Waminoa brickneri, Ogunlana & Hooge & Tekle & Benayahu & Barneah & Tyler, 2005
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publication ID |
https://doi.org/ 10.11646/zootaxa.1008.1.1 |
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publication LSID |
lsid:zoobank.org:pub:73DD7314-AF47-4810-91B9-6EDA9903E37E |
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persistent identifier |
https://treatment.plazi.org/id/F37B87C6-FF9B-E403-2676-FC4FEBF4E058 |
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treatment provided by |
Felipe |
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scientific name |
Waminoa brickneri |
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sp. nov. |
Waminoa brickneri View in CoL sp. nov. ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )
Type Material. Holotype ( ZMTAU VR 25067 ): epoxyembedded specimen sagittally sectioned into 2µmthick sections stained with toluidine blue . Paratype ( ZMTAU VR 25068 ): epoxyembedded specimen sagittally sectioned into 2µmthick sections stained with toluidine blue .
Type Repository. Zoological Museum, Tel Aviv University , Israel .
Type Locality. Eilat , Israel, near the oil jetties (34.93° N, 29.52° E) from the coral Plesiastrea laxa , 21 March 2004 GoogleMaps .
Other Material Observed. Serial toluidinebluestained sagittal sections of 4 epoxyembedded sexually mature specimens and 3 immature specimens collected by O. B. on 21 March, 2004, and 3 June, 2003, from Plesiastrea laxa and Stereonephthya cundabiluensis , respectively.
Etymology. Species named for Dr. Itzchak Brickner who discovered it and its symbiosis with corals.
Description. Waminoa brickneri is a flat, discshaped acoel, 3–4 mm in diameter and 1 mm thick, found closely appressed to the external surfaces of stony and soft corals ( Fig. 1A View FIGURE 1 ). It occurred in groups of nonoverlapping individuals causing the corals it infested, especially lightly colored ones, to appear spotted. The body was circular in profile except for a small medial notch at the posterior margin where the reproductive organs lay. The animal appeared bronzecolored with small white speckles, deriving its coloration from abundant dinoflagellate endosymbionts and scattered white pigment spots. Fixed specimens were more ovate in shape ( Fig. 1B View FIGURE 1 ), narrowed at the anterior end and broader posteriorly, measuring 2.2–3.2 mm long, and lacked the pigment spots.
Two types of endosymbionts were harbored in the parenchyma—a more abundant smaller type measuring about 4–8 µm and a larger type measuring about 11–16 µm ( Fig. 1C View FIGURE 1 ). Both types of endosymbionts lay scattered throughout the parenchyma and both were clearly identifiable as dinoflagellates by their permanently condensed chromosomes. By differences in the pyrenoid and by comparison with symbionts in W. litus and other acoel species, the smaller type appeared to be a species of Symbiodinium , while the larger one appeared Amphidinium like ( Barneah et al. 2004).
The epidermis was generally transparent, fully ciliated, and richly glandular ( Fig. 2B,C View FIGURE 2 ; 3A View FIGURE 3 ). Especially abundant were rhabdoid glands in the dorsal body wall and lateral sides. Like rhabdoid glands in other acoels, these glands had narrowed apices that gave them a toothlike appearance in sectioned material, and their rhabdiform secretory granules appeared striate. The ventral body wall was dominated by mucous glands having more amorphous secretory bodies; these mucous glands also occurred scattered in the dorsal body wall, but no rhabdoid glands occurred on the ventral side. Both rhabdoid and mucous glands stained metachromatically with toluidine blue, indicating presence of glycosaminoglycans; the mucous glands stained more darkly red, indicating more acidic polysaccharides. A third type of gland appeared to be a serous gland containing small spherical secretion granules staining dark blue with toluidine blue. It occurred sparsely scattered in both the dorsal and ventral body walls and more abundantly supraterminally at the anterior end; glands concentrated around the male gonopore appeared to be of the same type ( Fig. 3C View FIGURE 3 ).
The mouth was ventral in the posterior third of the body length. The digestive syncytium contained no recognizable contents—specifically, no nematocysts, which would indicate feeding on the coral tissues, could be found.
Although we found freshly hatched juveniles with a statocyst and paired eyes ( Fig. 1C View FIGURE 1 ), mature specimens of W. brickneri appeared to lack both. Also lacking was a frontal organ. The brain appeared to be bilobed and lay insunk just under the epidermis close behind the anterior tip of the body ( Fig. 2 View FIGURE 2 ); the two main masses consisted of central neuropile and nucleated rind and were connected by a short medial commissure. Behind it a short distance was a globular mass of unknown function consisting of closepacked, palely staining spherical cells with large nuclei.
The copulatory organs produced a slightly thickened ridge medially in the terminal quarter of the body ( Fig. 1A View FIGURE 1 ). The seminal vesicle was most prominent, appearing white from contained sperm, and lay just in front of the posterior notch in the body margin. The seminal bursa, though unpigmented, continued the ridge anterior of the seminal vesicle, and the mouth and central digestive syncytium continued it anterior of that toward midbody.
The paired ovaries extended from about the second quarter of the body length posteriorly behind the mouth and were ventrally situated ( Fig. 2 View FIGURE 2 ). The vagina was ciliated and opened on the ventral body wall immediately anterior to the male gonopore ( Fig. 3A View FIGURE 3 ). It led to a seminal bursa consisting of an illdefined syncytial mass with scattered and clumped sperm; extending from the lateral and anterior edges of the bursa were multiple sclerotized bursal nozzles. We could identify at least 4 of these small (3 µm diameter, 12 µm length) nozzles in sections of one specimen and at least 8 each in sections of two other specimens.
Paired testes lay dorsal and lateral to the ovaries ( Fig. 2 View FIGURE 2 ), and led posteriorly to the seminal vesicle. The seminal vesicle was walled by thin, loosely concentric muscles and reached to an indistinct penis papilla ( Fig. 3 View FIGURE 3 ). The center of the seminal vesicle in all specimens contained a mass of lightstaining tissue interpreted as penis glands. Darkstaining, smallgranuled serous glands surrounded the male gonopore. Flanking the seminal vesicle were prominent false seminal vesicles continuous with the tracts of sperm descending from the testes ( Fig. 2 View FIGURE 2 ).
The partial 18S rDNA sequence of Waminoa brickneri , which we deposited in Gen Bank under accession number AJ875221 View Materials , emerged as most closely related to “Acoel sp. strain Asp2” (AJ012526) and “Acoel sp. strain Asp3” (AJ012525) in a BLAST search of GenBank sequences. These two acoel species are described there as being supplied by the Coral Reef Research Foundation, Palau, and the latter one specifically as a “striped acoel, found on Porites coral.”
Preliminary analysis of sequence data (unpublished) showed the sequence of W. brickneri to group most closely to sequences of members of the family Convolutidae (e.g., Amphiscolops sp. ), not the Haploposthiidae in which Waminoa is currently classified.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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