Protula balboensis Monro, 1933

Rodrigues, Andrielle Raposo, Skinner, Luis Felipe & Brasil, Ana Claudia dos Santos, 2020, Do Morphological Similarities and human-induced dispersal explain the non-native occurrence of Serpulidae (Annelida) in Southwest Atlantic? Taxonomic detailing is the key, Papéis Avulsos de Zoologia 60, pp. 1-15 : 8-11

Genus Protula Risso, 1826 Protula balboensis Monro, 1933

( Figs. 7 and 8 )

Protula tubularia balboensis Monro, 1933: p. 1088 -1090; text-figure 30, A-D.

Protula balboensis: Zibrowius, 1970: p. 17 -18; pl. 4; fig. 9; Bastida-Zavala, 2008: p. 37 ; fig. 8H; Bastida-Zavala et al., 2017: p. 42-43 ; figs. 7B-E, 8.

Examined material: 28 specimens. Rio de Janeiro State, Mangaratiba Municipality: Ilha da Madeira: Praia do Sino: 23°05′01.7″S, 44°00′27.9″W, MNRJP2187 (22 specimens) . Praia de Ibicuí: 22°57′45.3″S, 44°01′28.5″W (3 specimens) . Ilha de Itacuruçá : 22°56′58.6″S, 43°53′13.4″W

(2 specimens). Ilha Guaíba : 23°00′13.1″S, 44°03′07.9″W (1 specimen) .

Description (based on 10 individuals collected from

Marambaia Island)

Tube: Externally, white and rugose, inside white ( Fig. 7C ); circular in cross-section.Without longitudinal ridge, alveoli and peristomes.Attached to rocky shores of intertidal zone.

Radiolar crown: Radioles arranged in semi-circles with 18-20 radioles per lobe ( Fig. 7A ). External side smooth, internal side with two rows of pinnules.Terminal filament without pinnules. Inter-radiolar membrane ⅓ of radioles length, with rounded processes at end of membrane ( Fig. 7B ). Stylodes absent. Eyespots present, pigmented with red or yellow colours. Colour base in live animals a mixture of orange/yellow pigments, in fixed animals a light yellow.

Peduncle: Absent.

Operculum: Absent.

Collar and thoracic membranes: Trilobed, well-developed, reddish thoracic membrane in live, subdivided into one mid-ventral and two lateral lobes, the same size ( Fig. 7A ). Tonguelet absent. Latero-dorsal lobes continuing in thoracic membranes well-developed producing a

short ventral apron. Collar chaetae of only one type: limbate ( Fig. 8A ).

Thorax: Seven chaetigers, including five uncinigerous; collar fascicle without row of uncini. Second chaetiger with chaetae limbate, without uncini. Chaetae limbate of 2 sizes ( Fig. 8B ). Uncini rasp-shaped teeth including peg; peg (anterior-most tooth) gouge shaped. Apomatus chaetae absent.

Abdomen: Total number of chaetigers varies from 26 to 42 (mean = 37; SD = 5.7; n = 10). Anterior and mid-abdominal chaetigers, chaetae geniculate ( Fig. 8C ); abdominal uncini similar to thoracic uncini. Posterior chaetigers with capillary chaetae.

Measurements: Total lenght: mean = 4.2 (SD = 1.4; n = 10); Thoracic lenght: mean = 1.4 (SD = 0.45 [n = 10]); Thoracic width: mean = 0.54 (SD = 0.16; n = 10). Abdominal lenght: mean = 2.2 (SD = 0.87; n = 10).

Remarks: Twenty-three species of Protula are known from across the globe ( ten Hove & Kupriyanova, 2009), of which only three have been recorded from the Brazilian coast: P. tubularia ( Montagu, 1803) , P. submedia Augener, 1906 , and P.balboensis (Amaral et al., 2013; Pagliosa et al., 2014).

Protula tubularia and P. balboensis are similar in having limbate thoracic chaetae and geniculate abdominal chaetae. Protula balboensis has interradiolar processes on the external face of the radiolar membrane and a rugose tube, whereas P. tubularia lacks interradiolar processes and its tube is smooth (i.e., without ridges, peristomes or alveoli) ( Monro, 1933; Zibrowius, 1970).

Protula submedia and P. balboensis are quite distinct. Protula submedia produces a tube showing growth lines with peristomes in the anterior section,the number of radioles varies between 25-50, and their abdominal chaetae are straight ( Zibrowius, 1970). In contrast, P. balboensis produces a rugose tube (without ridges, peristomes or alveoli), has from 18 to 20 radioles per lobe in large individuals, and its abdominal chaetae are geniculate.

Our specimens have rugose tubes, lacking ridges, peristomes or alveoli, membrane processes are present, the collar and thoracic chaetae are limbate but the abdominal chaetae are geniculate/sickle-shaped. Protula balboensis was described from Balboa on the Pacific coast of Panama. In Brazil, the species was recorded previously at Recife da Lixa, Bahia State, Brazil and, here, we present the first record of this species from Rio de Janeiro State, Sepetiba Bay, in southeastern Brazil.

Habitat: The specimens were found attached to rocks of the intertidal zone and attached under Phragmatopoma sp. aggregate.

Type-locality: Balboa, Pacific Panama.

Distribution: West Pacific Ocean: Japan ( Uchida, 1978); West Atlantic Ocean, United States: Jacksonville; Florida; Biscayne Bay, Florida; and Corpus Christi, Texas (Bastida- Zavala et al., 2017); Gulf of California ( Bastida-Zavala, 2008); Pacific Ocean: Mexico (Bastida-Zavala et al., 2016), Acapulco ( Bastida-Zavala, 2008), Taboga Island, Panama and Gorgona Island (Bastida-Zavala et al., 2016); Colombia ( Monro, 1933); Atlantic Ocean: Bocas Del Toro (Bastida-Zavala et al., 2016), Atlantic Panama (Bastida- Zavala et al., 2016); West Atlantic Ocean, Brazil: Bahia ( Zibrowius, 1970) and Rio de Janeiro, Sepetiba Bay (current work).

Figures

Figure 7. Protula balboensis. (A) Complete body,lateral view;(B) Branchial crown;(C)Tube with a worm inside.Scale bars:Aand C:2 mm;B:500 µm.

Figure 8. Protula balboensis, types of chaetae.(A) Collar chaetae;limbate chaetae;(B) Thoracic chaetae;limbate chaetae;(C) Abdominal chaetae;geniculate chaetae.Scale bars:A-C:500 µm.