Parorchis catoptrophori, Dronen & Blend, 2008

Dronen, Norman O. & Blend, Charles K., 2008, Observations on the Parorchis acanthus complex (Philophthalmidae: Parorchiinae) with the description of three new species of Parorchis Nicoll, 1907 and the replacement of the preoccupied junior homonym Paratrema Dronen & Badley, 1979 with Stenomesotrema nomen novum, Zootaxa 1843 (1), pp. 1-23 : 7-10

Parorchis catoptrophori n. sp.

( Figs. 6–9)

Type host: Willet, Catoptrophorus semipalmatus (Gmelin) , Charadriiformes , Scolopacidae .

Type locality: Vicinity of Galveston , Galveston County, Texas, U.S.A. (29 º 18' N latitude, 94 º 48' W longitude) .

Site of infection: lower intestine.

Deposited specimen s: USNPC holotype 100616, USNPC voucher (1) 100617 .

Prevalence: 4 of 8 willets, 50%.

Intensity: 1–3 per infected bird.

Etymology: The species is named for the genus of the host bird, Catoptrophorus Bonaparte.

Description: Based on 6 adult specimens. Body distinctly pyriform, heavily spinose along periphery and on ventral surface of anterior 60-65% of body, moderately large, 4,963 (4,225 –5,700) long by 2,135 (1,325 – 2,575) wide; body spines, bullet-shaped, moderately pointed, generally scale-like, 18 (15–22) long by 12 (10– 15) wide; forebody 1,650 (1,475 –1,825, approximately 33% of body length) long by 1,075 (975–1,175) wide, anterior end surrounded by well-developed, shoulder-like head collar 860 (760–970) wide, bearing a single row of 82 (80–85) spines; dorsal collar spines, blunt, nearly oval, 22 (21–24) long by 16 (13–18) wide; ventral corner spines similar in shape to body spines, 24 (21–26) long by 13 (11–15) wide, typically 14–15 per side. Mouth subterminal; oral sucker wider than long, 380 (335–425) long by 400 (350–435) wide; prepharynx short, 35 (20–50) long; pharynx bipartite, composed of larger, anterior, muscular primary pharynx, 195 (170– 230) long by 130 (110–150) wide, followed by smaller posterior nonmuscular part composed of 2 smaller posterior extensions, 74 (55–90) long by 60 (45–70); ratio of width of pharynx to width of oral sucker 1:3.1 (1:2.9–3.3); esophagus long with 9-12 shallow, notch-like diverticuli, 795 (755–835) long; ceca long, simple, terminating near posterior extremity. Acetabulum large, 900 (820–975) long by 915 (820–1,005) wide, sucker ratio 1:2.3 (1:2.2–1:2.3). Testes side by side, deeply lobed, near posterior extremity; left testis 235 (170–310) long by 280 (210–345) wide; right testis 295 (210–385) long by 260 (175–350) wide; intertesticular space 130 (90–175); posttesticular space 560 (545–580) long. Genital pore immediately anterior to acetabulum near midline of body; cirrus sac lateral width 165 (105–225), enclosing cirrus and prostate gland cells, lacking an internal seminal vesicle; external seminal vesicle enclosed in sac-like membrane, extending short distance posterior to posterior margin of acetabulum, 1,210 (1,020 –1,395) long by 140 (110–165) wide, anterior 75% narrow (approximately 40–50 wide) expanding into distinctive posterior, seminal chamber (approximately 310 [225–385] long by 145 [120–165] wide). Ovary oval to round, situated immediately anterior to intertesticular space, about 130 (100–160) anterior to level of testes, near midline of body, 195 (175–215) long by 235 (210–245) wide; ratio of width of ovary to average width of testes 1:1.1 (1:0.9–1:1.4). Ootype immediately postovarian, on midline of body. Morphologically distinct seminal receptacle absent. Laurer’s canal not observed. Vitelline follicles distributed in lateral fields from level of posterior margin of acetabulum posteriorly to level of posterior margin of ovary. Uterus filling hindbody from midlevel of testes to level of acetabulum, extracecal uterine loops present, proximal end unmodified, filled with spermatozoa; metraterm well developed 155 (130–180) long by 40 (35–55) wide. Eggs variable in size, eggs prior to miracidial eyespot development 61 (57–65) long by 38 (33–43); eggs with fully developed miracidia 87 (83–91) by 47 (44–53); no miracidia free in uterus. Excretory vesicle slender, Y-shaped, branching at level of mid-posttesticular space; excretory arms with moderate branching, anterior extent of arms not observed. Excretory pore slightly subterminal on dorsal surface.

Remarks: Parorchis catoptrophori n. sp. is unlike P. acanthus , as originally described by Nicoll (1906) (subtype 1 of the Parorchis body type described above), by having a larger body size (4,963 long compared to 3,910); a definite prepharynx (35 long compared to absent); and a longer esophagus with prominent diverticuli (795 compared to short to “absent” [“the intestine almost immediately divides into two wide branches” after the pharynx] with 9–12 diverticuli compared to lacking diverticuli). The new species also has a bipartite pharynx composed of a large, muscular, anterior part and a smaller posterior extension; more collar spines (82 [80–85] compared to “about 60” [actual count = 54]); a smaller oral sucker (400 wide compared to 500); a larger ratio of the width of the pharynx to the width of the oral sucker (1:3.1 compared to approximately 1:2.6, as calculated from Figure 4 of Nicoll [1906]); a smaller acetabulum (915 wide compared to 1,080); smaller testes (average width of testes 270 compared to 550), the testes are irregular and deeply lobed compared to being “circular” and smooth to slightly irregular (not deeply lobed); and the testes of P. catoptrophori n. sp. are not contiguous (intertesticular space 130 compared to 0).

The new species is similar to the specimens used in the redescription of P. acanthus by Nicoll (1907b) (subtype 2 of the Parorchis body type described above) by having a definite prepharynx, a long esophagus that has diverticuli, testes that are deeply lobed, and both species are about the same size (4,225 –5,700 compared to 3,000 –5,000). It differs from these specimens of P. acanthus by having more collar spines (82 compared to about 60); a smaller oral sucker (400 wide compared to 500; although Nicoll [1907b] reported the width of the oral sucker to be 500, it appears to be only about 370 wide, as calculated from Figure 1 of Nicoll [1907b], in which case, the oral sucker would be larger in the new species); a shorter prepharynx (35 long compared to 110); and a bipartite pharynx. It further differs from the specimens used in the redescription of P. acanthus by Nicoll (1907b) by having a slightly larger ratio of the width of the pharynx to that of the oral sucker (1:3.1 compared to approximately 1:2.9 using 170 for the width of the pharynx and 500 as the width of the oral sucker as reported by Nicoll [1907b]; or 1:1.3 using approximately 280 wide and 370 wide, respectively, as calculated from Figure 1 of Nicoll [1907b]); a smaller acetabulum (915 wide compared to 1,080; although Nicoll [1907b] reported the width of the acetabulum to be 1,080, it appears to be about 840, as calculated from Figure 1 of Nicoll, [1907b], in which case, the acetabulum would be larger in the new species); and smaller testes (average width of testes 175–350 compared to 550–600).

The new species can be distinguished from all species of Parorchis , including P. longivesiculus n. sp. and Parorchis ralli n. sp. described herein, except P. chauhani by having the pharynx composed of 2 parts, a larger anterior primary pharynx and a smaller posterior pharyngeal extension; and from all species where the collar spine counts have been reported by having more collar spines (80–85). It also can be distinguished from all species assigned above to subtype 2 of the Parorchis body type by having a larger ratio of the width of the pharynx to the width of the oral sucker (1:3.1 compared to 1:2.0). Parorchis chauhani is a distinctive species in that it also appears to have a bipartite pharynx, the anterior, primary pharynx of which is wider than it is long (110 long by 118 wide). Fischthal & Kuntz (1975) considered the posterior part of the bipartite pharynx as the upper part of the esophagus, but in their illustration, it appears to be a posterior extension of the pharynx, as is seen in P. catoptrophori n. sp. The nature of this feature could not be verified in the holotype of P. chauhani [USNPC 72891]). Parorchis chauhani also has an ovary (240 wide) that is larger than the testes (159 average width). The new species differs from P. chauhani by having a larger body size (4,963 long by 2,135 wide compared to 2,795 by 1,298), larger suckers (oral sucker 400 wide compared to 240; acetabulum 915 wide compared to 580), a larger primary pharynx (130 wide; ratio of the width of the pharynx to the width of the oral sucker 1:3.1 compared to 118; 1:2.0 that is longer than wide), larger testes (average testes width 270 compared to 159, where the testes are larger than the ovary), slightly larger eggs (83–91 long by 44–53 wide compared to 61–72 by 26–32); and the new species has more collar spines (82 compared to 61). Although they have been reported from different regions of the world ( Russia and Brazil, respectively), P. parvicollis and P. snipis are very similar to each other; primarily differing in the size of their gonads (ovary approximately 340 compared to 140; average testes width 633 compared to 225). Parorchis catoptrophori n. sp. can be further distinguished from these 2 species by having a larger body size (4,963 long compared to 2,530 and 2,580) and larger suckers (oral sucker 400 wide compared to 286 and 270; acetabulum 915 wide compared to 584 and 550). The new species is similar in overall size to P. schachtachtinskoi (4,963 long by 2,135 wide compared to 4,448 by 1,408); however, it differs from this species by having a smaller pharynx (anterior part 195 long by 130 wide compared to approximately 240 by 210), a smaller acetabulum (915 wide, sucker ratio 1:2.3 wide compared to about 1,080, 1:2.9, as calculated from Figure 1 of Dadasheva & Filimonova [1978]), and by having a longer external seminal vesicle (1,210 long compared to about 950, as calculated from Figure 1 of Dadasheva & Filimonova [1978]). The new species has a somewhat smaller body size than P. proctobium (4,225 –5,700 long by 1,325 –2,375 wide compared to 5,000 –7,000 by 3,000 –4,000 [measurements from Shtrom 1927]), smaller suckers (oral sucker 400 wide compared to 530, acetabulum 820–1,005 wide compared to 1,000 –1,159 [measurements from Shtrom 1927]), a smaller primary pharynx (130 wide compared to 190), smaller gonads (ovary 235 wide compared to 400; average width of testes 270 compared to 870), and by having smaller eggs (57–91 long compared to 134–142). Parorchis catoptrophori n. sp. is most like P. avitus , but in addition to the differences given above, the new species has a distinct prepharynx, a smaller pharynx (130 wide compared to 188), smaller gonads (ovary 235 wide compared to 245; average width of testes 270 wide compared to 585, as calculated from Figure 3 of Linton [1914]), and the anterior 75% of the external seminal vesicle of P. catoptrophori n. sp. is a narrow canal that expands into a distinctive posterior seminal chamber rather than being elongated and club-shaped. Parorchis magnus n. comb. is somewhat similar to the new species, but is much larger (7,500 –7,800, compared to 4,963 [4,225 –5,700]), it has a larger pharynx (260–274 compared to 110–150) and P. magnus n. comb. has smaller testes (average testes width 178 compared to 270).

It is interesting to note that a second species of Parorchis was found in C. semipalmatus that was collected in an inland area of west Texas (HWML 38223; USNPC 84757). This second species could not be identified because of the marginal quality of the specimens, but it does not have the distinctive bipartite pharynx present in P. catoptrohori n. sp. described above.