Polydorella stolonifera ( Blake and Kudenov, 1978 )
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publication ID |
https://doi.org/ 10.1080/0022293031000155395 |
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persistent identifier |
https://treatment.plazi.org/id/537A7F7A-FF9E-FD31-551B-9B49706EFB2A |
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treatment provided by |
Felipe |
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scientific name |
Polydorella stolonifera ( Blake and Kudenov, 1978 ) |
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Polydorella stolonifera ( Blake and Kudenov, 1978) View in CoL
( figures 6 View FIG , 8 View FIG )
Polydorella stolonifera ( Blake and Kudenov, 1978) View in CoL : 269–271, figure 50a–j.
Material examined. Twelve paratypes from Australia, Victoria, Westernport Bay, Crawfish Rock , 5 m, 3 January 1972, from Ancorina cordicata (Carter, 1879) ( NMV F42898 View Materials , previously registered as G2898; two prepared for SEM) .
Description
Largest single individual 3.8 mm long and 0.6 mm wide at segment 7; 16 segments, with endoparasitic copepod (see Remarks); single individuals with developing growth zone of stolon 1 and 16 segments 2.5 mm long and 0.4 mm wide at segment 7 ( figure 8A View FIG ). Prostomium bifid; caruncle short, terminating at posterior margin of segment 1; occipital tentacle and eyes absent ( figure 8A, B View FIG ). Palps extend posteriorly for 8–12 segments. Pigmentation absent.
Segment 1 with small notopodial lobe without notosetae; neuropodial lobe with two or three winged capillary neurosetae ( figure 8A, B View FIG ). Unilimbate capillary notosetae of segments 2–4, 6 and subsequent segments in two rows. Unilimbate capillary neurosetae of segments 2–4, 6 and 7 arranged in two rows; up to eight bidentate hooded hooks begin on segment 8, not accompanied by capillaries ( figure 8A, B View FIG ); hooks with approximately right angle between main fang and shaft, narrow angle between main fang and apical tooth, with constriction on shaft.
Segment 5 slightly modified, about the same size as segments 4 and 6, with
posteroventral fascicle of bilimbate capillary neurosetae in two rows; notosetae absent. Two types of major spines of segment 5 in approximately horizontal curved row; ventral row of three to six spines with expanded tips covered by fine bristles and a dorsal row of up to five simple acicular spines ( figure 6G View FIG ).
Branchiae present on segments 7 and 8 ( figure 8A, B View FIG ). Dorsal ciliary bands from segment 2 continuing to terminal segments ( figure 8B View FIG ).
Pygidium with small cirri surrounding terminal anus ( figure 8A View FIG ).
Asexual reproduction and parasitism
Of 12 individuals examined, 10 exhibited asexual reproduction with two individuals joined in a chain ( figure 8A View FIG ). The two single individuals consisted of up to 16 segments; both possessed endoparasitic copepods within segments 8–12. Individuals undergoing asexual reproduction contain a growth zone that developed after segment 10. Formation of new posterior stock segments is apparent in side and ventral views ( figure 8A View FIG ). The sequence of stolon body formation appears to be similar to that described for Polydorella kamakamai , although no specimens were composed of more than two individuals.
Distribution South China Sea: south-eastern coast of Vietnam, Philippines; Red Sea.
Remarks
Blake and Kudenov (1978) indicated that brown pigmentation was present on the branchiae, peristomium and sides of anterior segments; this pigmentation has been lost from the specimens stored in alcohol for 29 years. This is the first report of parasitic copepods within Polydorella stolonifera , although Radashevsky (1996) noted such parasites in P. dawydoffi . The copepod parasites apparently interfere with the process of asexual reproduction in Polydorella . These parasites may induce larger numbers of segments and longer length in infected individuals; 16 segments in P. stolonifera that contained parasites versus 15 segments in those lacking parasites and 17–18 segments in parasitized P. dawydoffi versus 15 segments in those lacking parasites. The present findings are in contrast to those of McCurdy (2001), who found earlier fragmentation in asexual reproduction via architomy by Pygospio elegans Claparède, 1863 when parasitized by trematode metacercariae. Such differences are not unexpected because host responses to parasites could be influenced by a variety of factors including mode of asexual reproduction (i.e. paratomy versus architomy) and type of parasite (crustacean versus trematode).
| NMV |
Museum Victoria |
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