Spirobranchus tetraceros ( Schmarda, 1861 )

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 : 2-6

publication ID

https://doi.org/ 10.11606/1807-0205/2020.60.05

DOI

https://doi.org/10.5281/zenodo.3728647

persistent identifier

https://treatment.plazi.org/id/03B39F1B-FF8C-0708-FCC3-F8BEFD83FD34

treatment provided by

Carolina

scientific name

Spirobranchus tetraceros ( Schmarda, 1861 )
status

 

Spirobranchus tetraceros ( Schmarda, 1861)   ( Figs. 2-4 View Figure 2 View Figure 3 View Figure 4 )

Pomatoceros tetraceros Schmarda, 1861: p. 30   ; Taf. XXI, fig. 179.

Spirobranchus tetraceros: ten Hove, 1970: p. 3-14   ; figs.1-6; 7-14; 15-22; 23-27. Ben-Eliahu & ten Hove, 2011: p. 88-94 View Cited Treatment ; fig. 33A-E; table 5. Kupriyanova et al., 2015: p. 337-339 View Cited Treatment ; fig. 30C-D.

Examined material: 199 specimens. Rio de Janeiro State, Mangaratiba Municipality: Ilha de Itacuruçá : 22°56′58.6″S, 43°53′13.4″W, MNRJP2184 (105 specimens) GoogleMaps   . Ilha dos Martins : 22°57′17.0″S, 43°51′39.2″W (3 specimens) GoogleMaps   . Ilha de Jaguanum : 23°00′08.8″S, 43°56′14.4″W (6 specimens) GoogleMaps   . Ilha Guaíba : 23°00′13.1″S, 44°03′07.9″W (1 specimen) GoogleMaps   . Mangaratiba: 22°58′57.1″S, 44°03′04.7″W (2 specimens) GoogleMaps   . Praia de Muriqui: 22°55′43.4″S, 43°57′17.9″W (10 specimens) GoogleMaps   . Ibicuí: 22°57′45.3″S, 44°01′28.5″W (4 specimens) GoogleMaps   . Ilha da Marambaia: Praia de João Emanuel: 23°02′35.4″S, 43°57′42.0″W (7 specimens) GoogleMaps   . Praia da Armação: 23°02′39.9″S, 43°57′06.6″W (10 specimens) GoogleMaps   . Praia Suja: 23°03′57.2″S, 43°59′31.3″W (21 specimens) GoogleMaps   . Praia Grande: 23°03′57.5″S, 43°59′32.2″W (4 specimens) GoogleMaps   . Praia da Cutuca: 23°04′03.7″S, 43°59′42.2″W (10 specimens) GoogleMaps   . Rio de Janeiro State, Itaguaí Municipality: Ilha da Madeira: 22°55′06.3″S, 43°51′14.3″W (16 specimens) GoogleMaps   . Rio de Janeiro State, Angra dos Reis municipality   : Piraquara: 23°01′14.0″S, 44°26′24.5″W (8 specimens) GoogleMaps   . Dois Rios: 23°11′08.0″S, 44°11′24.4″W (2 specimens) GoogleMaps   .

Description (based on 10 individuals collected from Itacuruçá Island and Marambaia Island, Brazil)

Tube: Externally white/light pink and sometimes violet in smaller tubes, inside light pink ( Fig. 2 A View Figure 2 ). Subtriangular in cross-section, with a single prominent wavy median and longitudinal ridge, laterally with fine transverse growth markings, lacking alveoli and peristomes ( Fig. 2 A View Figure 2 ). Anterior end with a fine tooth extending over the opening ( Fig. 2 A View Figure 2 ). Attached to rocky shores, Perna perna ( Linnaeus, 1758)   mussels and artificial substrates, such as PVC plates.

Radiolar crown: Radioles arranged in a circle on each side, with 18 radioles per lobe. Inter-radiolar membrane extending to about ⅓ of radiolar length, smooth and bearing external rounded processes ( Fig. 2 B View Figure 2 ). Internally, radioles with two rows of pinnules of the same length. Terminal filament without pinnules. Stylodes absent. Eyespots absent. In live specimens, the bases of radioles (including the inter-radiolar membrane) exhibit a mix of black/pink/yellow/white pigments ( Figs. 2 B View Figure 2 , 3 A View Figure 3 , C-D). In fixed specimens, the radiolar crown has blue pigments ( Fig. 3 B View Figure 3 ).

Peduncle: Smooth, inserted left of the radiolar crown, near the medial line; dark pigments with irregular darker stripes on the dorsal side ( Fig. 3 View Figure 3 ); fixed specimens with blue pigments. Proximal area smooth and with narrow stem; distal area flattened and with a broad stem below the opercular plate ( Fig. 3 View Figure 3 ). Peduncle color extends into lateral wings. Pair of peduncular wings fringed with digitate processes ( Fig. 3 View Figure 3 ). Length: mean = 1.12 ( SD = 0.38; n = 10).

Operculum: Four distinct morphotypes, all with a circular calcareous opercular plate ( Fig. 3 View Figure 3 ). Type A: distal end of operculum conical and with concentric striations, without spines ( Fig.3 A View Figure 3 ). Type B: initial bifurcation of short non-ramified spines that share the same base and lack spinules, with two spines lying dorso-lateral and a third ventral to the top of the opercular plate ( Fig. 3 B View Figure 3 ). Type C: four spines, but a group of three shares the same base; two of which are dorso-lateral, larger and forked once, a third is ventral, smaller and also forked once; spines with spinules at their tips and not divided to the opercular plate ( Fig. 3 C View Figure 3 ). Type D: similar to type C,but the spines are developed totally and exhibit more ramifications at their tips than other types, spinules present. Dorso-lateral spines ramified three or two times, ventral spine ramified twice ( Fig. 3 D View Figure 3 ). Spines white. Diameter: mean = 0.7 ( SD = 0.16; n = 10);Width: mean = 0.71 ( SD = 0.18;n = 10).

Collar and thoracic membranes: Collar well-developed ( Figs. 2 B View Figure 2 , 3 C View Figure 3 ), covering ½ of the radiolar crown, divided into one ventral and two lateral lobes of the same size. Ventral lobe triangular. Tonguelet present, dark in colour (black) between ventral and latero-dorsal lobes. Laterodorsal lobes extend to thoracic membranes, producing a short ventral apron. Two types of collar chaetae: 1) limbate or 2) bayonet-like with many small teeth at the base of the ‘blade’ ( Fig. 4 A View Figure 4 ). Collar and thoracic membranes light brown in colour ( Fig. 3 C View Figure 3 ).

Thorax: Seven chaetigers, six of which are uncinigerous ( Fig. 2 B View Figure 2 ); collar fascicle without row of uncini. Thoracic chaetae limbate and of two different sizes ( Fig. 4 B View Figure 4 ). Uncini saw-shaped, with 9-10 teeth and including an anterior-most gouge-shaped peg tooth ( Fig. 4 D View Figure 4 ).

Abdomen: Number of abdominal chaetigers varies from 32 to 71 (mean = 49.9; SD = 15.93; n = 10). Chaetae trumpet-shaped ( Fig. 4 C View Figure 4 ). Uncini saw-shaped, with 10-12 teeth and including gouge-shaped peg tooth ( Fig. 4 E View Figure 4 ).

Measurements: Total length: mean = 5.4 ( SD = 2.0; n = 10); Thoracic length: mean = 1.24 ( SD = 0.36;

n = 10); Thoracic width: mean = 0.64 ( SD = 0.27; n = 10); Abdominal length: mean = 2.6 ( SD = 1.35; n = 10).

Remarks: Two species of Spirobranchus   have been reported for the Brazilian coast (Amaral et al., 2013), Spirobranchus giganteus ( Pallas, 1766)   and Spirobranchus minutus ( Rioja, 1941)   . Both of these species are readily discernible from our collected specimens, identified herein as S. tetraceros   .

The radioles of the radiolar crown in S. giganteus   are spirally arranged, and the wings of the penduncle form a smooth inverted triangle ( ten Hove, 1970). In contrast, the radioles of the radiolar crowns of our specimens are circularly arranged and the wings of the penduncle are fringed. The opercula of our specimens also differ from those of S.giganteus   . The opercular spines of S. giganteus   (two large ones, as well as other smaller ones) are ramified. The opercula of our specimens present four basic shapes ( Fig. 3 View Figure 3 ), varying from conical to a flat disc, and with three spines (one ventral and two lateral) sharing the same base ( Fig. 3 D View Figure 3 ).

Spirobranchus minutus   has three longitudinal ridges and alveoli at the base of the tube ( Rioja, 1941), unlike S. tetraceros   , that has serrated ridges along the tube forming a tip without alveoli. Moreover, S. minutus   has a triangular opercular penduncle with narrow and pointed wings ( Zibrowius, 1970), whereas that of S. tetraceros   is fringed with digitate wings. The operculum of S. minutus   is globose, almost transparent, extends over a calcified plate ( Zibrowius, 1970), and lacks spines.

The species of Spirobranchus   that occur in Curaçao (Caribbean Sea) were reviewed by ten Hove (1970), resulting in 22 taxa synonymized under the name S. tetraceros   . However, Bastida-Zavala & Salazar-Vallejo (2000) re-elevated Spirobranchus dendropoma ( Mörch, 1863)   to the species level based on their Mexican Caribbean material, distinguishing it from S. tetraceros   based on morphological and biogeographical differences (Perry et al., 2018). In their analyses of the material collected from the Mexican Caribbean, Bastida-Zavala & Salazar-Vallejo (2000) observed that their specimens were morphologically more similar to S. dendropoma   than to S. tetraceros   , and also considered biogeographic information in identifying the species. Herein, we consider morphological characters for our specimens identifications, including the position of processes extending from the radiolar membrane. These processes occur at the bases of the radioles in S. dendropoma   ( Benedict, 1887; ten Hove, 1970). In our examined specimens of S. tetraceros   , the interadiolar membrane processes occur between radioles and present a rounded shape.

Spirobranchus tetraceros   was originally described from New South Wales in Australia ( Schmarda, 1861), but it has also been recorded in the Red Sea (Perry et al., 2017), Mediterranean Sea, Hong Kong (Sun et al., 2012), Egypt, the Persian Gulf, and Curaçao ( ten Hove, 1970). This species was first recorded in Brazil at Arraial do Cabo (Skinner et al., 2012), and herein we expand its distribution to Sepetiba Bay and Ilha Grande, both of which are in the southeast of the country.

Habitat: The species were found attached to rocky shores, Perna perna   mussels and artificial substrates, such as PVC plates in subtidal areas.

Type-locality: New South Wales, Australia.

Distribution: West Pacific Ocean: Philippines; Port Jackson; Pandanon; Ubay; West Indian Ocean: Tanzania; Mozambique; Madagascar; Central Indian Ocean: Pearl Banks of Ceylon; Sri Lankan; Red Sea: Gulf of Aqaba; Red Sea; Djiboutian part of the Gulf of Aden; Persian Gulf; Mediterranean Sea; Lebanese part of the Mediterranean Sea; Greece; West Atlantic Ocean: Gulf of Mexico; Colombia ( Read, 2018b); Brazil, at Arraial do Cabo, misidentified as S. giganteus   , see Perry et al., 2017, Sepetiba Bay and Ilha Grande Bay (current work).

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Sabellida

Family

Serpulidae

Genus

Spirobranchus

Loc

Spirobranchus tetraceros ( Schmarda, 1861 )

Rodrigues, Andrielle Raposo, Skinner, Luis Felipe & Brasil, Ana Claudia dos Santos 2020
2020
Loc

Spirobranchus tetraceros: ten Hove, 1970 : p. 3-14

Kupriyanova et al. 2015: 337-339
Ben-Eliahu & ten Hove 2011: 88-94
ten Hove 1970: 3-14
1970
Loc

Pomatoceros tetraceros

Schmarda 1861: 30
1861