Virididentula dentata ( Lamouroux, 1816 ) Unassigned

Ruiz-Velasco, Sofía, Ros, Macarena, Guerra-García, José M. & López-Fé, Carlos M., 2025, Fouling bryozoans in recreational marinas of the Canary Islands (North-Eastern Atlantic) with new records of non-indigenous and cryptogenic species, Zootaxa 5656 (1), pp. 1-63 : 20-22

Virididentula dentata ( Lamouroux, 1816) Unassigned

( Fig. 8 ; Table 8)

Acamarchis dentata Lamouroux, 1816: 135 , pl. 3, fig. 3A, B.

Bugula dentata : Busk 1852: 46, pl. 35, figs 1–5; Norman 1909: 285, pl. 36, fig. 3; Ramalho et al. 2005: 239, fig. 6; Florence et al. 2007: 17, figs 5E–F, 20B, 21L.

Virididentula dentata : Fehlauer et al. 2015: 9, fig. S4; Ramalhosa et al. 2017: 8, fig. 4.

Figured material. Morro Jable (27/06/23) (2C on rope) ( MNCN 25.03/4456).

Other material examined. Las Galletas (19/06/23) (2C on floating pontoon), Gran Tarajal (28/06/23) (1C on floating pontoon).

Description. Colonies greenish, erect and branching, forming small tuffs ( Fig. 8A ). Branches with biserial pattern. Zooids elongate and rectangular, slightly narrower in the proximal portion ( Fig. 8B ). Frontal membrane with proximal U-shaped edge, occupying around two-thirds of the frontal area of the zooid. Outer distal margin with three spines (the middle one the longest), and inner distal margin with one spine ( Fig. 8C ). Avicularia pedunculate and aquiline shaped, located near the proximal third of the outer margin ( Fig. 8C ). Beak of the rostrum hooked rectangularly and distally pointed ( Fig. 8D ). Ooecia globular, directed slightly towards the inside ( Fig. 8E ).

Remarks. Virididentula dentata shows divergent lineages according to COI sequences and a high intraspecific morphological variation ( Mackie et al. 2002). Therefore, nowadays it is considered a species complex ( Micael et al. 2016). This morphological variation is observed in: (1) the position of the avicularium, which is medially located in specimens from Heron Island (Ryland 1974) but closer to the base of the autozooid in material from Victoria ( Australia), New Zealand ( Mackie et al. 2002), Brazil ( Ramalho et al. 2005), and Macaronesia ( Ramalhosa et al. 2017; present study); (2) in the presence of giant avicularia, reported in specimens from Hawaii ( Mackie et al. 2002); and (3) in the orientation of the ooecia, which are directed inwards in material from Hawaii ( Mackie et al. 2002), the Celebes Sea (Harmer 1926), and Macaronesia ( Ramalhosa et al. 2017; present study), but horizontally oriented in material from southern Australia and New Zealand ( Mackie et al. 2002). Our V. dentata specimens closely resemble material from Ramalhosa et al. (2017) from Madeira, with avicularia located closer to the base of the zooidal frontal membrane, absence of giant avicularia and the ooecia directed inwards.

Distribution and status. Virididentula dentata shows a pan temperate-tropical distribution ( Mackie et al. 2002), with reports from the Indo-Pacific (Australia-New Guinea continent, Japan, Hawaii, the Celebes Sea), which has been suggested as its potential area of origin ( Norman 1909; Canning-Clode et al. 2013a) and from the Atlantic Ocean in Brazil, South Africa, Cape Verde, the Azores, Madeira, and the Canary Islands ( Ramalho et al. 2005; Ramalho 2006; Florence et al. 2007; Mead et al. 2011; Micael et al. 2016; Ramalho et al. 2021). Although this species complex has been reported in Madeira and Cape Verde since the beginning of the 20 th centhury ( Norman 1909), its presence is relatively new to other Macaronesian archipelagos. For example, its first detection in the Azores was in 1997 ( Cardigos et al. 2006). In the case of the Canary Islands, it likely established several decades ago (detected in 1993), in both artificial and natural habitats ( Moro et al. 2018). Virididentula dentata has been considered cryptogenic in Macaronesia ( Cardigos et al. 2006; Micael et al. 2019; AquaNIS 2024) due to its wide distribution and, therefore, the uncertainty of its native geographical distribution. Nevertheless, it must be noted that Norman (1909) mentioned that this species was only previously known to the Indo-Pacific and South Africa, where its early introduction has been suggested ( Mead et al. 2011). Despite these suggestions, in view of the taxonomic uncertainty of this species complex, we consider it as unassigned in the Canary Islands.

Figures

FIGURE 8. Virididentula dentata (Lamoroux, 1816) (MNCN 25.03/4456). A. Live specimen. B. View of the colony through SEM. C. Detail of outer and inner spines. D. Avicularium. E. Branch including ovicelled zooids through stereomicroscope. Scale bars: A = 2 cm; B = 400 µm; C = 100 µm; D = 20 µm; E = 200 µm.