Eirenida Maronna, Miranda, Peña Cantero, Barbeitos and Marques, 2016

Castro Mendonça, Luana M., Parisotto Guimarães, Carmen R. & Haddad, Maria A., 2022, Taxonomy and diversity of hydroids (Cnidaria: Hydrozoa) of Sergipe, Northeast Brazil, Zoologia (e 21032) 39, pp. 1-65 : 26

Suborder Eirenida Maronna, Miranda, Peña Cantero, Barbeitos and Marques, 2016 Lovenellidae Russell, 1953

Mitrocomium cirratum Haeckel, 1879 Fig. 12A–B

Synonyms available from: Calder (1991). Mitrocomium cirratum Haeckel, 1879: 182 , pl. 11, figs 9-11 [medusa]. Lovenella cirrata – Vannucci, 1957: 60 [medusa].

Description: Colonies stolonal, up to 664 µm high, with several pedicels of variable length arising from a creeping hydrorhiza. Perisarc thin and smooth. Pedicel supporting a primary hydrotheca. Hydrothecae shallow, 317–649 µm high, 96-107 µm wide, rarely with renovations in the estuarine material and frequent ones in the PCS material. Secondary hydrothecae, arising inside the primary from pedicel of variable length. Margin entire, diaphragm distinct, large desmocytes present in a ring between diaphragm and margin. Hydranths of variable length, with a whorl of approximately 12 tentacles. Nematocysts mastigophores heteronemes? undischarged (29.4–35 × 8.8–11.2 µm).

Material examined: PCS – three infertile colonies from the dry and rainy seasons; VB – few infertile colonies from the dry and rainy seasons. CZUFS CNI-00056; CNI-00135; CNI-00136; CNI-00137; CNI-00138.

Stations: PCS – 9; VB – C1P34, C1P56, C2P34, C2P56, C3P34, C3P56.

Bottom: mud.

Distribution: Brazil – the only Brazilian record for the polyp stage is from São Paulo ( Fernandez et al. 2015). Migotto et al. (2002, as Lovenella cirrata (Haeckel, 1879)) mentioned the records for the medusa from Pará ( Thiel 1938), São Paulo, and Paraná ( Vannucci 1957). There is also a record of the medusa stage in Santa Catarina ( Nogueira-Junior et al. 2015). World distribution – records from Atlantic (eastern and western), Indian, and Pacific Oceans ( Calder 1991).

Remarks: Colonizing the plate, Bryozoa, Ostreidae, Ascidiacea , and the hydroids Bimeria vestita , Obelia oxydentata , and Pennaria disticha .

Figures

Figure 12. (A-B) Mitrocomium cirratum: (A) general view of a colony; (B) detail of the proximal region of a polyp showing some nematocysts; (C-F) Nemalecium lighti: (C) general view of a stem showing a gonotheca (red arrow); (D) detail of a colony highlighting a hydranth with a pair of nematodactyls (red arrows); (E) detail of a colony with hydranths; (F) detail of the stem showing a gonotheca.