Amphogona apsteini (Vanhoffen 1902)
- Dataset
- Hydromedusae observed during night dives in the Gulf Stream
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Cnidaria
- class
- Hydrozoa
- order
- Trachymedusae
- family
- Rhopalonematidae
- genus
- Amphogona
- species
- Amphogona apsteini
description
Fig. 59 A-B
discussion
Observations: Bell diameter 2 mm, flatter than hemisphere, jelly relatively thin especially towards margin; with thin gastric peduncle reaching almost to level of velum (Fig. 59 B); stomach small, lips inconspicuous. Eight radial canals. Gonads when fully developed ellipsoidal, pendant, close to ring canal, all of equal size or larger ones and smaller ones alternating; long axis of ellipsoidal gonads vertical (Fig. 59 A). About 70 tentacles, all the same structure. One to two statocysts per octant.
discussion
Remarks: Kramp (1959 a, 1965, 1968) states that the unequal size of the gonads, with small and larger ones alternating, is a characteristic trait of this species. However, this is found only in younger specimens, mature ones seem to have equally developed gonads (Bigelow, 1909; Nagata et al., 2014). Kramp gives also a bell size of 4 to 6 mm. Our specimens were smaller (2 mm). The type material was 2 to 3 mm in size, although perhaps not fully mature. Also Nagata et al. (2014) give a bell size of 2 to 3 mm.
distribution
Distribution: Circumglobal in warm waters. In the Indian Ocean from Indonesia to Moçambique (Kramp, 1953, 1968; Bouillon, 1978 a); in the Pacific Ocean from eastern Australia, to the northern Part of the China Sea and Peru (Kramp, 1953, 1965; Bouillon, 1978 c; Du et al., 2010; Oliveira et al., 2016). In the South Atlantic from Argentina to Brazil and to western Africa (Kramp, 1955 b; Nagata et al., 2014; Oliveira et al., 2016). In the North Atlantic reported from the mid Atlantic to Florida (Bleeker & Van der Spoel, 1988; Larson et al., 1991; this study). Type locality: Indian Ocean, west coast of Sumatra.
materials_examined
Examined material: BFLA; 1 specimen; 09 - DEC- 2019; size 2 mm, juvenile; preserved in alcohol for DNA extraction; 16 S sequence could not be obtained as PCR failed repeatedly. – 05 - JUL- 2019; 2 specimens photographed, 2 mm, not collected.
Name
- Homonyms
- Amphogona apsteini (Vanhoffen 1902)