New Annotated Records of Helminth Parasites with Light Microscopy II. Acanthocephala (Polymorphida)

Centrorhynchus spinosus (Kaiser, 1893) Van Cleave, 1924

Polymorphida (Centrorhynchidae) (Figures 1, 2) Van Cleave [2] (p. 513) corrected the record of C. spinosus in his following statement “Echinorhynchus spinosus was originally described by Kaiser from an unrecorded host from Florida.” The present writer (Van Cleave) [3], misinterpreting Kaiser’s description, described and renamed the same species Centrorhynchus spinosus (based on one female_). Several birds, all from Florida, have been listed as hosts for this species.” The acanthocephalan has been since found in Russia [4] and Van Cleave [2] also described females from the “Galapagos hawk”. We have 2 males and one fragmented gravid female collected from _Strix aluco Linn. by Dr. Ali Halajian in Iran representing new records. All internal structures of the female were obscured by eggs. This appears to be a host-specific parasite found in only very few hosts including the great grey owl Strix nebulosa Forster in Russia [4].

Available measurements of females especially those by Van Cleave [2, 5, 6] were confused giving trunk length of 20.00-60.00 mm, proboscis length of 0.65-1.00-1.30 mm, 30- 34 proboscis hook rows of 22-24 hooks each measuring 38- 48-60 long anteriorly and 50 posteriorly. Van Cleave [5] gave a count of 24 hooks per row but reported in 1924 9-12 rooted hooks anteriorly and 14-16 spine-like hooks posteriorly. He [6] (p. 296) emphasized “the great variability in the size of the proboscis hooks and thorns..…that were even continuous in the same females.” The determination of C. spinosus from India by Pujatti [7] was apparently in error as recognized by Golvan [8]. Similarly, Schmidt and Neiland [9] also recognized erroneous identifications of three Old World parasites of hawks that have the same number and arrangement of hooks as C. spinosus. Yamaguti (1963, p.126) referred to 30.00-45.00 mm long males and Nickol’s [10] description of C. spinosus summarized previous taxonomic treatments and is used here as a reference point for comparison. Richardson and Nickol [11] provided a useful key to species of Centrorhynchus in North America which identifies C. spinosus with 8-11anterior hooks in each longitudinal row and with trunk lacking anterior conspicuous inflation which agrees with our specimens. Similarly, Khokhlova [12] discussed the status of C. spinosus in the USSR and provided a key of the 15 known species of Centrorhynchus there.

First Description of Male Centrorhynchus spinosus from Strix aluco in Iran: Based on two mature adults; one is fragmented. Trunk long, cylindroid, slightly inflated anteriorly, 23.37 mm long by 0.92 wide anteriorly. Proboscis (Fig. 1) 0.95-1.09 long. Anterior proboscis 525-650 long by 333-354 wide with 9-14 rooted hooks per row measuring maximum of 52-75 anteriorly and becoming most robust at middle and transitional posteriorly. Posterior proboscis 315-425 long by 364-385 wide with 8-9 curved spiniform hooks per row measuring maximum of 45-48 anteriorly. Internal anatomy of proboscis shows receptacle process (Fig. 1). Proboscis receptacle double walled, 1.30-1.37 mm long by 0.27 mm wide with cephalic ganglion near middle. Lemnisci longer than receptacle, 2.17 mm long by 0.16 mm wide. Testes close but not contiguous, 0.62-1.07 mm long by 0.40-0.50 m wide, pre-equatorial, 4.50 mm from anterior trunk. Four tubular cement glands 11.25 mm long by 0.42 mm wide anteriorly. Saefftigen’s pouch 2.80 mm long. Eggs oblong with concentric shells and some polar prolongation of fertilization membrane (Fig. 2).

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Figures 1-6: Morphology of polymorphid acanthocephalans from wildlife. 1, 2. Proboscis and egg of an adult Centrorhynchus spinosus from Strix aluco in Iran. Note the receptacle process (Fig. 1) 3. Anterior portion of a cystacanth of Centrorhynchus spinosus from Osteopilus septentrionalis in Florida. 4, 5. Proboscis and eggs of Sphaerirostris lancea from Vanellus vanellus in Ukraine. 6. Proboscis of Sphaerirostris picae from Pica pica in Bulgaria.

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Figures 7-12: Morphology of polymorphid acanthocephalans from wildlife. 7. Eggs of Sphaerirostris picae. 8. Partially invaginated proboscis of Sphaerirostris picae. 9, 10. Proboscis of Plagiorhynchus (Prosthorhynchus) nicobarensis from Sturnus vulgaris in Iran. Note the basal hooks in perfect circle (Fig. 10). 11, 12. Anterior portion and proboscis of Andracantha gravida male from Gavia immer in Florida.

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Figures 13-18: Morphology of polymorphid acanthocephalans from wildlife. 13, 14. Middle and posterior hooks and anterior trunk spines of the male specimen. 15. Proboscis of Arhythmorhynchus brevis from Casmerodius albus in Florida. 16-18. Anterior parts of a male Southwellina hispida from Ardea cineria in Macedonia showing the comparable shape and size of the lemnisci and the receptacle as well as the anterior half of the proboscis. Note the small round testes (Fig. 17).

• Specimens: Deposited at the Harold W. Manter Laboratory (HWML) Parasitology Collection no. 217063, Lincoln, Nebraska.
• Remarks: Compared to specimens described by above quoted observers, our specimens were only very mildly inflated at anterior trunk and at middle of proboscis and had a fewer spiniform hooks per row (8-9) in posterior proboscis. The number of the anterior rooted hooks was considerably more stable than that of the more variable posterior spiniform hooks. However, 8-10 spiniform hooks per row were counted in Khokholova’s [12] (Fig. 83b) specimens from Russia, the Volga region, Western Siberia, Azerbaijan, Kazakhstan, and Turkmenistan, even though she reported 10-15 such hooks per row. In addition, the testis appeared more rounded and separated in the Russian specimens of Khokhlova [12]

(Fig. 82c, p. 168). The proboscis of specimens from Louisiana [10] was extremely wide at middle; unlike our specimens or the Russian material. The eggs in our gravid female specimen were fusiform, 52-58 long by 20-25 in diameter, with blunt tips, concentric rings and minor polar prolongation (Fig. 2). Except for minor differences in measurements and the distant rounded testes, our specimens from Iran were morphologically most similar to those reported by Khokhlova [12] from Russia to Turkmenistan. Lisitsyna [13] reported Ukrainian specimens with a total of 23 hooks including transitional ones, and 8-10 spiniform hooks (Fig. 39a), testes very close to each other as in our specimens, but the lemnisci were very thick finger-like. In our specimens, the anatomy of the proboscis (Fig. 1) shows the receptacle process previously demonstrated in Sphaerirostris picae (Rudolphi, 1819) Golvan, 1956 by Amin, et al. [14].

Centrorhynchus spinosus (Kaiser, 1893) Van Cleave, 1924 cystacanths

Polymorphida (Centrorhynchidae) (Figure 3) We obtained 2 cystacanths of C. spinosus collected from a Cuban tree frog Osteopilus septentrionalis (Duméril & Bibron) in Tampa, Florida where the species was originally described. Nicole found the worms in the “small intestine area” of the body cavity in July, 2008, making the tree frog a paratenic host; a new record. Other species of frogs have been listed as paratenic hosts of various species of Centrorhynchus [15]. The proboscis armature of the two specimens fit that of the description of adults given above and keyed out to C. spinosus using the key of Richardson and Nickol [11] allowing for variations due to the different developmental stage.

The cystacanths (Fig. 3) had a bluntly pointed encased ovoid-shaped trunk, 1.42-1.47 mm long by 0.57-0.62 mm wide. Proboscis 1.06 mm long with 25-26 rows of 26 hooks each, divided by a mild constriction into 2 parts. Anterior proboscis 603-624 long by 218-260 wide, slightly inflated with 13 rooted hooks per row measuring 45-50 subapically; most robust hook just posterior to inflation. Posterior proboscis gradually widening basally, with 12-13 curved spiniform hooks per row measuring 35-37 posteriorly. Receptacle twisted and primordia of lemnisci visible. • Specimens: Deposited at the Harold W. Manter Laboratory (HWML) Parasitology Collection no. 217064, Lincoln, Nebraska.

Sphaerirostris lancea (Westrumb, 1821) Golvan, 1956

Polymorphida (Centrorhynchidae) (Figures 4, 5) Golvan [8] created Sphaerirostris as a subgenus of Centrorhynchus Lühe, 1911 with 21 species and several synonymies later increased to 26 species [16]. Twenty valid species are currently recognized [14]. Proboscis armature was a primary criterion distinguishing species apart. Sphaerirostris lancea is known from birds in the families Scolopacidae, Turdidae, Charadridae, Burhinidae, Recurvirostridae, Cuculidae in the Palearctic as well as in China, Taiwan, Egypt, and the USA [13, 17]. Lisitsyna provided us with 6 specimens (2 large females and 4 smaller males) from the lapwing Vanellus vanellus (Linn.) collected in Ukraine in 1988 [12]. Lisitsyna [13] provided detailed descriptions of S. lancea from Ukraine and Petrochenko [17] described it under Centrorhynchus from Russian Turkestan after Skryabin [18]. The brief description by Khokhlova [12] and her figure no. 86 are directly based on those provided by Petrochenko [17].

• General description: Trunk ovoid anteriorly and cylindrical posteriorly. The length proportion of the anterior ovoid to the posterior cylindrical trunk was 1:1.3-1.5 in our largest gravid females. This proportion was 2.3:1 in the specimens from Ukraine (Lisitsyna, [13]) (Fig. 1a) and the specimens from Russia (Petrochenko [17], Fig. 108). In our younger male specimens, the proportion was closer to 1:1. Cylindrical posterior trunk appearing to grow at a faster rate than the anterior trunk in maturing females. Proboscis in two parts; spheroid anteriorly and cylindrical posteriorly (Fig. 4). Anterior 7-8 hooks on anterior proboscis largest with prominent roots directed posteriorly followed by a transitional hook. Last 3 hooks smaller, slenderer with miniature anteriorly directed roots. Proboscis receptacle double- walled with spherical cephalic ganglion slightly posterior to its middle. Two slender, finger-like equal lemnisci not reaching anterior testis, attached posteriorly with filaments to body wall.

• Males: Based on 4 mature specimens with sperm. Trunk 5.87-11.00 mm long with anterior ovoid trunk 3.75- 6.75 (5.40) mm long by 1.12-1.87 (1.56) mm wide and posterior cylindrical trunk 2.12-4.37 (3.49) mm long by 0.42-0.82 (0.64) mm wide. Total proboscis 600-700 (640) long by 300-350 (330) wide anteriorly, with 11- 13 hooks per row. Proboscis receptacle 0.82-0.92 (0.88) long by 0.25-0.27 (0.26) wide. Lemnisci 1.50-1.57 mm long by 0.13 mm thick in one 11.00 mm long male. Testes in anterior trunk, ovoid, nearly contiguous. Anterior testis 0.82-1.05 (0.94) mm long by 0.42-0.50 (0.47) mm wide. Posterior testis 0.67-1.25 (1.00) mm long by 0.45- 0.50 (0.46) mm wide. Cement glands unequal, beginning at level of posterior testis, 2.10-4.25 (3.42) mm long by 0.12-0.17 (0.14) mm wide. Saefftigen’s pouch 0.75-1.30 (1.07) mm long by 0.25-0.50 (0.37) mm wide anteriorly.

• Females: Based on 2 large gravid specimens. Trunk 16.12-17.5 mm long with anterior ovoid trunk being 7.12-7.50 mm long by 2.35-2.40 mm wide and posterior cylindrical trunk being 9.00-10.00 mm long by 1.15- 1.37 mm wide. Total proboscis 603-832 long by 416 wide anteriorly, with 11-12 hooks per row. Proboscis receptacle 0.86-1.04 mm long by 0.28 wide. Genital pore subterminal and eggs ellipsoidal with concentric membranes (Fig. 5), 42-48 long by 17-22 wide.

• Specimens: Deposited at the Harold W. Manter Laboratory (HWML) Parasitology Collection no. 217065.

• Remarks: All measurements fell within the range recorded by Petrochenko [17] and Lisitsyna [13] except that the eggs were somewhat immature and smaller. In the specimens from Ukraine, the eggs appeared oblong with rounded ends (Lisitsyna [13], Fig. 4), the lemnisci were thick, the testes were round and distant, and the cement glands began at the level of anterior testis (Lisitsyna [13], Fig. 41a). In the specimens from Russia, the testes were ovoid and contiguous [17, 18], like ours.

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Figures 19, 20: Morphology of polymorphid acanthocephalans from wildlife. Two eggs of Southwelliona hispida from Nycticorax violaceus in Florida showing the rounded polar prolongation of the fertilization membrane characteristic of this species.

Sphaerirostris picae (Rudolphi, 1819) Golvan, 1956

Polymorphida (Centrorhynchidae) (Figures 6, 7) Petrochenko [17] did not recognize Golvan’s [8] Sphaerirostris and did not include S. picae among his keyed out 51 species of Centrorhynchus. Khokhlova [12] did not include S. picae among her keyed out 11 species of Sphaerirostris and Yamaguti [4] recognized S. picae under Centrorhynchus and Lisitsyna [13] provided a detailed description of S. picae among 5 species of Sphaerirostris from Ukraine that she keyed out. Amin, et al. [14] recognized 20 valid species of Sphaerirostris, redescribed S. picae from Pica pica (Linn.) in Iran, discussed its seasonal distribution, and compared its intraspecific variability in populations from Iran, Bulgaria, Hungary, Ukraine, Armenia, France, and Russia. Amin, et al. [14] also described a special receptacle process at the anterior end of the proboscis receptacle extending into the proboscis. A similar structure was previously described in Corynosoma hamanni (Linstow, 1892) by [19, 20]. Radwan, et al. [21] studied the epidemiology of S. picae in Egypt.

In the present study, we evaluate the intraspecific variability in 4 additional populations of S. picae from Ukraine (provided by Olga Lisitsyna), Bulgaria (by Zlatka Dimitrova), Iran (by Ali Halajian), and Egypt (by Nahla Radwan) (Table 2) to compare with that in eight other populations reported earlier in Amin et al. [14].

*All measurements are in micrometers except where otherwise noted. Extreme measurements are bolded. Table 2:** Intraspecific variability among populations of Sphaerirostris picae from various hosts in Ukraine, Iran, Bulgaria and Egypt.

• General Description: Based on specimens from all new 4 populations. Trunk fusiform, spheroid. Anterior proboscis with flat apical end and cylindrical-conical posterior proboscis with more widely spaced spiniform hooks and fewer hook rows (Fig. 6). No significant sexual differentiation in proboscis armature. Anterior hooks strong, 5th hook usually largest, with prominent roots followed posteriorly with transitional then smaller posterior hooks with anteriorly directed roots. Receptacle double-walled with oval cephalic ganglion near its center, lemnisci longer than receptacle and not reaching anterior testis.
• Males: Testes pre-equatorial, occasionally overlap. Four cement glands staggering anteriorly at level of posterior testis and joining posteriorly in 2 cement reservoirs. Subterminal gonopore.
• Females: Vagina with 2 sphincters, genital opening terminal in juveniles but subterminal in mature adults, and eggs oval with external sculpturing and concentric shells (Fig. 7).
• Specimens: Deposited at the Lincoln, Nebraska Harold W. Manter Laboratory (HWML) Parasitology Collections nos. 217066, 217067, 217068, 217069 from Ukraine, Bulgaria, Iran, & Egypt, respectively.
• Remarks: Table 2 provides a taxonomic comparison among the 4 populations of S. picae studied here. Specimens of the four populations appear similar with measurements falling within the same range of intraspecific variations, with minor exceptions marked by bolded font. Amin, et al. [14] noted that “confusion in the taxonomy of S. picae …. can be traced to intraspecific variability among various geographical populations and the choice of variable taxonomic criteria to distinguish between them.” A similar study was performed in 8 populations of another species of Acanthocephala, Mediorhynchus papillosus Van Cleave, 1916 from 11 host species in Europe, Taiwan, and the USA by Amin and Dailey [22] who noted that “Distinctiveness of geographical populations appears to be related to geographical restrictions, intermediate and definitive host specificity and distribution, and host feeding behavior.”

Plagiorhynchus (Prosthorhynchus) cylindraceus (Goeze, 1782) Schmidt & Kuntz, 1966

Polymorphida (Plagiorhynchidae) (Figure 8) Schmidt and Kuntz [23] synonymized Prosthorhynchus Kostylew, 1915 with Plagiorhynchus Lühe, 1911 and reduced the two genera to subgenera of the genus Plagiorhynchus s. lat. We have 3 semi-contracted adult females of (P.) (P.) cylindraceus that we have not previously reported. Two specimens collected from a common blackbird Turdus merula Linn. in Iran by Dr. Ali Halajian in 2011, and one specimen from a starling Sturnus vulgaris Rafinesque in Kenosha, Wisconsin by Bob Sewell in autumn, 1974. Available measurements include only proboscis size 1.07-1.14 mm long by 0.27 mm wide, largest proboscis hooks 83-94 long, number of hooks per row 13-14, and receptacle size 1.99-2.00 mm long by 0.32-0.36 mm wide.

• Remarks: The shape of the cylindrical proboscis and hooks (Fig. 8), and the above measurements are compatible with those described for P. (P.) cylindraceus from South Africa [24] or its synonyms Plagiorhynchus formosus (Van Cleave, 1918) Travassos, 1926 from North America and Plagiorhynchus taiwanensis Schmidt and Kuntz, 1966 from Taiwan or from Ukraine) [13], and Russia [12]. The contorted shape and limited measurements available in our 3 specimens from Iran and Wisconsin do not avail further detailed morphometric comparisons with specimens from other populations. Only Amin, et al. [24] provided detailed comparisons between P. (P.) cylindraceus and its synonyms P. (P.) formosus, and P. (P.) taiwanensis.
• Specimens: Deposited at the Lincoln, Nebraska Harold W. Manter Laboratory (HWML) Parasitology Collections nos. 217070, 217071 from Iran and Wisconsin, respectively.

Plagiorhynchus (Prosthorhynchus) nicobarensis (Soota & Kansal, 1970) Zafar & Farooqui, 1981

Polymorphida (Plagiorhynchidae) (Figures 9, 10) This acanthocephalan was originally described from 3 females collected from the ground thrush Zoothera citrina (Latham) at the Car Nicobar, India by Soota and Kansal [25] (Table 3). Ten years later, Zafar and Farooqui [26] redescribed it from an unknown number of males collected from warblers on mainland India. We are describing P. (P.) nicobarensis for the first time from the common starling in Iran; new host and locality records, and comparing its morphometrics with those in the original descriptions (Table 3).

• Description of our Iranian Specimens: Trunk elongated-fusiform. Proboscis cylindrical with hooks in parallel longitudinal rows with strong posteriorly directed roots except basal rootless spiniform hooks (Figs. 9, 10). Anterior hooks except apical largest. Basal hooks in perfect ring. Receptacle double-walled with cephalic ganglion near middle, lemnisci long, subequal, reaching posterior testis. Testes oval, contiguous, pre-equatorial, anterior testis occasionally totally overlapping proboscis receptacle. Cement glands 4, tubular, in 2 pairs. Saefftigen’s pouch prominent, pyriform, thick walled, overlapping posterior end of cement glands. Female reproductive system long, with subterminal gonopore, one sphincter and long straight uterine bell. Eggs elliptical with concentric shells.
• Specimens: Deposited at the Harold W. Manter Laboratory (HWML) Parasitology Collection no. 217072, Lincoln, Nebraska.

*All measurements in micrometers unless otherwise noted. Extreme measurements are bolded. Table 3:** Comparative morphometries between specimens in the original description of Plagiorhynchus (Prosthorhynchus) nicobarensis from India and our specimens from Iran.

The morphology and organization of the Iranian specimens was similar to that of specimens in the original descriptions but showed variations. The measurements of all structures were comparable (Table 3). However, males from Iran had relatively smaller trunk and reproductive structures and females had slightly smaller eggs. Males from Aligarh had smaller basal hooks and females from Nicobar were reported with fewer proboscis hook rows. In general, Indian specimens had somewhat smaller receptacle. The above variations are considered to be of intraspecific nature in the various geographical populations. Updates to the key to species of Plagiorhynchus (Prosthorhynchus) in Amin, et al. [24] will need to take the above variations into account. The 3 definitive hosts (Table 3) are omnivorous and insectivorous [27, 28] and their invertebrate diet must include intermediate hosts commonly infected with larval acanthocephalans in India and Iran. For instance, invertebrates like the isopod Aramadillidium vulgare Latreille are naturally infected with plagiorhynchid acanthocephalans like P. cylindraceus that commonly infect starlings [29, 30].

Andracantha gravida (Algret, 1941) Schmidt, 1975

Polymorphida (Polymorphidae) (Figures 11-14) Schmidt [31] erected the genus Andracantha for 3 species of Corynosoma Lühe 1904 with two fields of trunk spines and genital spines that he redescribed. Andracantha gravida was originally described as Corynosoma gravida by Alegret [32] from the double crested cormorant Phalacrocorax auratus floridanus (Audubon) in Cuba. The description and measurements of the Cuban material fell within the range of those described by Schmidt [31] (with proboscis length correction) also from the brown pelican Pelecanus occidentalis carolinensis Gmelin from Florida and Louisiana.

We currently possess one adult male specimen (Fig. 11) collected by DJF from a common loon Gavia immer (Brunnich) in Franklin County, Florida on 28 June, 1983. This is a new host record for A. gravida. Our male specimen is similar to those described by Schmidt [31] but with some distinct variations. Our specimen was smaller, 2.62 mm long by 1.05 wide but with similar measurements of proboscis (675 by 250) (Fig. 12), receptacle (1.02 mm by 0.27 mm wide), cement glands (280 by 146), largest dorsal hook (73 by 31 wide at base), largest ventral hook (83 by 31 wide at base) (Fig. 13). Posterior hooks smallest compared to largest anterior trunk spines (Fig. 14). Equal length of anterior, trunk and genital spines (30-33) but somewhat smaller testes (400 by 275) (Fig. 11). The distribution of anterior and trunk spines was similar to Schmidt’s [31] specimens but our male specimen had only 1 genital spine as opposed to 18 marked in Schmidt’s [31] (Fig. 2).

• Specimens: Deposited at the Harold W. Manter Laboratory (HWML) Parasitology Collection no. 217073, Lincoln, Nebraska.

Arhythmorhynchus brevis Van Cleave, 1916

Polymorphida (Polymorphidae) (Figure 7) Schmidt [33] recognized two types of acanthocephalans in the former assemblage of Arhythmorhyynchus Lühe, 1911. “In one, the posterior trunk is very long and slender and the anterior trunk has one field of spines …(with) two or four cement glands. These are Arhythmorhynchus. In the second form, the anterior trunk has two fields of trunk spines in at least one sex, the posterior trunk is much shorter, and there are four cement glands. This group…. represents Southwellina” (Schmidt [33], p. 300). This species was originally described as A. brevis based on already prepared museum specimens by Van Cleave [5]. Travassos [34] assigned the species to genus Polymorphus and Meyer [35] accepted this generic assignment. Van Cleave [36] re-examined the status of the species from additional collections and re-assigned it back to Arhythmorhynchus based on his “belief that … the species is in agreement with the accepted concepts of the genus Arhythmorhynchus” and that Meyer’s [35] relegation “apparently” based on his interpretation of the proboscis as “either weakly ovoidal or possibly approaching cylindrical form” was in error (Fig. 15). He did not refer to the reason for the re-assignment by Travassos [34]. For more on the turbulent nomenclature history of A. brevis, see Amin [37].

MGS gave us two whole-mounted darkly stained specimens, a male and a female that were collected from a great egret Casmerodius albus (Linn.) in Florida. Exact date and locality were not noted but other collections from the same source were from Franklin County in June, 1983. Measurements of our specimens are in Table 4 compared to those from the descriptions of Van Cleave [5, 36].

• Specimens: Deposited at the Harold W. Manter Laboratory (HWML) Parasitology Collection no. 217074, Lincoln, Nebraska.

• Remarks: Van Cleave’s [5, 36] accounts were incomplete, not including measurements of lemnisci, receptacle, testes, cement glands, or cement gland ducts. Van Cleave did not count the number of cement glands but he (Van Cleave [36], Fig. 1) showed what appears to be 2 glands which is in agreement with Schmidt [33] of 2 or four glands in Arhythmorhynchus. However, our specimen appears to have more than 2 glands. Van Cleave’s [36] (Fig. 1) also appears to show a lemniscus reaching to anterior end of posterior testis as it does in our male specimen. We could not delineate the whole female reproductive system (nor did Van Cleave) but the gonopore was between subterminal to near terminal with a simple vagina adjoining an unremarkable sphincter. Van Cleave (2016) described eggs with rounded swellings at the polar ends of “middle” membrane. Our female specimen had only large elongate ovarian balls.

*All measurements in micrometers unless otherwise noted. Extreme measurements are bolded. Table 4:** Comparative morphometrics between specimens in the original description of Arhythmorhynchus brevis from Japan and our specimens from Florida.

Southwellina hispida (Van Cleave, 1925) Witenberg, 1932

Polymorphida (Polymorphidae) (Figures 16-20) Schmidt [33] resurrected the genus Southwellina Witenberg, 1932 and redefined it. Van Cleave [38] described S. hispida as Arhythmorhynchus hispidus from 4-5 mm long immatures in Illinois, USA and Fukui [39] redescribed it under the same name from 6 males and 13 females that infected Nycticorax n. nycticorax Linn. in Japan.

One of the synonyms of S. hispida is Polymorphus ardeae Belopolskaia [40] seven specimens of which were sent to us in February, 2008 for evaluation. Konstantinos Oyreilidis and Basil Ragias from Kavala, Greece sent 6 whole mounted males and 1 female collected from Ardea cinerea Linn. collected at the lagoons Vassova and Eratino of the River Nestos Delta in East Macedonia, Greece. They, among others [41] posted a report on these specimens as P. ardeae, the name under which their specimens were sent to us in 2008. Despite this universally accepted synonymy, it should be noted that, irrespective of measurements, these two synonyms differ markedly in proboscis shape (ovoid in P. ardeae but expanded medially in S. hispida) as well as the morphology of hook roots especially the posterior hooks having long anterior manubria in S. hispida (Amin, et al. [42], Fig. 2) and being without roots posteriorly and anteriorly in P. ardeae (see Belopolskaia [40], Fig. 1).

Only 2 male specimens from Macedonia, Greece were informative, one partially. The other specimens were totally corrupted with processing plaques. The anteriorly swollen trunk of our male specimens measured 3.37-8.75 mm long by 1.25-2.25 mm wide. Anterior trunk spines 22 long. Spindle-shaped proboscis 775-875 long by 325-350 wide at middle swelling (Figs. 16,18) with 24 rows of 14- 16 hooks each. Largest hook 50-57 long by 17-20 wide at base. Posterior hooks with prominent and straight anterior manubria. Receptacle 1.50-1.52 mm long by 0.42-0.45 mm wide. Lemnisci inflated, superficially similar to receptacle in shape (Figs. 16,17) and about as long, 1.50 long by 0.28-0.32 wide. Testes round, almost equal, post-equatorial, oblique to nearly side by side (Fig. 17), anterior testis 235 by 235, posterior testis 225 by 225. Bursa round, 550-650 long by 550-675 in diameter.

Comparatively, our specimens from Macedonia were somewhat smaller than those described by Fukui [39] from Japan in size of trunk and testes. Fukui [39], however, described the testes in his specimens as tandem or very slightly oblique (his Fig. 34) and the lemnisci were club- shaped and very long, about 2-3 times as large as the receptacle (his Fig. 27b). The receptacle and lemnisci in our specimens were about equally long (Fig. 17). The proboscis and receptacle were larger in our specimens and the armature was comparable. Van Cleave [38] described the species from 5 juveniles in Japan that are best described in detail by Amin, et al. [42] who described juveniles from California.

Our single gravid female specimen from Florida provided by DJF from the yellow-crowned night heron Nycticorax violaceus (Linn.) was larger in all common measurements (10.25 mm long by 3.25 wide) than the male specimens with anterior trunk spines 30 long, proboscis 936 long by 350 at middle swelling with 16 hooks per row, largest hook 63 long by 27 wide at base. The gravid female specimen from Florida was slightly smaller than the female from Macedonia but provided measurements of eggs of 80-95 by 22-28 that had the rounded polar prolongation of the fertilization membrane characteristic of this species (Figs. 19, 20). Other measurements and counts were comparable to those in Van Cleave [38] and Fukui [39]. • Specimens: Deposited at the Lincoln, Nebraska Harold W. Manter Laboratory (HWML) Parasitology Collections nos. 217075 and 217076 from Macedonia and Florida, respectively.