fibers at fessus are characterized periphery enclosing a central area of noncontractile cytoplasm. Elongate by subterminal genital pore. Although Van ganglion near posterior extremity of receptacle sac Cleave (1931) did not mention genital pore

Abbreviations: GL, genital ligament; IC, noncontractile cytoplasm of inner wall of contractile proboscis recepta- cle; IF, fibers of inner wall of receptacle; MS, muscularsheath of retinaculum;NF, nerve noncontractile fiber; OC, cytoplasm of outer wall of receptacle; OF, contractile fibers of outer wall of recep- tacle; RM, retractormuscle.

FIGURES 1-12. Camera lucida drawings of Fessisentis friedi nom. n., F. necturorum,Echinorhynchus salmonis, Acanthocephalusjacksoni, and F. fessus. (Projection between Figs. 1 and 12 applies equally to Figs. 1, 2, and 12. Projectionabove Fig. 4 applies equally to Figs. 3, 4, and 6. Projectionbetween Figs. 5 and 10 applies equally to Figs. 5 and 10.) 1. Proboscis of F. friedi. 2. Proboscis of F. necturorum. 3. x.s. through proboscis receptacle of E. salmonis. 4. x.s. through proboscis receptacle of A. jacksoni. FIGURES 5-12. F. fessus. 5. x.s. through trunk at level immediately posteriad to free end of proboscis receptacle. 6. x.s. through proboscis receptacle. 7-9. Variations in female genital pore position. 10. Terminal portion of proboscis receptacle with associated structures, dissected from trunk. 11. Egg re- moved from body cavity of fixed female. 12. Proboscis. 286 THE JOURNAL OF PARASITOLOGY,VOL. 58, NO. 2, APRIL1972 position in the descriptionand figured a female not resemble that in species of Fessisentis specimen with a terminalpore, the only female (Figs. 3, 4, 6). paratype examined possesses a distinctly sub- terminal genital pore. Female specimens col- Fessisentis vancleavi (Hughes and Moore, 1943), comb. n. lected from siren showed variation in genital pore position (Figs. 7-9), but 80 of 88 pos- Syn. Acanthocephalus vancleavi and Moore, 1943 sessed subterminal genital pores. The usual Hughes genital pore position is illustratedin Figure 7. Hughes and Moore (1943) described Acan- F. fessus is the only species of the genus char- thocephalusvancleavei from Euryceatynerensis acterized by females with subterminalgenital collected in Oklahoma. Their descriptionof an pores. extremely elongated "testicular field" with Althoughmonorchid specimens of Fessisentis boundariesbetween testes not clearly observed, fessus occur, it is the only species of the genus together with their illustrations of receptacle characterizedby two testes. sacs (Hughes and Moore, 1943, figs. 1, 5, 15), Van Cleave (1931) described Fessisentis is strongly suggestive of the genus Fessisentis. Materials fessus as possessing one retinaculum. This be- Examinationof a type specimen (see the came a unique characteristicof the Fessisen- section) confirmsthat the posteriorend of tidae. Subsequentstudy has demonstratedthat proboscis receptacle's outer wall is thickened F. fessus along with F. necturorumand F. van- into a pouchlike area containing several promi- with filiform cleavei possesses two retinacula (Figs. 5, 10). nent nuclei. Together the single Proboscisinvertor muscles penetrate the dorsal testis, this distinctive structure of the recep- wall of the receptacle sac and continue as a tacle strongly indicates that this species should to Fessisentis. Since it is now rec- pair of thin, closely associated retractor mus- be assigned cles. Careful study, including examination of ognized that Fessisentis possesses two retinac- transversesections, is often necessary to ascer- ula, A. vancleavei is substantiallyin agreement tain the double nature of these retractors(Figs. with the diagnosis of Fessisentis. and 5, 10). Recognition of nerve fibers in the reti- Hughes and Moore (1943) described in nacula permits distinction from retractormus- figured seven cement glands Acanthoceph- cles. alus vancleavei. Fessisentis is characterizedby of four cement It should be Species of Fessisentis differ from other acan- possession glands. usual number of cement thocephalansin muscularstructure of the pro- mentioned that the is also boscis receptacle sac. Descriptions by Kilian glands in species of Acanthocephalus other than seven. semi- (1932), Van Cleave and Bullock (1950), and Prominentlypouched Nickol and Holloway (1968) have resulted in nal vesicles of Fessisentis species frequently make determinationof cement number an understandingof the acanthocephalanpro- gland without of transversesections. boscis receptacle as a single- or double-walled impossible study Since anomalies and of cement structure with each wall consisting of either duplication are known to occur in the radial or circularcontractile fibers with a non- glands Acanthoceph- ala (Van Cleave, 1949; Bullock, 1962), it is contractile cytoplasmic portion evident as an felt that possession of other than four cement inner Musculatureof the receptacle sac lining. glands by one specimen of A. vancleavei should walls described here for F. is fessus (Fig. 6) not be emphasized to the point of obscuring invertormuscles and like that of proboscis rep- unique features shared with species of Fessi- resents a departurefrom usual acanthocephalan sentis. anatomy. All other species of Fessisentis ex- Fessisentis vancleavei is smaller than all amined in cross section (F. necturorumand F. other species of the genus in nearly every re- vancleavei) possess receptacle sac musculature spect except proboscishook length. The largest identical to that of F. fessus. Of the North hooks of F. vancleavei reach a length of 105 American fauna, Acanthocephalus and Echi- and the smallest45 (Hughes and Moore, 1943). norhynchus most closely resemble Fessisentis. These lengths far exceed those of comparable Proboscis receptacle musculature has been hooks in all other known species of Fessisentis. studied in A. jacksoniand E. salmonisand does Lemnisci of F. vancleavei are generally NICKOL-THE GENUS FESSISENTISIN NORTH AMERICANPOIKILOTHERMS 287 branched and These conditions are 6-7 7 7-6 a 6-9 9 90 10 10-11 11 subequal. * 0 known in other of Fessisentis, but are 13 species 1 * 0 not usual. 14 15 The known geographical distribution of F. - A A NW AAAAAA 00 0 vancleavei is restrictedto the vicinity of Tahle- 16 gE A.*&AA &A IA 0 0 quah, Oklahoma. Thus, it is the only species 17 0 of the genus known to occur west of the Missis- 18 n6A6 ono sippi River. 19 AA ? 2a A 0 Fessisentis friedi, nom. n. 21 (Fig. 1) Syn. Fessisentis vancleavei FIGURE13. Proboscisarmature of threespecies Haley and Bullock, 1953 of Fessisentisshowing number of longitudinalrows Transfer of vancleavei of hooks (verticalcolumns) and numberof hooks Acanthocephalus per row (horizontalrows). Data pertainingto Hughes and Moore, 1943, to Fessisentis neces- F. friedinom. n. are fromFried and Koplin(1967). sitates renaming F. vancleavei Haley and Bul- Each symbolrepresents a single specimen. Open lock, 1953. It is proposed that this species be symbolsrepresent females; solid symbolsrepresent males. F. renamed F. friedi in honor of Dr. Bernard Symbols: circles, friedi; squares, F. fessus; F. necturorum. Fried. Since Fried has contributed to our triangles, knowledge of this species, continuity in the literature is retained. Fessisentis necturorumNickol, 1967 Species of Fessisentis are highly variableand (Fig. 2) few, if any, single diagnostic characters are Although the original description of Fessi- recognized. Recognition depends upon com- sentis necturorumreported lemnisci from one parisonof many characters,the ranges of which to two times as long as the proboscisreceptacle frequently overlap at the extremes. Lemniscal (Nickol, 1967), their actual length was not length seems a relatively consistent difference given. Lemnisci of F. necturorumare 420 to among species. F. friedi possesses lemnisci 670 long in males and 770 to 880 long in fe- much shorter than those of F. fessus, shorter males. Lemnisci of F. necturorumare usually than those of F. vancleavei, and generally shorter than those of any other species of the longer than those of F. necturorum. Fried and genus. In regard to proboscis armature, F. Koplin (1967) reportedthat no branched lem- necturorum most closely resembles F. fessus nisci were observed among their specimens of (Fig. 13), but is distinguishedfrom it by pos- F. is the friedi. This, then, only species of session of a terminal genital pore in females, Fessisentis in which branched lemnisci have much shorter lemnisci, and smaller eggs. Pro- not been observed. Although proboscis shape boscis hooks of F. necturorum gradually de- is variable, F. friedi differs from other species crease in length proximallyand are not present of the genus by possession, in general, of a as two distinct size groups. F. necturorumre- long, cylindrical proboscis (Fig. 1) aimed, sembles F. friedi in many characters. Although especially in females, with more hooks per features of armature at the longitudinalrow (Fig. 13). proboscis overlap series of Fessisentisfriedi is recordedonly from south- extremes, specimens may be distin- eastern New Hampshire, southeastern Massa- guished by these characters (Fig. 13). In gen- chusetts (Haley and Bullock, 1953; Bullock, eral, F. necturorumalso differs from F. friedi pers. comm.), and from NorthamptonCounty, in proboscis shape and size (Figs. 1, 2, 12), Pennsylvania (Fried, Kitchen, and Koplin, receptacle sac length, lemniscus length, and 1964), suggesting that its distributionmay be testis width. limited to the northeasternedge of the Appa- Knowledge of host and geographical distri- lachian Mountains and the bordering coastal bution of Fessisentisnecturorum was increased plain. None of several fish and amphibian when Richard Heard discovered that it para- surveys from the Atlantic's southern coastal sitized Ambystoma opacum larvae in the vi- plain has reported presence of this species. cinity of Athens, Georgia. Previously F. nec- 288 THEJOURNAL OF PARASITOLOGY,VOL. 58, NO. 2, APRIL1972 turorum had been reported only from Necturus Koplin (1967) as F. vancleavei (= F. friedi). beyeri from southern Louisiana. They found F. friedi in Catostomus commer- Van Cleave's (1931) description of Fessi- soni collected in Northampton County, Penn- sentis has been emended by Haley and Bullock sylvania, present in fall and absent in spring (1953) and Fried and Koplin (1967). Addi- (May). Differences in seasonal distribution tional information from this study makes emen- may be local and may also vary with Fessisentis dation again necessary. Since specimens of all and host species. Collection data accompany- known species of the genus, including types of ing specimens provided by Bullock (see Mate- all except F. friedi, have been assembled for rials section) indicate that F. friedi parasitizes comparative study, the following redescription Lepomis gibbosus and Fundulus heterclitus at seems warranted. Newington, New Hampshire, during May. F. fessus was taken from Siren intermedia during Fessisentis Van Cleave, 1931 April and F. necturorum parasitizes Necturus Diagnosis beyeri in southern Louisiana from February November. were not ex- Fessisentidae parasitic as adults in gilled sala- through Waterdogs manders and freshwater fishes. Trunk elongate amined during December and January. and devoid of spines. Proboscis of varying length, A series of 16 siren collected in Union with clavate to cylindrical, and armed longitudinal County, Illinois, does not represent an extensive rows of rather weak hooks. Proboscis receptacle but it that intensity of infec- sac double-walled with posterior thickening con- sample, suggests increase with host size taining several prominent nuclei. Each muscular tion and worm size wall composed of tubular bundles with contractile (age). Two siren from this collection with fibers confined to periphery. Brain in posterior snout-vent lengths exceeding 200 mm harbored third of sac. Two retinacula receptacle penetrate 47 and 49 specimens of Fessisentis fessus. extremity of receptacle and insert on posterior Gravid females from these hosts were 31 to 51 lateral body walls. A pair of thin retractormuscles leaves posterior tip of receptacle and inserts poste- mm long. Ten infected siren with snout-vent Thick riorly on dorsal wall of trunk. ligament lengths less than 100 mm harbored a maximum strand inserts at of posterior extremity receptacle of seven Gravid and does not always persist in males; always rup- (median, two) specimens. tures in females. Male reproductive system occu- females from this host group were 23 to 39 pies 60 to 80% of body cavity length and includes mm long. Mean lengths of these two groups 1 or 2 filiform testes and 4 cement Uterine glands. are significantly different with the chance of bell with large pockets. Female pore terminal to subterminal. Eggs elongate; fertilizationmembrane alpha error less than 5%. Little information is elongated at poles, but lacking polar knobs. available concerning longevity of palaeacan- F. fessus Van Cleave, 1931, by Type species: thocephalans. In known instances (Van Cleave, original designation. 1916; Crompton and Whitfield, 1968) species DISCUSSION of survive less than 1 year Fried, Kitchen, and Koplin (1964) reported in the definitive host. It seems likely, therefore, fluctuation in seasonal distribution of a Fessi- that differences in specimen size and infection sentis species later identified by Fried and intensity of F. fessus in siren are related to

TABLE I. Comparisonof morphologicalfeatures of mature Fessisentis fessus collected from heavy and light infections. Numerals in parentheses indicate size of sample upon which mean measurements or counts are based.

Infections < 10 worms Infections > 45 worms Male (16) Female (18) Male (24) Female (31)

Trunk length (mm) 17 28 20 41 Proboscis length 268 323 268 325 No. long. rows Prob. hooks 17 19 17 19 No. hooks/row 7 7 7 7 Length largest hooks 40 48 40 50 Lemniscus length (mm) 2.8 3.6 2.9 3.9 Egg length (through body) -92 -94 NICKOL-THEGENUS FESSISENTIS IN NORTHAMERICAN POIKILOTHERMS 289

available space and increased food (interme- observations on variability. J. Parasit. 48: diate host) intake respectively in larger siren. 442-451. D. W. AND P. WHITFIELD. The that older siren CROMPTON, T., J. 1968. possibility exists, however, The course of infection and egg production of accumulate acanthocephalans during successive Polymorphus minutus () in years of life. Dr. John D. Lynch, University of domestic ducks. Parasitology 58: 231-246. Nebraska, placed the age of those specimens FRIED, B., J. G. KITCHEN, AND R. S. KOPLIN. 1964. An intestinal helminth of Catostomus under 100 mm in length at approximately 1 study commersoni from the Bushkill Creek, North- and that of the two over 200 mm at 3 year or ampton County, Pennsylvania, with observa- more years. In spite of larger female worms in tions on seasonal distribution of Triganodisto- older hosts with heavy infections, Table I gives mum sp. (Trematoda) and Fessisentis sp. evidence that infection and host (Acanthocephala). Proc. Pa. Acad. Sci. 38: intensity age 95-98. do not relate to of other variability morpho- ,AND R. S. KOPLIN. 1967. Morphological logical features. variation of Fessisentis vancleavei Haley and Knowledge acquired subsequent to Van Bullock, 1953 (Acanthocephala) from the Cleave's description of Fessisentis has gradually white sucker, Catostomus commersoni (La- eroded the distinctive characters of the c6pede). Proc. Pa. Acad. Sci. 40: 53-58. genus GOLVAN,Y. J. 1969. Systematique des Acantho- until its place as the only genus of Fessisen- c6phales (Acanthocephala Rudolphi, 1801), tidae has been questioned. In deference to l'ordre des PalaeacanthocephalaMeyer, 1931, possession of four cement glands, Golvan (1969) la super-famille des Echinorhynchoidea (Cob- bold, Golvan et 1963. Mem. transferred eight genera of Echinorhynchoidea 1876) Houin, Mus. National Hist. Nat. Nouvelle serie A, to Fessisentidae. Van Cleave (1931) discussed Zool. 42: 1-373. the unusual number of cement glands in Fessi- HALEY,A. J., AND W. L. BULLOCK. 1953. A new sentis, but felt that it merely supported family species of Acanthocephala from the sunfish, level distinctness of other characters. In view Lepomis gibbosus (Linnaeus), with a rede- of the Fessisentidae Van of the fact that the nuclear at the scription family pouch pos- Cleave, 1931. Am. Midi. Nat. 50: 202-205. terior extremity of the outer wall of the probos- HUGHES, R. C., AND G. A. MOORE. 1943. Acan- cis receptacle, muscular construction of the thocephalus van-cleavei, a new echinorhynchid from receptacle walls, and form of testes are, as worm, a salamander. Am. Midi. Nat. 29: 724-729. far as known, unique, family level recognition KILIAN, R. 1932. Zur Morphologie und Syste- would seem merited. Until other genera with matik der Gigantorhynchidae(Acanthoceph.). these characters are known, the family Fessi- Ztschr. Wiss. Zool. 141: 246-345. sentidae is characterized by Fessisentis, the MALEWITZ, T. D. 1956. Intestinal parasitism of included some mid-western salamanders. Am. Midi. only genus. Nat. 55: 434-436. NICKOL, B. B. 1967. Fessisentis necturorum sp. ACKNOWLEDGMENT n. (Acanthocephala: Fessisentidae), a para- In addition to those persons acknowledged site of the , Necturus in the Materials section for beyeri. J. Parasit. 53: 1292-1294. providing speci- , AND H. L. 1968. Mor- mens of the author is indebted to HOLLOWAY,JR. Fessisentis, phology of the presoma of Corynosoma ham- Drs. John D. Lynch and Michael J. Smith, anni (Acanthocephala: Polymorphidae). J. University of Nebraska, who provided consid- Morph. 124: 217-226. erable assistance in collection of Siren inter- VAN CLEAVE, H. J. 1916. Seasonal distribution of some media. Dr. Ronald A. Southern Illi- Acanthocephala from fresh-water Brandon, hosts. J. Parasit. 2: 106-110. nois was in University, especially cooperative 1931. New Acanthocephala from fishes arranging laboratory facilities and overnight of Mississippi and a taxonomic reconsideration accommodations near LaRue Swamp. of forms with unusual numbers of cement glands. Tr. Am. Micr. Soc. 50: 348-363. LITERATURECITED 1949. An instance of duplication of the cement glands in an acanthocephalan. Proc. ALTIG, R. 1967. Food of Siren intermedia net- Helm. Soc. Wash. 16: 35-36. in a in southern tingi spring-fed swamp Illinois. ANDW. L. BULLOCK. 1950. Morphology Am. Midi. Nat. 77: 239-241. of Neoechinorhynchusemydis, a typical repre- BULLOCK,W. L. 1962. A new species of Acan- sentative of the Eoacanthocephala. I. The thocephalus from New England fishes, with praesoma. Tr. Am. Micr. Soc. 89: 288-308.