Acanthobothrium cairae
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Ordo: Tetraphyllidea
Familia: Onchobothriidae
Genus: Acanthobothrium
Name
Acanthobothrium cairae Mitchill – Wikispecies link – Pensoft Profile
- Acanthobothrium cairae Vardo-Zalik, Anne M., 2011, Zootaxa 2838: 43-47.
Materials Examined
Type locality: Narragansett Bay off Sakonnet Point, Rhode Island, coll. R. A. Campbell. Site of Infection: spiral intestine. Prevalence:3 of 10 individuals examined.
Etymology
Etymology: The species is named after Dr. Janine Caira, University of Connecticut, for her contributions to the study of cestode systematics and taxonomy.
Description
Description: Based upon measurements of 8 whole mounted specimens, SEM of 2 specimens and serial sections of 8 specimens. Large worms 45–154mm (104, n= 8) long, maximum width at gravid segments, 960–1060, composed of 268–491 (401, n= 8) segments. Strobila muscular; mature segments acraspedote, apolytic. Scolex proper 1100–1440 long by 1200–1460 wide. Scolex, composed of 4 triloculate bothridia, loculi separated by two thick muscular septa, bothridia free at posterior ends with velum between adjacent bothridia. Bothridia 975–1225 (1063, n= 15) long by 550–725 (630, n= 10) wide rounded posteriorly, covered with spinitriches over proximal surfaces; apical sucker and pad present, armed with one pair of bifid hooks. Anterior loculus 500–700 (558, n= 12) long, middle loculus 175–275 (214, n= 12) long, posterior loculus 100–150 (116, n= 12) long; ratio of locular lengths (A: M: P) 1: 0.38: 0.21; mean (BL: BW) 1.7: 1. Apical pad rounded 225–400 (347, n= 12) long by 450–650 (498, n= 12) wide; accessory sucker 125–250 (180, n= 10) wide. Hooks symmetrical, stout, prongs markedly unequal, handles about equal in length. Cephalic peduncle 2740–4600 (3179, n= 7) long by 520–800 (618, n= 7) wide, covered with spinitriches; internal muscle bundles clearly visible, junction of neck most discernible when contracted; (BL: CPL) 1: 1.16 when contracted; (BL: CPL) 1: 1.9 to 2.9 when relaxed. Neck 1600 to 3800 long, transcending into first narrow segments of strobila. Hook dimensions: Lateral hook (n= 5): A= 60 (n= 4); B= 125–238 (195) with large pore; C= 113–163 (133) very curved; D= 275–350 (330); E= 250–313 (290); W= 100–125 (113). Medial hook (n= 5): A’= 60 (n= 4); B’= 188–225 (208) with large pore; C’= 125–138 (128) very curved; D’= 300–375 (338); E’= 250–300 (275); W’= 100–125 (108). (THL: BL) 1: 3.1 to 1: 3.2. Strobila: Strobila robust with 4 pairs of large longitudinal muscle bundles extending throughout (Figs. 6–8). Immature segments wider than long 259–476 (384, n= 8) per worm, gradually elongating with appearance of genital anlagen. Mature segments, number 9–39 (17, n= 8) per worm, 1.1 to 1.4 times longer than wide, 700–1725 (949, n= 22) long by 550–1200 (756, n= 22) wide. Gravid segments trapezoidal, 920–1260 long by 960–1060 wide; length to width ratio 1.11–1.32: 1 (1.21, n= 10). Genital pores 36–66 % (54 %, n= 20) of total length from posterior end of segment, irregularly alternating; genital atrium shallow. Cirrus sac near equatorial in immature segments; postequatorial in mature segments, 150–350 (210, n= 21) long by 60–225 (105, n= 21) wide; pyriform in gravid segments, slightly larger c. 375 by 250. Cirrus armed. Testes 82–166 (118, n= 16) in number, slightly subspherical, 50– 100 (63, n= 26) long by 60–100 (67, n= 26) wide, arranged 2–3 deep in intervascular fields anterior to ovarian isthmus, rarely posterior to isthmus (Figs. 3, 7, 8); testes atrophied in oldest segments. Testis distribution: 26–65 (41, n= 20) preporal, 42–85 (65, n= 20) aporal, 12–23 (16, n= 20) postporal. Vas deferens extensive forming 10 or more transverse loops filling most of preovarian intervascular region (Fig. 5). Ovary U-shaped, bilobed in cross section, at posterior end of segment, 300–520 (445, n= 16) wide in mature segments, poral lobe 200–540 (285, n= 19) long, reaching level of cirrus sac and slightly beyond (Figs. 3, 5); aporal lobe 250–620 (363, n= 19) long reaching midlevel to near anterior border of cirrus sac; ovary up to 875 wide with lobes up to 450 long in gravid segments. Mehlis’ gland conspicuous, rosette-like mass surrounding ootype, diameter 40–50, at center of ovarian isthmus. Vagina thick-walled, extending in midline from ootype to level of cirrus sac, then continues laterally along anterior margin of cirrus sac as enlarged thick-walled duct to genital atrium; seminal receptacle present; vaginal sphincter absent. Vitellarium follicular in 2 lateral columns c. 200 wide, extending most of segment length; each column 5–6 follicles deep in cross section; follicles ellipsoidal, 32–64 long by 16–24 wide. Vitelline follicles not reaching limits of testicular field anteriorly or full extent of ovary posteriorly; interrupted by cirrus sac and vagina on poral side. Uterus median, broad, columnar, covered with dark staining glandular cells, extends anteriorly from shell gland, ends near anterior extremity, expanded in gravid segments. Uterine pore and eggs not observed. Dorsal and ventral osmoregulatory canals variable in diameter, dorsal canal 20–33 in diameter, ventral canals 20–64 in diameter.
Discussion
Remarks:Acanthobothrium cairae is the third species of Acanthobothrium reported from the roughtail ray, Dasyatis centroura being preceded by A. paulum and A. woodsholei. Acanthobothrium cairae is very large and muscular with stout hooks and qualifies as a category 3 species (LMMA) according to the system of Ghoshroy& Caira (2001). Both A. paulum and A. woodsholei are smaller category 1 (SFFS) and 2 (7) (S(L)FFA) respectively with delicate hooks and strobila unlike A. cairae. Species of Acanthobothrium comparable to A. cairae in the western Atlantic Ocean and waters of the Gulf of Mexico and Carribean Sea are: A. americanum from Dasyatis americana Hildebrand & Schroeder from Chesapeake Bay, Virginia; A. coronatum from species of skates (Rajidae) by Linton (1901, 1924) at Woods Hole, Massachusetts and by Meyers (1959) in the Gulf of St. Lawrence, Canada; and A. tortum from Aetobatus narinari (Euphrasen) in the Gulf of Mexico. Acanthobothrium cairae differs from A. americanum, a category 6 species, in possessing more testes per segment (82–166 vs. 59–78), larger hooks (275–375 vs. max. 180), and asymmetrical hook prongs (188–225 vs. 125–138). Acanthobothrium cairae has longer bothridia (975–1225 vs. 500–660), larger anterior loculi (500–700 vs. 200–350), and fewer postporal testes (12–23 vs. 26–44) than A. tortum. Linton’s (1901, 1924) reports of A. coronatum, a species common to the eastern North Atlantic and Mediterranean Sea (Williams 1969), were considered in error and corrected by Baer (1948) and Baer & Euzet (1962) with the descriptions of A. woodsholei and Acanthobothrium septentrionale Baer & Euzet, 1962. Acanthobothrium woodsholei is smaller than A. cairae (12 –15 mm vs. 45–154 mm) with fewer testes (50–55 vs. 82–166). Specimens of A. coronatum reported by Meyers (1959) from the skates Dipturus laevis (Mitchill), Leucoraja ocellata (Mitchill), and Amblyraja radiata (Donovan) were undescribed and unavailable for comparison; therefore the trans-Atlantic distribution of A. coronatum could not be confirmed. Two species in the south Atlantic, Acanthobothrium ramiroi Ivanov, 2005 from Argentina and Acanthobothrium terezae Rego & Dias, 1976 from Brasil, in freshwater stingrays (Rajiformes, Potamotrygonidae) are similar in size to A. cairae. Both species parasitize Potamotrygon motoro (Müller & Henle) and are distinguished from A. cairae in having dissimilar hooks (hooks similar in A. cairae), and symmetrical vs. asymmetrical ovarian lobes. In the North Atlantic, Acanthobothrium icelandicum Manger, 1972 from Raja batis (Linnaeus) is a category 3 species having hooks with prongs of unequal length. Important characters differentiating A. cairae from A. icelandicum are greater size (to 154 mm vs. 67.4 mm), absence of a vaginal sphincter, U-shaped vs. H-shaped ovary, and internal musculature of 8 large muscle bundles (4 dorsal, 4 ventral) in cross-sections of A. cairae vs. 6–10 dorsal and 7–14 ventral in A. icelandicum. In hosts from European waters and the Mediterranean, Acanthobothrium cairae is similar to A. crassicolle, A. intermedium, A. coronatum, Acanthobothrium rajaebatis (Rudolphi, 1809), A. septentrionale and Acanthobothrium zschokkei Baer, 1948. Williams (1969) considered all of these species to be in need of further study but recognizable by their hosts (none from stingrays) and hook formula. Acanthobothrium septentrionale from Raja sp. in the North Atlantic is a category 3 species that differs from A. cairae in smaller total hook length (123–129 vs. 275– 375) and fewer testes (60–90 vs. 82–166). Goldstein (1967) and Manger (1972) both indicate that there are 3 accessory suckers per bothridium in A. septentrionale though neither Baer & Euzet (1962) nor Williams (1969) make mention of it.
Taxon Treatment
- Vardo-Zalik, Anne M.; Campbell, Ronald A.; 2011: Five new species of Acanthobothrium van Beneden, 1849 (Cestoda: Tetraphyllidea) in elasmobranchs from the northwest Atlantic and Gulf of Mexico with first records from smooth-hound sharks and guitarfish, Zootaxa 2838: 43-47. doi
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