Leptomedusa sp. A

Verhaegen, Gerlien, Cimoli, Emiliano & Lindsay, Dhugal, 2021, Life beneath the ice: jellyfish and ctenophores from the Ross Sea, Antarctica, with an image-based training set for machine learning, Biodiversity Data Journal 9, pp. 69374-69374 : 69374

Leptomedusa sp. A

Materials

Type status: Other material. Occurrence : individualID: MCMEC2019_ Leptomedusa _sp_A_a; lifeStage: adult; associatedMedia: http://morphobank.org/permalink/?P3993; Taxon : kingdom: Animalia ; phylum: Cnidaria ; class: Hydrozoa ; order: Leptomedusae ; Location: continent: Antarctica; waterBody: McMurdo Sound; maximumDepthInMeters: 1; decimalLatitude: -77.637; decimalLongitude: 166.401; Identification: identifiedBy: Dhugal Lindsay; Event: samplingProtocol: Sony Alpha 7 III camera equipped with a FE 90mm F2.8 Macro G OSS lens; eventDate: 2019-11-14; Record Level: type: StillImage; language: en; rightsHolder: Emiliano Cimoli

Notes

Description of and comments on observed material: N = 1 in 2019 (Fig. 5 ). Although it is hard to tell whether the medusa is bell-shaped or actually flattened but contracted, the “gonads” confined to the radial canals indicate that the observed specimen likely belongs to the order Leptothecata (or the accepted alternative synonym " Leptomedusae ") ( Bouillon et al. 2006). The presence of one manubrium excludes the family Sugiuridae and the gonads not extending on the manubrium excludes the family Tiarannidae . Four radial canals, gonads thin and located midway along the radial canals, four tentacle bulbs located perradially on the rim of the bell, one short tentacle per tentacle bulb, with nematocysts concentrated in tentacle's distal tip, medusa transparent, except for white-yellow gonads and manubrium. Diagnostic characters that could not been verified for further classification of the medusa: shape of manubrium, statocysts, cordyli, ocelli, gastric peduncle, tentacle bulbs and tentacular expansions. This medusa morphotype does not appear in the list of Larson and Harbison (1990) for medusae reported from the Ross Sea and we could not identify any other described species with the same morphological characteristics in the wider literature.

Figures

Figure 5. Leptomedusa species A (specimen MCMEC 2019 _ Leptomedusa _ sp _ A _ a) observed on 14 / 11 / 2019: oral-lateral view. Photo courtesy: E. Cimoli.