Diplocirrus SD1

Invasion History

First Non-native North American Tidal Record: 1995
First Non-native West Coast Tidal Record: 1995
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Diplocirrus SD1 was described as an unidentified species by Rowe (1998) from San Diego Bay. Rowe mentioned an earlier (1995), unidentified specimen from Agua Hedionda Lagoon, Carlsbad, California (Larry Lovell, unpublished). In a coastal survey, it was found in Anaheim Bay, Mission Bay, and San Diego Bay (Ranasinghe et al. 2005). This polychaete resembled D. capensis, described from South Africa, and reported from Madagascar (Day 1973; Darbyshire and Mackie 2009). Records of D. capensis from North Carolina (Day 1973; Salazar-Vallejo and Buzhinskaja 2011) are questionable.

North American Invasion History:

Invasion History on the West Coast:

Diplocirrus SD1 was first collected in 1995 in Agua Hedionda Lagoon, Carlsbad, California (Larry Lovell, unpublished). This specimen was identical to specimens collected in 1998 in San Diego Bay (Rowe 1998). In a 1998 survey, this polychaete was collected in Anaheim Bay, Mission Bay, and San Diego Bay (Ranasinghe et al. 2005). The mode of development in Diplocirrus SD1 is unknown. Some polychaetes of the family Flabelligeridae have planktonic larvae, while others have direct development (Carson and Hentschel 2006). Ballast water is a possible vector for introduction. The mode of transport to smaller harbors, such as Anaheim Bay, Agua Hedionda Lagoon, and Mission Bay is unclear, since flabelligerids have not been reported from fouling communities. However, Diplocirrus SD1 does occur abundantly in the sediment of yacht harbors (Neira et al. 2014).

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Description

Diplocirrus SD1 belongs to the family Flabelligeridae. Flabelligeids are sedentary, infaunal deposit feeders. Features include a thick body, which is tapered posteriorly, with the oral apparatus, prostomium, peristomium, palps, and 8 branchiae all normally concealed by a sheath (extruded when feeding). Further characteristics include a thick cuticle, ornamented with papillae, and reduced parapodia. Many worms of this family, including most of the genus Diplocirrus are marked by a dense cluster of elongated chaetae, anteriorly directed, and protruding from the first few chaetigers, surrounding the mouth, and called the 'feeding cage'. This feature is greatly reduced in the unidentified D. SD1 Rowe 1998, and absent in the similar D. capensis (Day 1973; Salazar-Vallejo and Buzhinskaja 2011).

In Diplocirrus SD1, the anterior 9 chaetigers are somewhat inflated, with weakly defined furrows between the segments. Beginning with chaetiger 10, the furrows are deeper, while the more posterior chaetigers resemble a string of beads. The body is covered with flask-shaped papillae, randomly arranged, but very dense posteriorly, and with more open areas anteriorly. The four outer papillae are large, squared, and here to each other, while the inner ones are cirriform. All the parapodia are greatly reduced, to separated bundles of notochaetae and neurochaetae. Up to 4 notochaetae in each bundle of the first chaetiger are directed forward to form a very minimal feeding cage. The notochaetae are long and thin, with widely spaced crossbars. The neurochaetae are shorter, but also thin, with crossbars. The anal opening is subterminal, dorsal, and without accessory structures. The specimen described by Rowe (1998) was 19 mm long and 45 chaetigers. A photographed specimen is brown, it is not clear whether it was live or preserved.

Day (1973) described the somewhat similar D. capensis, from South Africa, as having 8 similar cirriform branchiae, but when re-examined, there were two types: stout and wedge-shaped, and cirriform (Darbyshire and Mackie 2009). This change increases the resemblance between D. capensis and D. SD1.

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Taxonomy

Ecology

General:

Diplocirrus SD1 is an infaunal polychaete of the the family Flabelligeridae. We have little information on reproduction in this species. Salazar-Vallejo et al. (2011) reported finding mature females of several species, contaning eggs. Carson and Henschel (2006; supplementary table), citing several sources, indicate that worms of this family vary in reproductive mode, with some species having direct development, while others have planktonic larvae.

Diplocirrus is a marine free-living, head-up surface deposit feeder. Many worms of the family Flabelligeridae, including most of the genus Diplocirrus have a dense cluster of elongated chaetae, anteriorly directed, and protruding from the first few chaetigers, surrounding the mouth, and called the 'feeding cage' (Darbyshire and Mackie 2009; Salazar-Vallejo et al. 2011). However, this feature is reduced in Diplocirrus SD1 (Rowe 1998). 'Most flabelligerids are discretely motile and feed while sitting in cracks and crevices' (Hartmann-Schroder 1971, cited by Fauchauld and Jumars 1979). These worms use their palps to gather diatoms, fragments of large algae, and detritus from the sediment surface (Fauchauld and Jumars 1979).

Food:

Detritus, microalgae

Trophic Status:

Deposit Feeder

DepFed

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Habitats

General Habitat	Unstructured Bottom	None
General Habitat	Marinas & Docks	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Endobenthic	None

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Tolerances and Life History Parameters

Maximum Length (mm)	19	Length of the specimen described by Rowe (1998). The type specimen of D. capensis was 12 mm (Day 1973).
Broad Temperature Range	None	Warm-Temperate
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

The biology and ecology of Diplocirrus SD1 has not been studied, and its impacts are unknown.

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References

California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

Carson, Henry S.; Hentschel, Brian T. (2006) Estimating the dispersal potential of polychaete species in the Southern California Bight: implications for designing marine reserves, Marine Ecology Progress Series 316: 105-113

Darbyshire, Teresa; Mackie, Andrew S. Y. (2009) Two new species of Diplocirrus (Polychaeta: Flabelligeridae) from the southern Irish Sea and South Africa, Zoosymposia 2: 91-103

Day, J. H. (1955) The Polychaeta of South Africa. Part e: Sedentary species of Cape shores and estuaries, Journal of the Linnean Society of London- Zoology 42: 407-452

Day, John H. (1973) New polychaeta from Beaufort, with a key to all species recorded in North Carolina, NOAA Technical Report NMFS Circular 375: 1-140

Fauchald, Kristian; Jumars, Peter A. (1979) The diet of worms : A study of polychaete feeding guilds, Oceanography and Marine Biology, an Annual Review 17: 193-284

Neira, Carlos; Levin, Lisa A.; Mendoza, Guillermo; Zirino, Alberto (2014) Alteration of benthic communities associated with copper contamination linked to boat moorings, Marine Ecology 35: 46-66

Ranasinghe, J. Ananda and 6 authors. (2005) The prevalence of non-indigenous species in southern California embayments and their effects on benthic macroinvertebrate communities, Biological Invasions 7: 679-686

Rowe, R. 1998 City of San Diego Provisional Voucher Sheet: Provisional name <i>Diplocirrus</i> SD1. <missing URL>



Salazar-Vallejo, Sergio I.; Buzhinskaja, Galina (2011) Revision of Diplocirrus Haase, 1915, including Bradiella Rullier, 1965, and Diversibranchius Buzhinskaja, 1993 (Polychaeta, Flabelligeridae), ZooKeys 106: 1-45

Shimbukuro, Mauricio (2011) <missing title>, University of Sao Paulo, <missing place>. Pp. 1-22

Tosuji, Hiroaki; Furota, Toshio (2016) Molecular evidence for the expansion of the Asian cryptic invader Hediste diadroma (Nereididae: Annelida) into the Northeast Pacific habitats of the native H. limnicola, Zoological Science 33(2): 162-169

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