Spionid polychaetes (Annelida: Spionidae) boring into shells of molluscs of commercial interest in northern Patagonia, Argentina

Figures & data

Figure 1. Map showing sampling sites in San José and Nuevo Gulfs, northern Argentine Patagonia.

Table I. Infestation of bivalve molluscs by spionid polychaetes in northern Patagonia. Bivalves are arranged according to the prevalence of the infestation. Shell size (height) is given with mean and range. Prevalence and intensity were calculated per valve

Boring spionid	Host bivalve (family)	N molluscs	Shell height (mm) mean (range )	Prevalence (%)	Intensity	Burrow shape	Collecting site
Polydora rickettsi	Aequipecten tehuelchus (Pectinidae)	86	73.3 (42–88)	54	1–9	Mud blisters and U-shaped burrows	San Román, Bengoa Beach, Punta Conos and Fracasso Beach
	Aulacomya atra (Mytilidae)	106	91.4 (66–122)	37	1–6	Irregular burrows	Fracasso Beach and Punta Gales
	Ostrea puelchana (Ostreidae)	33	90 (55–108)	36	1–2	Irregular burrows	Fracasso Beach
	Pododesmus rudis (Anomiidae)	26	58.5 (44–75)	53	1–2	Irregular burrows and T-shaped burrows	Bengoa Beach
	Protothaca antiqua (Veneridae)	32	46 (41–65)	20	1–3	Irregular burrows	San Román
Dipolydora cf. giardi	Aulacomya atra (Mytilidae)	106	91.4 (66–122)	37	1–6	Irregular burrows	Punta Gales and Puerto Madryn

Figure 2. Adult morphology of Polydora rickettsi. A, anterior end, dorsal view; B, modified chaetae of segment 5; C, pygidium. Scale bars: A, C, 50 μm. B, 30 μm.

Figure 3. Polydora rickettsi in life. A, individual inside its burrow, in shell of Pododesmus rudis; B, egg capsules inside a burrow in a shell of A. tehuelchus; C, palps projecting from the shell of Protothaca antiqua; D, U-shaped burrow in a shell of A. tehuelchus; E, T-shaped burrow in a shell of P. rudis.

Figure 4. Adult morphology of Dipolydora cf. giardi. A, anterior end, dorsal view; B, pygidium; C, modified chaetae of segment 5. Scale bars: A, B, 50 μm. C, 30 μm.