Monostaechoides providentiae Gil & Ramil 2021, gen. et comb. nov.

• Main Authors: Gil, Marta, Ramil, Fran
• Format: Other/Unknown Material
• Language: unknown
• Published: 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Leptothecata; Halopterididae; Monostaechoides; Monostaechoides providentiae; South Atlantic Ocean
• Online Access: https://zenodo.org/record/5093692; https://doi.org/10.5281/zenodo.5093692

Monostaechoides providentiae (Jarvis, 1922) gen. et comb. nov. Figs 5–6, 7A–B; Table 11 Plumularia providentiae Jarvis, 1922: 347–348, pl. 26 fig. 21. Antennella quadriaurita – Millard 1966: 492–493. — Calder 1997: 27–29, fig. 6 (not Antennella quadriaurita Ritchie, 1909). Material examined SOUTH ATLANTIC OCEAN • 3 colonies, 19–23 mm high, on sponge (1 with gonothecae); Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40063, LZM-UV slide R. 576 • 4 colonies, 5–7 mm high (1 colony, growing on algae, with gonothecae); Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″– 8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40227, SEAFO-2015-40497, SEAFO-2015-40768, LZM-UV slide R. 581. Description Hydrorhiza composed of a cluster of perisarcal tubes covered by a sponge growing on old gorgonian axis. In some cases, isolated hydrocladia are born directly on the hydrorhiza but, in most cases, several monosiphonic primary hydrocladia arise in tufts from a short, polysiphonic axis composed by several entangled stolons protruding from the sponge. The basal part of the primary hydrocladium is composed of one to five internodes separated by straight nodes, provided with a variable number of scattered nematothecae separated from the remainder of hydrocladium by an oblique node. This part is formed by a regular succession of hydrothecate and ahydrothecate internodes, delimited by alternating oblique and straight nodes; hydrothecate internodes with proximally oblique and distally straight nodes; ahydrothecate internodes with a reversed position of nodes (Figs 5E, 6C, 7B). Almost all primary hydrocladia carry lateral ramifications randomly disposed, always originating from their posterior side. In most cases, the subsidiary hydrocladia arise from the distal end of ahydrothecate internodes, just on the back side of the oblique nodes within the heteromerous part of the colony (Fig. 6A); occasionally, some ramifications are found on ...