Fig. 59 A-B
Pantachogon apsteini Vanhöffen, 1902: 65, pl. 10 fig. 18, pl. 11 fig. 28.
Amphogona apsteini. ‒ Browne, 1905: 740, pl. 54 fig. 5, pl. 56 fig. 1, pl. 57 figs 10-15. ‒ Bigelow, 1909: 126, pl. 2 figs 1-2, pl. 34 figs 12-15, pl. 45 fig. 10. ‒ Mayer, 1910: 405, fig. 257. ‒ Kramp, 1959a: 188, fig. 280. ‒ Kramp, 1965: 123, figs 12-13. ‒ Kramp, 1968: 118, fig. 319. ‒ Bleeker & Van der Spoel, 1988: 241, fig. 37.
Examined material: BFLA; 1 specimen; 09-DEC- 2019; size 2 mm, juvenile; preserved in alcohol for DNA extraction; 16S sequence could not be obtained as PCR failed repeatedly. – 05-JUL-2019; 2 specimens photographed, 2 mm, not collected.
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. 59B); 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. 59A). About 70 tentacles, all the same structure. One to two statocysts per octant.
Distribution: Circumglobal in warm waters. In the Indian Ocean from Indonesia to Moçambique (Kramp, 1953, 1968; Bouillon, 1978a); in the Pacific Ocean from eastern Australia, to the northern Part of the China Sea and Peru (Kramp, 1953, 1965; Bouillon, 1978c; Du et al., 2010; Oliveira et al., 2016). In the South Atlantic from Argentina to Brazil and to western Africa (Kramp, 1955b; 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.
Remarks: Kramp (1959a, 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.