Cardicola covacinae, Nolan & Cribb, 2006

Nolan, Matthew J. & Cribb, Thomas H., 2006, Cardicola Short, 1953 and Braya n. gen. Digenea: Sanguinicolidae) from five families of tropical Indo-Pacific fishes (, Zootaxa 1265 (1), pp. 1-80 : 23-26

Cardicola covacinae n. sp.

( Figs 19–22 )

Type host: Siganus punctatus (Schneider) , Goldspotted Rabbitfish ( Perciformes : Siganidae ).

Site in host: Bulbus arteriosus (heart).

Type locality: Heron Island, southern Great Barrier Reef (23º26’S 151º54’E), Queensland .

Material examined: ex S. punctatus, Heron Island ( QLD), Feb. 2002, Feb. 2005, two specimens (no QM G 225224 ) (one specimen sequenced for ITS2) .

Prevalence of infection: Two of sixteen S. punctatus from Heron Island infected with two specimens .

Collector: M.J. Nolan.

Etymology

Specific name for our good friend Ms Cath Covacin of the School of Molecular and Microbial Sciences (UQ).

Description

Based on one whole mount. With features of genus. Body elliptical, 658 x 116, 5.7 times longer than wide ( Figure 19 ). Tegumental spine rows 5–8 (6) wide, width consistent along margin, 5–8 spines per row with 5 in most. Nerve chords conspicuous; nerve commissure 90 or 14% of body length from anterior end. Oral sucker vestigial, transversely rhomboidal, 18 x 28, delimited posteriorly by fine membrane, bearing unknown number of concentric rows of fine spines ( Figure 20 ). Mouth 5 from anterior end. Oesophagus sinuous, narrow anteriorly, width consistent from posterior margin of nerve commissure, ventral to intestinal bifurcation, surrounded by gland cells from posterior margin of nerve commissure, 390 or 59% of body length. Intestine X­shaped; anterior caeca unequal, right anterior caecum 80 long, left anterior caecum 77 long, length 12% of body length, wider than posterior pair; posterior caeca unequal, thin, convoluted, right posterior caecum 330 long, left posterior caecum 304 long, length 46% of body length, 3.9 times longer than anterior pair, terminal extremities expanded. Testis elliptical, margins irregular, almost entirely intercaecal, extending laterally to field medially, terminating before posterior margins of posterior caeca, 154 or 23% of body length x 64 or 55% of body width, 2.4 times longer than wide. Vas deferens originating anterior to posterior margin of testis, passing posteriorly medially, sinuous, expanding distally to form seminal vesicle. Seminal vesicle elliptical, 83 or 13% of body length from posterior end, 57 x 20, 2.9 times longer than wide ( Figure 21 ). Ejaculatory duct straight, directed postero­dorsally; prostatic cells not seen. Male genital pore sub­marginal. Ovary bilobed, posterior to and abutting posterior margin of testis, intercaecal anteriorly, posteriorly extending past intercaecal field, does not pass laterally to field, dorsal to vas deferens, 33 or 5% of body length x 49 or 42% of body width, 156 or 24% of body length from posterior end. Oviduct originating anterior to centre of posterior margin of ovary, passing postero­dextrally, expanding to form small oviducal seminal receptacle, narrowing laterally to anterior margin of seminal vesicle, continuing posteriorly as narrow tube, joining with vitelline duct lateral to seminal vesicle. Oviducal seminal receptacle rhomboidal, posterior to posterior margin of ovary, 28 x 10, 2.8 times longer than wide. Vitelline duct seen anterior to posterior margin of ovary, passing posteriorly ventral to ovary, oviducal seminal receptacle, oviduct and vas deferens, expanding to form vitelline reservoir lateral to posterior margin of ovary, narrowing again anterior to posterior margin of oviducal seminal receptacle. Oötype ovoid, postero­sinistrally directed, posterior to male genital pore, 28 x 10. Mehlis’ gland not seen in single specimen examined here. Uterus passing latero­sinistrally from oötype, convoluted, at medial body line looping antero­dorsally, dextrally, passing anteriorly to anterior margin of oviducal seminal receptacle as non­convoluted tube, dorsal to vitelline duct, oviduct, oviducal seminal receptacle, vas deferens and seminal vesicle, here loops antero­ventrally, dextrally across midline dorsal to ovary and vas deferens, level with termination of left posterior caecum loops postero­dextrally to metraterm ( Figure 22 ). Metraterm convoluted, passing dorsoanteriorly, then posteriorly to genital pore, 41 x 18. Female genital pore opening dorsomedially, lateral to posterior margin of oviducal seminal receptacle, anterior to seminal vesicle, antero­dextral to male genital pore. Eggs ovoid, elongate, 20–33 (26) x 13–15 (14) wide (n=3). Vitellarium follicular, anteriorly extending past nerve commissure to near posterior margin of vestigial oral sucker, posteriorly extending to joining of vitelline duct and oviducts duct dextrally, and male genital pore sinistrally, anteriorly dorsal to lateral m; 21, 22, 100 m. nerve chords, both dorsal and ventral to oesophagus, intestine and testis, posteriorly ventral to ovary and uterus, both dorsal and ventral to oesophagus, oesophageal gland tissue, intestine, testis, ovary and uterus. Excretory vesicle oblanceolate; collecting ducts seen extending anteriorly. Excretory pore terminal.

Remarks

The new species agrees well with the characters of Cardicola and is immediately distinguished from Cardicola coeptus n. sp. (the second species from S. punctatus off Heron Island) in having the combination of a body 5.7 times longer than wide, oesophageal glands that extend posteriorly to the intestinal bifurcation, posterior caeca that are convoluted and that extend 46% of the body length and a testis that is almost entirely intercaecal, lanceolate and 2.4 times longer than wide. This species differs further in having an ovary that extends posteriorly to the intercaecal field, is bilobed and has a width 42% of the body width, a uterus that is entirely posterior to the posterior caeca and vitelline follicles that extend anteriorly past the nerve commissure and posteriorly to the level of the male genital pore. In contrast, C. coeptus n. sp. possesses a body 3.2–4.1 times longer than wide, oesophageal glands that extend posteriorly to the anterior margins of the anterior caeca, posterior caeca that are straight but irregular and that extend 28–38% of the body length and a testis that extends laterally to the intercaecal field, is square and 0.9–1.1 times longer than wide. Cardicola coeptus n. sp. also has an ovary that does not extend posteriorly to the intercaecal field, is transversely oblanceolate and has a width 62–69% of the body width, a uterus that extends anteriorly into the intercaecal field and vitelline follicles that extend anteriorly to the posterior margin of the nerve commissure and posteriorly to the posterior margin of the oviducal seminal receptacle.

In addition to those characters mentioned previously, C. covacinae n. sp. differs further from its congeners in having the combination of an oral sucker, an oesophagus that is sinuous and that extends 59% of the body length, posterior caeca 3.9 times longer than the anterior pair, a testis width 55% of the body width, and a seminal vesicle positioned 13% of the body length from the posterior end and is 2.9 times longer than wide. It differs further in having an ovary that is positioned 24% of the body length from the posterior end, an oviducal seminal receptacle entirely posterior to the intercaecal field, a convoluted uterus that extends posteriorly from the oötype before looping anteriorly and male and female genital pores that open anterior to the oötype.

Figures

FIGURES 19–22. Cardicola covacinae. n. sp. from the bulbus arteriosus (heart) of Siganus punctatus off Heron Island. 19. Adult, whole mount, ventral view. Mehlis’ gland not seen in this specimen. 20. Anterior region, ventral view, showing vestigial oral sucker delimited by fine membrane. No spines seen on sucker due to very small size of specimen. 21. Male terminal genitalia, ventral view. 22. Female terminal genitalia, ventral view. Vitelline duct omitted from figure as it obscures the path of the uterus as it passes posteriorly. Scale­bars: 19, 250 m; 20, 200