Invasion History

First Non-native North American Tidal Record: 1990
First Non-native West Coast Tidal Record: 1990
First Non-native East/Gulf Coast Tidal Record: 1997

General Invasion History:

Myrianida pachycera was described from Shark Bay, Australia. It is known form New South Wales (http://australianmuseum.net.au/image/Myrianida-pachycera/), the Seychelles (Böggemann et al. 2003), China (Huang 2001), and from the southern coast of Japan (Imajima et al. 1996b). Occurrences of this polychaete in Hawaii, California, and Florida probably represent introductions by shipping (Cohen et al. 2002; Nygren 2004; Imajima 1996b). This worm is frequently photographed, because of its bright colors and unusual appearance.

North American Invasion History:

Invasion History on the West Coast:

Myrianida pachycera was first seen in southern California sometime between 1986 and 2000 (Leslie Harris, personal communication, Cohen et al. 2000). In 2000-2001, it was found in San Diego Bay, Los-Angeles-Long Beach Harbor, Marina del Rey, King Harbor, and Port Huemene (Cohen et al. 2002; Nygren 2004; Cohen et al. 2005). Nygren (2004) collected it in epifauna on a ship. Transport in ship fouling is likely, as is ballast water transport of the reproductive stages.

Invasion History on the East Coast:

Myrianida pachycera was collected in the Indian River Lagoon, southern Florida, in 1997, in intertidal oyster beds (Nygren 2004). A specimen was photographed in the lagoon in 2013 by Dean Janiak (http://www.flickriver.com/photos/top_down/9429696118/), so this worm is presumed to be established in the Lagoon. Again, ship fouling or ballast water are likely vectors.

Invasion History in Hawaii:

Myrianida pachycera was first collected in Hawaii in Kaneohe Bay, Oahu in 1959. It has also been found in Pearl Harbor, where it was first collected in 1976-1977. It was associated with coral rubble, sponges, seaweeds, and fouling communities (Carlton and Eldredge 2009).

Invasion History Elsewhere in the World:

In 2016, three specimens of M. pachycera were found on fouling plates at Puerto Ayora, on Santa Cruz Island in the Galapagos Islands (Keppel et al. 2019).


Description

Myrianida pachycera is a marine syllid polychaete. Family characteristics include a relatively small and slender body; a prostomium with 2 pairs of eyes and sometimes eyespots; three antennae and paired palps; an eversible pharynx the anterior-most segment (peristomium) lacking chaetae but bearing 1–2 pairs of tentacles; uniramous parapodia (biramous in reproductive individuals); dorsal and ventral cirri on each chaetiger; and a pygidium (anal segment) with 2–3 anal cirri (Pettibone 1963; Blake and Ruff 2007). Reproduction in M. pachycera involves growing multiple segmented body sections (stolons), each of which can break off and swim away, then breaking apart to release eggs or sperm. The atokous (non-reproductive) section of the body consists of the prostomium, peristomium (anterior-most segment, lacking chaetae), and about 30–33 chaetigers, which are followed by a train of up to 10 stolons (Imajima 1966b; Nygren 2004).

Myrianida pachycera, in the atokous (non-reproductive) stage, is slender, and tapered posteriorly, with the ventral surface flattened and the dorsal surface arched. The prostomium has four eyes, arranged in a trapezoid, and bears three antennae, one located medially. The median antenna extends back to the 8th chaetiger. The lateral antennae are about half as long as the median antenna. The palps are small, directed ventrally, and fused at the base. The anterior-most segment (peristomium) bears two pairs of tentacular cirri. The antennae and the first two pairs of tentacular cirri, and the first pair of dorsal cirri, are longer than the cirri on the subsequent segments. The nuchal organs are grooves extending from the posterior end of the prostomium to chaetigers 4 to 7. The proboscis is S-shaped and ends in 9 soft papillae. It contains a ring (trepan) of 11–16 large teeth and 26–28 smaller teeth. The proventricle extends to chaetigers segment 8–10 or to 11–13. The cirri behind the first pair are shorter, broad, and blade-like, about as long as the body-width. The parapodia each bear two bundles of chaetae, much shorter than the cirri. The atokous section, or the last stolon, ends in a pygidium which terminates in a pair of anal cirri. The atokous section is 40–60 mm long, and often with an equal or greater length of stolons. This worm is brilliantly colored, with red eyes, bright-blue cirri, light blue parapodia, and a bright-orange central region. Except for a few anterior setigers, most have a bright blue dot in the center of each segment (Imajima 1966b; Nygren 2004).

The epitokous stages break off from the chain of stolons and according to the sex of the worm, develop into morphologically distinct male ('polybostrichus') and female ('sacconereis') forms. These develop new heads with three antennae and one pair of tentacular cirri. The parapodia of the chaetigers bear two bundles of long swimming chaetae. A preserved male specimen was 2.4 mm long, with 22 chaetigers (Nygren 2004), while females were 5–6 mm, with 31–35 setigers (Imajima 1996b; Nygren 2004). The female stages, early in development, are packed with ova, and later carry an external egg mass on their ventral surface (Imajima 1996b; Nygren 2014).
 

It is a favorite subject for photography because of its bright colors and long chains of stolons. One picture of this worm, by Dr. Greg Rouse, won 2nd place in a 2003 Nikon photomicrography contest (http://www.nikonsmallworld.com/galleries/entry/2003-photomicrography-competition/2)

 


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Annelida
Class:   Polychaeta
Subclass:   Palpata
Order:   Aciculata
Suborder:   Phyllodocida
Family:   Syllidae
SubFamily:   Autolytinae
Genus:   Myrianida
Species:   pachycera

Synonyms

Autolytus pachycerus (Augener, 1913)
Autolytus purpureimaculata (Okada, 1933)
Myrianida crassicirrata (Hartman-Schroeder, 1965)
Myrianida pachycera (Imajima, 1966)

Potentially Misidentified Species

Ecology

General:

Myrianida pachycera, like other members of the Syllidae, reproduces by epitoky. During epitoky the worm undergoes stolonization, in which segments of the body become modified for carrying gametes and swimming (modified setae, enlarged eyes). Sexes are separate, and the stolons break off from the stem portion of the worm's body, and swim in the water column as epitokes, with new heads, three antennae, and well-developed eyes. The stolons then regenerate. Male and female stolons are morphologically distinguishable (Imajima 1966b; Nygren 2004). The details of fertilization are not known, but the female carries the fertilized eggs in a long ventral egg mass while swimming in the water column (Imajima 1966b). Details of development are not known but in the related genus?Autolytus, the larvae are brooded and are lecithotrophic (Pettibone 1963). 
 
Myrianida pachycera occurs in warm-temperate to tropical climates, in the intertidal and shallow subtidal zone. It can be found in a variety of habitats including rocky reefs, oyster beds, coral reefs, muddy-silty bottoms, marinas, docks and ships’ hulls (Imajima 1966b; Nygren 2004; Carlton and Eldredge 2009). Syllids have been considered exclusively carnivorous, including members of the subfamily Autolytinae (including?Myrianida) feeding largely on hydroids (Fauchald and Jumars 1979). However, studies of fecal pellet of syllids indicate that many are omnivorous, including one species of Autolytus (Giangrande et al. 2000). 

Food:

Algae, invertebrates

Consumers:

Fishes, crabs, shrimps

Competitors:

Other free-moving polychaetes

Trophic Status:

Omnivore

Habitats

General HabitatCoarse Woody DebrisNone
General HabitatOyster ReefNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatVessel HullNone
General HabitatUnstructured BottomNone
General HabitatCoral reefNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatPlanktonicNone

Life History


Tolerances and Life History Parameters

Minimum Length (mm)2.4Male reproductive epitoke, preserved (Nygren 2004). Female epitokes are 5-6 mm
Maximum Length (mm)120A mature worm with a long train of stolons (Imajima 1966b; Nygren 2004).
Broad Temperature RangeNoneWarm temperate-Tropical
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Economic and ecological impacts are unknown for Myrianida pachycera


Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
P040 Newport Bay 2017 Non-native Established
P090 San Francisco Bay 2015 Non-native Established
NEP-V Northern California to Mid Channel Islands 2015 Non-native Established
P030 Mission Bay 2013 Non-native Established
P050 San Pedro Bay 2001 Non-native Established
P060 Santa Monica Bay 2000 Non-native Established
P020 San Diego Bay 2000 Non-native Established
P062 _CDA_P062 (Calleguas) 2000 Non-native Established
P050 San Pedro Bay 2000 Non-native Established
P053 _CDA_P053 (Santa Monica Bay) 2000 Non-native Established
P050 San Pedro Bay 2000 Non-native Established
NEP-VI Pt. Conception to Southern Baja California 1990 Non-native Established

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
697460 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-30 Pilot's Dock at Pier F Non-native 33.7472 -118.2156
697738 Introduced Species Study 2006 2006-08-24 Yellow Condos Non-native 33.7283 -118.0602
697800 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-29 Marina del Rey Non-native 33.9722 -118.4522
698298 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-25 Anacapa Isle Marina Non-native 34.1731 -119.2269
699095 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-26 Chula Vista Boat Ramp Non-native 32.6211 -117.1031
699687 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-29 King Harbor Non-native 33.8464 -118.3969
700683 Introduced Species Study 2006 2006-08-24 Private Beach Non-native 33.7175 -118.0659
701312 Introduced Species Study 2006 2006-10-10 Ferry Terminal Docks Non-native 33.3442 -118.3225
703038 Introduced Species Study 2011 2011-04-21 Long Beach Downtown Marina - ISS Non-native 33.7594 -118.1866
703517 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-26 Shelter Island Non-native 32.7100 -117.2342
703530 Introduced Species Study 2006 2006-09-14 Balboa Coves Non-native 33.6213 -117.9364
703621 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-31 Long Beach Yacht Club Non-native 33.7534 -118.1138
758997 Nygren 2004 2001 2001-01-04 Los Angeles Harbor Non-native 33.7507 -118.2674
767538 Ruiz et al., 2015 2013 2013-07-30 Hilton Resort Docks, Mission Bay, CA, California, USA Non-native 32.7791 -117.2128
769310 Ruiz et al., 2021b 2018 2018-08-06 Shoreline Public Marina, San Pedro Bay, California, USA Non-native 33.7586 -118.1856
769350 Ruiz et al., 2021b 2018 2018-08-06 Shoreline Public Marina, San Pedro Bay, California, USA Non-native 33.7586 -118.1856
769482 Ruiz et al., 2021b 2018 2018-08-12 Pacific Yacht Landing, San Pedro Bay, California, USA Non-native 33.7654 -118.2514
769514 Ruiz et al., 2021b 2018 2018-08-12 Pacific Yacht Landing, San Pedro Bay, California, USA Non-native 33.7654 -118.2514
769553 Ruiz et al., 2021b 2018 2018-08-12 Pacific Yacht Landing, San Pedro Bay, California, USA Non-native 33.7654 -118.2514
769565 Ruiz et al., 2021b 2018 2018-08-12 Pacific Yacht Landing, San Pedro Bay, California, USA Non-native 33.7654 -118.2514
769632 Ruiz et al., 2021b 2018 2018-08-07 Peter's Landing Marina, San Pedro Bay, California, USA Non-native 33.7252 -118.0766
770208 Ruiz et al., 2021b 2018 2018-08-14 Island Yacht Anchorage, San Pedro Bay, California, USA Non-native 33.7668 -118.2408
770627 Ruiz et al., 2021b 2017 2017-08-04 Marina Park, Newport Bay, California, USA Non-native 33.6085 -117.9222
774586 Ruiz et al., 2022 2015 2015-07-27 Esprit Marina, Marina del Rey, California, USA Non-native 33.9757 -118.4497
774587 Ruiz et al., 2022 2015 2015-07-31 Del Rey Marina-Basin E, Marina del Rey, California, USA Non-native 33.9825 -118.4513
774589 Ruiz et al., 2022 2015 2015-07-30 Dolphin Marina, Marina del Rey, California, USA Non-native 33.9782 -118.4529
774590 Ruiz et al., 2022 2015 2015-08-01 Holiday Marina, Marina del Rey, California, USA Non-native 33.9797 -118.4549
774591 Ruiz et al., 2022 2015 2015-07-28 Santa Monica Yacht Club, Marina del Rey, California, USA Non-native 33.9781 -118.4455
774680 Ruiz et al., 2022 2015 2015-09-21 Redwood City Marina, San Francisco Bay, California, USA Non-native 37.5022 -122.2129
774683 Ruiz et al., 2022 2015 2015-09-21 Redwood City Marina, San Francisco Bay, California, USA Non-native 37.5022 -122.2129
774685 Ruiz et al., 2022 2015 2015-09-21 Redwood City Marina, San Francisco Bay, California, USA Non-native 37.5022 -122.2129
774698 Ruiz et al., 2022 2015 2015-09-17 Ballena Isle Marina, San Francisco Bay, California, USA Non-native 37.7679 -122.2863
774700 Ruiz et al., 2022 2015 2015-09-17 Ballena Isle Marina, San Francisco Bay, California, USA Non-native 37.7679 -122.2863
774710 Ruiz et al., 2022 2015 2015-09-23 Oyster Point Marina, San Francisco Bay, California, USA Non-native 37.6630 -122.3798
774723 Ruiz et al., 2022 2015 2015-09-22 Coyote Point Marina, San Francisco Bay, California, USA Non-native 37.5887 -122.3164
774788 Ruiz et al., 2022 2016 2016-09-22 Coyote Point Marina, San Francisco Bay, California, USA Non-native 37.5898 -122.3165
774790 Ruiz et al., 2022 2016 2016-09-26 Redwood City Marina, San Francisco Bay, California, USA Non-native 37.5027 -122.2138
774792 Ruiz et al., 2022 2016 2016-09-26 Redwood City Marina, San Francisco Bay, California, USA Non-native 37.5027 -122.2138
774797 Ruiz et al., 2022 2016 2016-09-26 Redwood City Marina, San Francisco Bay, California, USA Non-native 37.5027 -122.2138

References

Atlas of Living Australia 2013-2016 Atlas of Living Australia. <missing URL>



Australian Museum 2014 Atlas of Living Australia- Data Sets. <missing URL>



Blake, James A.; Ruff, R. Eugene (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of California, Berkeley CA. Pp. 309-410

Boggemann, Markus; Hessling, Rene; Westheide, Wilfried (2003) Horizontal distribution of the syllid fauna (Annelida: Polychaeta) in the fringing reef lagoon of Anse Forbans (Mahe, Seychellles) and redescription of the abundant Streptosyllis aequiseta, Hydrobiologia 496: 17-26

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

Carlton, James T.; Eldredge, Lucius (2009) Marine bioinvasions of Hawaii: The introduced and cryptogenic marine and estuarine animals and plants of the Hawaiian archipelago., Bishop Museum Bulletin in Cultural and Environmental Studies 4: 1-202

Cohen, A. N. and 11 authors (2005) Rapid assessment survey for exotic organisms in southern California bays and harbors, and abundance in port and non-port areas., Biological Invasions 7: 995-1002

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Fauchald, Kristian (1984) Polychaete distribution patterns, or: can Animals with Palaeozoic cousins show larger-scale geographical patterns?, Proceedings of the First International Polychaete Conference <missing volume>: <missing location>

Giangrande, Adriana; Licciano, Margheritia; Pagliaria, Patrizia (2000) The diversity of diets in Syllidae (Annelida: Polychaeta), Cahiers de Biologie Marine 41: 55-65

Huang, Zongguo (Ed.), Junda Lin (Translator) (2001) Marine Species and Their Distributions in China's Seas, Krieger, Malabar, FL. Pp. <missing location>

Imajima, Minoru (1966b) The Syllidae (polychaetous annelids) from Japan II. Autolytinae, Publications of the Seto Marine Biological Laboratory 14(1): 27-83

Keppel, Erica; , Keith, Inti; Ruiz, Gregory M.; Carlton, James T. (2019) New records of native and non-indigenous polychaetes (Annelida: Polychaeta) in the Galapagos Islands, Aquatic Invasions 14(1): 59-84

Nygren, Arne (2004) Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680: 1-314

Pettibone, Marian H. (1963) Marine polychaete worms of the New England region. 1. Aphroditidae through Trochochaetidae., Bulletin of the United States National Museum 227(Part 1.): 1-356

Quintanilla, Elena; Thomas Wilke; Ramırez-Portilla, Catalina; Sarmiento, Adriana; Sanchez, Juan A.2017 (2017) Taking a detour: invasion of an octocoral into the Tropical Eastern Pacific, Biological Invasions <missing volume>(17): 2583–2597
DOI 10.1007/s10530-017-1469-2



Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Ruiz, Gregory; Geller, Jonathan (2021) Spatial and temporal analysis of marine invasions: supplemental studies to evaluate detection through quantitative and molecular methodologies, Marine Invasive Species Program, California Department of Fish and Wildlife, Sacramento CA. Pp. 153 ppl.

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database. http://collections.nmnh.si.edu/search/iz/