Plumularia sp.

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 : 46-48

Plumularia sp. Pictet, 1893

Fig. 20F

Description: Few fragmented colonies found, longer fragment 18.5 mm high. Stem monosiphonic, unbranched, divided into internodes separated by transverse nodes. Stem internodes carrying an apophysis distally and two nematothecae, one proximal axillar and another in the middle of the internode, and also with few internal septa in the proximal region. Apophysis long, with prominent internal septa, carrying one hydrocladium. Hydrocladia 1.5–12.6 mm high, formed by several intersegments, separated by transverse nodes. Hydrocladia intersegment with or without hydrothecae, alternately. First intersegment short, without hydrothecae or nematothecae and with internal septa. Other intersegments ahydrothecate, short, and sometimes with internal septa in the end and caring one nematotheca. The intersegments with hydrothecae carrying three nematothecae, one medial inferior and a pair of laterals, and also with internal septa in the end. Hydrothecae small, shallow, 74–95 µm high, 94–111 µm wide at the margin, cylindrical, adcaulinar wall convex, completely adnate to the hydrocladia, abcaulinar wall straight, margin smooth, aperture round. Medial inferior nematothecae short, not reaching the hydrothecal base. Lateral nematothecae inserted in the hydrocladia at the distal portion of the hydrothecae, surpassing the hydrothecal margin. Nematothecae of internodes similar to the medial inferior ones.

Material examined: PCS – two fragmented infertile colonies, one from the dry and the other from the rainy season. CZUFS CNI-00022; CNI-00198.

Stations: PCS – 5, 11.

Bottom: sand.

Taxonomic remarks: Besides the similarity between the specimens from Sergipe and the ones described as Plumularia strictocarpa by Calder (1997, p. 21-24), the colonies were unfertile and the gonotheca represents a crucial characteristic to distinguish P. strictocarpa from P. setacea (Linnaeus, 1758) . Because of this, we chose to let our material as Plumularia sp.

Remarks: unknown substrate.

Plumularia floridana Nutting, 1900 Fig. 20B

Synonyms available from: Calder (1997) and Galea (2008). Plumularia floridana Nutting, 1900: 59 , pl. 2, fig. 4, 5, – Migotto,

1996: 55, fig. 10D, F.

Description: Colonies erect, up to 33 mm high, arising from a creeping hydrorhiza. Stem monosiphonic, with or without ramifications, divided into one basal and one distal portion. The basal portion of the stem divided into regular internodes separated by regular transverse nodes, each internode carrying an apophysis distally and two or three nematothecae, one or two axillars, and one opposite to the apophysis. Apophysis short, arising alternately and carrying a hydrocladium. One or two ramifications arise from the same place in the hydrocladia or irregularly arranged, similarly to the primary stem. Hydrocladia 1038–2329 µm high, directed toward the outside, divided alternately into internodes with and without hydrothecae, separated by transverse nodes (proximally) and oblique ones (distally). Internodes without nematothecae or with a single one, and also with one hydrotheca carrying three nematothecae, a medial inferior, and a pair of laterals. Hydrothecae cylindrical, deep, 139–151 µm high, 123–136 µm wide, adnate to the stem along almost half of their length, with the distal portion free, abcauline and adcauline wall slightly convex basally and concave distally. Hydrothecal margin smooth, aperture oval. All nematothecae two-chambered and conical. Medial inferior nematothecae reaching (or almost) the base of the hydrothecae. Lateral nematothecae directed upward and do not reach the hydrothecal margin. Nematothecae in the internodes similar to the medial inferior ones but smaller. Hydranth retracted, with approximately 12 tentacles. Mature gonangia oval, 110–130 µm high, 102–110 µm in maximum width, arising from a short pedicel in the axis between the stem and the hydrocladia. Nematocysts euryteles discharged (23.3–32.7 × 10.1–12.3 µm).

Material examined: PCS – one infertile colony from the rainy season; VB – abundant colonies with and without mature gonangia from the dry and rainy seasons; SE – several colonies, one of them with mature gonangia, from the dry and rainy seasons. CZUFS CNI-00189; CNI-00190; CNI-00191; CNI-00192.

Stations: PCS – 5; VB – C1P12, C1P34, C1P56, C2P12, C2P34, C2P56, C3P34, C3P56; SE – C1P34, C1P56, C2P12, C2P56, C3P12, C3P34, C3P56.

Bottom: sand.

Distribuion: Brazil – Ceará ( Marques et al. 2006, Shimabukuro 2007), Pernambuco ( Calder and Maÿal 1998), Alagoas ( Shimabukuro 2007), Bahia (Kelmo et al. 2003), Espírito Santo ( Vannucci 1951a, Grohmann et al. 1997, 2003), Rio de Janeiro ( Vannucci Mendes 1946, Vannucci 1949, Miranda et al. 2015), São Paulo ( Vannucci Mendes 1946, Vannucci 1951a, Migotto 1996, Shimabukuro 2007, Silveira and Morandini 2011, Miranda et al. 2015), Paraná ( Cangussu et al. 2010, Maria A. Haddad unpub. data), and Santa Catarina ( Alaja-Batista et al. 2020). World distribution – records from the Atlantic (western and eastern), Indian, and Pacific Oceans ( Calder 1997).

Remarks: Unknown substrate to PCS material. Estuarine colonies were colonizing the plates, algae, Anthozoa ( Carijoa sp. ), Bryozoa, barnacle (Cirripedia), Polychaeta tubes, Ostreidae, Ascidiacea , and the hydroids Bougainvillia muscus , Corydendrium parasiticum , Diphasia digitalis , Ectopleura dumortierii , Eudendrium merulum , and Pennaria disticha .

Figures

Figure 20. (A) Dentitheca bidentata: detail of a stem with few hydrocladia and one male gonotheca; (B) Plumularia floridana: detail of a stem showing several hydrothecae and mature gonangia (red arrows); (C) Monotheca margaretta: detail of a stem with few hydrothecae and one gonotheca; (D-E) Monotheca obliqua: (D) general view of a stem; (E) detail of a hydrotheca; (F) Plumularia sp.: (F) detail of a stem showing several hydrocladia and hydrothecae.