Qatar Univ. Sci. J. (1992), 12: 115- 123 REVIEW OF THE GENUS POLYMORPHUS LUHE, 1911 (ACANTHOCEPHALA:POLYMORPHIDAE), WITH THE SYNONYMIZATION OF HEXAGLANDULA PETROCHENKO, 1950, AND SUBCORYNOSOMA HOKLOVA, 1967, AND A KEY TO THE SPECIES OMAR M. AMIN Department of Biological Sciences, University of Wisconsin-Parkside, Kenosha, Wisconsin 53141, USA '~" ~,_,J '-""LSJ~--":1 ~ ii • ? 'r '1~~~~ ~~ FJJ ( ':?~J~~ : U"'i}l u~~ ) tl_,;a}U CUioJ ~o~I,:WS \ ~ i V LS,_,Js~ lA~~,;JS.:al....uJ \ ~ o • ~~ ~J ~~u, '"'n >-'t... ~~JJ-!= ) ..,..u,;~J:I ~ ..::.'-'fi...J ~~J ~J ,•.:.:•; ~~ ll.A <.) ~ ..w _;~I~ ~I 1-4] ~-'-7- ~J r=..~.i:> ~ d.l.:6:. 4:]..1:' ( ''\IV Li~-'""' ~~t....., ''\ o • ~~ ~~1}-:1, ''\~A . ~..l1 ~>" ,_) ~..ll_;;... ''\IV l.i~_,...,. L:._,.......~~L....J ''\ o • ~~ ~Y.~~~ ~I _;~IJ , ..,..J.i,;~J:I ~ J! ( ~.J-:1 ..,..~,;~,;1 ) ~.J-:1 ..,..u,;~J:' .>..l~LJ ~ ..::.1~ u.- ~..li t... ~ U.OJ t_,.JI ~J .J ~~J , L:t~ ..,..u.;~J:' t_,.;.ll ~J ~t:;J • ~..)1;;.. ..,..b~ ..,..u.;~J:'J vu:at.:-to ..,..u,;~J:' n ~J '"''' (S"_,l ..,..u,;~J:I L:...A.bli ~ ~ .....ilji£.~1 ~ ..liJ. u~_,...,. ...:i..4..li W> '"' ~ o ~ .:,l.i ..,..ts~ ..,..u,;~J:' - . tly~l ol.A ~ .....i_;.a:;.J.J c~ l":'.u:; ~ W>' ti,Y1 '. ~J '"'n >-'L:. ~~JJ-!J' tc._,. Key Words: Acanthocephala, Polymorphus, Review, Profilicollis, FaJsifiJicoJJis, Parafilicollis, Subfilicollis, Subcorynosoma, Hexaglandula, Key to species. ABSTRACT The position, concept and composition of the genus Polymorphus (=Profilicollis Meyer, 1931; Fa/sifilicollis Webster, 1948; Parafilicollis Petrochenko, 1950; Subfilicollis Hoklova, 1967) are critically evaluated and a new diagnosis of the genus is proposed based on the designation of Hexaglandula Petrochenko, 1950 and Subcorynosoma Hoklova, 1967 as junior synonyms. Other taxonomic changes proposed include the reassignment of Polymorph us brevis ( = Arhythmorhynchus brevis) back to Polymorph us, the synonymization of Polymorphus magnus with Polymorphus minutus, the recognition of Polymorphus pupa and of the questionable status of· Polymorphus trochus Van Cleave, 1945 sensu Hoklova, 1966. Hoklova's subgenera are reviewed and rejected. Only two subgenera are recognized, Polymorphus Luhe, 1911 with 36 species and ProfiJicoJJis Meyer, 1931 with 10 species. A key to species of the genus is provided. INTRODUCTION and was not consistent with other decidedly Polymorph us species which also have 6 cement glands, e.g., Polymorphus cetaceum (Johnston and Best, 1942) Schmidt and Dailey, 1971, and The discovery of Polymorphus spindlatus by Amin and Polymorphus arctocephali Smales, 1986. The relationship be­ Heckmann (1991) brought into focus the present confused tween Polymorphus and related genera, particularly Arhyth­ taxonomic state of the genus Polymorphus Luhe, 1911. The morhynchus, need clearer definition. The relationship between concept of the genus changed considerably since Luhe first Polymorphus and Profilicollis also needs to be more clearly erected it for Polymorphus minutus (Goeze, 1782) Luhe, 1911. elucidated since certain species of Polymorph us have the type of Some diagnoses are barely recognizable as of Polymorphus. A egg characteristic of Profilicollis. The different subgeneric number of species of Polymorph us were assigned to Profilicollis assignments to Polymorphus, see for example Amin (1985) and Meyer, 1931; Falsifilicollis Webster, 1948; Parafilicollis Pet­ Hoklova (1986), are assessed and certain synonymies and new rochenko, 1956; Subfilicollis Hoklova, 1967; Arhythmorhynchus assignments are made. Luhe 1911; Filicollis Luhe, 1911 and Plagiorhynchus Luhe, 1911 ( = Prosthorhynchus Kostylev, 1915) that were placed in various It is hoped that this study will provide the necessary definition families and subfamilies. One or more of these genera/subgenera to clarify the taxonomic status of this complex genus. The work were later either synonymized with, or reduced to, subgenera of is presented in a historic context in order to relate the evaluation Polymorphus. The erection of Hexaglandula by Petrochenko of the concept of Polymorphus to its present status and (1950) for forms with 6 cement glands caused more confusion composition as conceived by various authors. 115 Review of the genus polymorphus lube THE POSITION, CONCEPT, AND COMPOSITION OF Webster, 1948. POLYMORPHUS Petrochenko (1956) erected Filicollidae for Filicollis Liihe, 1911 including only F. anatis (Schrank, 1788) Liihe, 1911, and The characteristic generic of features of Polymorphus, erected Parafilicollis Petrochenko 1956 including P. major, P. altmani, for only one species, P. minutus (Goeze, 1782), by Luhe (1911) P. kenti and P. sphaerocephalus. His three major diagnostic included small body size, body wall nuclei, grid-like lacunar features of Parafilicolliswere the long neck, spheroidal proboscis system, trunk spines anterior to constriction, radially symmetric­ and eggs without polar prolongation of middle membrane. al proboscis hooks which decreases in size anteriorly and Additional features included unpronounced sexual dimorphism, posteriorly, double-walled proboscis receptacle with brain near anterior trunk spines not well defined in young females, and 4-6 its posterior end, long neck, moderately long lemnisci, testes tubular cement glands. Petrochenko (1956) placed Parafilicollis behind one another, tubular cement glands, genital opening in Gigantorhynchidae Southwell and MacFie, 1925 based pri­ terminal without spines, and eggs with polar prolongation of marily on the egg shape. Schmidt and Kuntz (1967) declared middle membrane. Except for features like the long neck or the Parafilicollis as without status because Meyer (1931) erected position of the testes and possibly the distribution of the body Profilicollis for the same concept. The shape of eggs was clearly wall nuclei, the above diagnosis remains largely valid today. As shown to be of no diagnostic value at the generic level in the number of species included in the genus increased, the Polymorphida:e by Van Cleave (1939), Schmidt and Kuntz (1966, generic concept continued to expand to accommodate them. 1967) and Amin (this paper). Many of the diagnostic features added by various authors were too restrictive to be of generic value as the interspecific Golvan (1960-61) accepted Profilicollis ( = Falsifilicollis Webs­ variability within Polymorphus continued to increase with the ter, 1948) as a subgenus diagnosed with spheroidal proboscis and discovery of more species. These restrictive diagnostic features long slender neck, and included the same four species listed by are noted in the following few paragraphs. Webster (1948), but without indicating a subgenus for the other Southwell and MacFie (1925), who discussed only P. minutus, species of the genus. Yamaguti (1963) synonymized Profilicollis diagnosed the body as thickened anteriorly and the proboscis as with Polymorphus, and Parafilicollis with Webster's, 1948 subcylindrical. Travassos (1926) recognized Polymorph us under Falsifilicollis which he amended and elevated to the generic subfamily Centrorhynchinae (Van Cleave, 1916) of family status. Yamaguti's (1963) diagnosis of Falsifilicollis was essen­ Echinorhynchidae Cobbold, 1879 but Thapar (1927) included it tially the same as that of Petrochenko's (1956) of Parafilicollis in his new family Acanthogyridae and order Acanthogyridea. except for his reference to proboscis armature (16-30 longitudin­ The inconsistencies in Travassos's (1926) system, based on the al rows of 7-12 hooks each), 4-8 tubular cement glands, and use of insufficiently constant characters, were not satisfactorily tandem testes. Yamaguti (1963) included Falsifilicollis and eliminated in Thapar's (1927) scheme which recognized separate Filicollis in Filicollidae Petrochenko, 1956 which he correctly families as comp~sites. ~ · transferred to Echinorhynchidea Southwell and MacFie, 1925. Clearly Falsifilicollis and Parafilicollis occupy the same concept In Meyer's (1931) system, Polymorphus was correctly placed for which Meyer (1931) originally erected Profilicollis. These in his family Polymorphidae and order (Class) Palaeacan­ three taxa are also clearly synonymous with Polymorphus since thocephala, and included 14 species (Meyer, 1932) all of which the subgenus Profilicollis was erected by Golvan (1961) for are presently recognized members of the genus except P. magnus Webster's (1948) original subgenus Falsifilicollis. It is thus which is here synonymized with P. minutus (following section). logical to assign subgeneric status to PolymorphusWebster, 1948 In his brief diagnosis, Meyer (1932) restrictively referred to short and to Profilicollis (Meyer, 1931) Golvan, 1961 as Schmidt and compact bodies cylindrical or weakly ovoid proboscides, trunk Kuntz (1967) correctly proposed. spines anterior to mid constriction, tubular cement glands, string-like lemnisci, and numerous small nuclei in the body wall. While the above subgeneric controversies were going on, the Meyer (1931) also established a new genus, Profilicollis, for two diagnosis of the genus Polymorph us was undergoing changes of long-necked species Polymorphus boi:ulus and Polymorphus its own. Even though with the erection of Hexaglandula arcticus (=Filicollis botulus Van Cleave, 1916 and Filicollis Petrochenko, 1950, which is here synonymized with Polymor­ arcticus Van Cleave, 1920) with eggs with concentric mem­ phus (see status of Hexaglandula following), Petrochenko (1958) branes, but kept Filicollis Liihe, 1911 for Filicollis anatis removed part of the inconsistencies from his