Macrorynchia fallax, Galea & Maggioni, 2024

Galea, Horia R. & Maggioni, Davide, 2024, On some tropical hydroids (Cnidaria: Hydrozoa), with descriptions of four new species, Zootaxa 5428 (1), pp. 1-57 : 47-48

Leptothecata : Aglaopheniidae

A total of 11 aglaopheniid species from Bali were sequenced, including Aglaophenia postdentata ( Billard, 1913) , Gymnangium hians ( Busk, 1852) , G. sibogae ( Billard, 1913) , Lytocarpia brevirostris ( Busk, 1852) , L. delicatula ( Busk, 1852) , L. phyteuma ( Stechow, 1919b) , Macrorynchia fallax sp. nov., M. phoenicea ( Busk, 1852) , M. spectabilis ( Allman, 1883) , Monoserius pennarius ( Linnaeus, 1758) and Taxella eximia Allman, 1874 . Specifically, genetic data for M. spectabilis are available for the first time, supplementing those obtained earlier for G. hians , G. sibogae and M. pennarius (P. Schuchert, unpublished data). Interestingly, L. brevirostris from Bali shows a high 16S rRNA genetic distance (of 9.2 ± 1.2%) with a sequence from Madagascar, despite forming, altogether, a monophyletic group, possibly suggesting the presence of cryptic species ( Fig. 33 ). Similarly, T. eximia from Bali clusters with other Taxella species ( Fig. 33 ), being nevertheless divergent from a sequence of T. eximia from the Western Indian Ocean (16S rRNA genetic distance of 7.5 ± 1.2%).

The 16S rRNA region of M. fallax could not be amplified, despite several attempts, while other regions were successfully amplified and sequenced (COI, 18S rRNA, and 28S rRNA). Specifically, a phylogenetic hypothesis based on the COI region was obtained to assess the relationships between M. fallax and other aglaopheniid species ( Fig. 34 ). The two COI sequences obtained for M. fallax are identical to each other and closely related to sequences obtained from M. philippina Kirchenpauer, 1872 and M. filamentosa ( Lamarck, 1816) . However, they show high genetic distances from these two species, viz. 9.9 ± 1.2% and 11.1 ± 1.2%, respectively.

Figures

FIGURE 33. Phylogenetic hypothesis of the family Aglaopheniidae based on the 16S rRNA region. Numbers at nodes represent BPP and MLBS, respectively.

FIGURE 34. Phylogenetic hypothesis of the family Aglaopheniidae based on the COI region. Numbers at nodes represent BPP and MLBS, respectively.