Campanularia laminocarpa Millard, 1966

Watson, Jeanette E., 2016, Two new species and a new record of hydroids (hydrozoa: hydroidolina) from Port Phillip, Australia, Memoirs of Museum Victoria 75, pp. 1-5 : 4

Campanularia laminocarpa Millard, 1966

Figure 3A-E

Campanularia laminocarpa Millard, 1966: 211 , fig. 67F-K Clytia sp. Watson 1975: 158 , fig. 1.

Material examined. Microslide NMV F228244, malinol mounted, from small infertile colony epizoic on Sertularella eleganta in crevice, 1m deep, coll: J.E.Watson, 22/3/2016. Other Material: NMV F228246 microslide, malinol mounted, fertile colony on Synthecium patulum ( Busk, 1852) on reef, North Arm Channel Western Port, 8m, coll: J.E. Watson 16/12/1996. NMV F228247 microslide, malinol mounted, fertile colony on Synthecium patulum , reef, 2 km offshore from McGaurans Beach, Ninety Mile Beach, Bass Strait, 16m, coll: J.E. Watson 12/8/1983. Microslide (author’s collection), malinol mounted, Fluted Cape, Tasmania, 15m deep, coll: J.E.Watson, April, 1975.

Description. Colony (NMV F228244) stolonal, hydrorhizal stolon tubular, reptant on Sertularella eleganta . Hydrocaulus pedicellate, unbranched, monosiphonic, pedicels variable in length and width, deeply annulated or spirally ringed throughout, rarely with smooth patches, pedicel terminating in a cushion-shaped shoulder supporting a spherule. Hydrotheca proximally narrow with a moderately long subhydrothecal chamber with shallow perisarcal distal ring, walls then widening to become parallel, sometimes expanding, circular in section. Margin not everted, with 8-10 long cusps separated by moderately deep and wide embayments, a slight thickening of perisarc below margin.

Gonothecae male [Western Port (NMV F228246) and Bass Strait (NMV F228247)], very large, campanulate, flattened, borne from hydrorhiza on a short unsegmented pedicel, held obliquely away from host, perisarc smooth without ornamentation, aperture occupying entire distal margin, sealed by a thin dome-shaped operculum torn aside at maturity. Perisarc thin and transparent throughout, gonotheca fragile and easily collapsed.

Remarks. I have compared several specimens of Campanularia epizoic on Synthecium patulum ( Busk, 1852) collected over many years of scuba diving from the southern Australian localities of Western Port, Bass Strait and Tasmania with a specimen Campanularia laminocarpa Millard, 1966 (gift to author from Millard in 1985). Although the size, shape and dentition of the hydrotheca varies within Australian localities, morphology and dimensions of the gonothecae clearly establishes the Australian material as C. laminocarpa . Minor morphological differences between the South African and Australian material such as hydrothecal marginal replication of the South African species replaced by submarginal thickening in the Australian material may be due to environmental factors or colony maturity. The weak perisarcal thickening at the junction of the subhydrothecal chamber with the body, commented upon by Millard (1966), is present in some Australian hydrothecae and can be mistaken for a diaphragm (see Watson 1975: 158). The hydrothecal margins of the present specimens of C. laminocarpa are very fragile and easily collapsed, resulting in changes in apparent shape of the cusps in mounted specimens.

The small infertile colony on branches of the Sertularella eleganta host is intergrown with Clytia hemisphaerica .