Invasion History

First Non-native North American Tidal Record: 1967
First Non-native West Coast Tidal Record: 1967
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

The bryozoan Victorella pavida was first identified from the London docks by Saville-Kent (1870). It has subsequently been recorded from many European ports (Carrada and Sacchi 1964; D'Hondt 1983; Occhipinti Ambrogi and d'Hondt 1981; Partaly 1979), the Black and Caspian Seas (Mordukhai-Boltovskoi 1964), Israel (Massard et al. 1992), India, Thailand (Wood et al. 2006), Japan, California (Menon and Nair 1967; Winston 1977; Carlton 1979), and the Atlantic and Gulf Coasts of North America (Osburn 1944; Everitt 1975).

Carlton (1979), while acknowledging taxonomic difficulties, has suggested that V. pavida is a species of Indo-Pacific origin which has been transported worldwide by ships, first to Britain and elsewhere in Europe, then to the east coast of North and South America, and later to the West Coast (Lake Merritt, Oakland, CA; 1967) by way of Japan. However, Mordukhai-Boltovskoi (1964) regarded this bryozoan as native to the Ponto-Caspian region and introduced worldwide, as was the hydroid Cordylophora caspia. It appears that careful comparisons of morphology of live organisms and genetic studies will be needed to determine the origins of this species or species complex. Victorella pavida is probably introduced in England and northern Europe. Marine biology was such a widespread interest there in the late 1800's, it is likely that native populations would have been recognized much earlier if they existed. We treat this bryozoan as introduced in Northern Europe and along the Pacific coast of North America where it has a scattered distribution, and is largely confined to ports. We consider it cryptogenic in the Mediterranean, Ponto-Caspian region, Western Atlantic, and Indo-Pacific, all possible regions of origin and/or the occurrence of potentially misidentified species.

North American Invasion History:

Invasion History on the West Coast:

On the Pacific Coast of North America, Victorella pavida is a definite introduction. It was found in Lake Merritt, Oakland, California, in 1967 (Carlton 1979). It had not been collected in other San Francisco Bay locations until it was found in the Turning Basin of the Petaluma River in 2004 (Cohen et al. 2005). Victorella pavida has also been found in the Tijuana River, San Diego, and in Elkhorn Slough (de Rivera et al. 2005).

Invasion History on the East Coast:

We consider Victorella pavida to be cryptogenic on the East and Gulf coasts, because of uncertainty in its identification. Some of the V. pavida identified from the Atlantic coast of the US, including specimens illustrated by Osburn (1944) from Chesapeake Bay, may be Tanganella appendiculata, presumably a native North American species, first described in 1982 from Martha's Vineyard, Massachusetts. Victorella pavida and Tanganella spp. can only be distinguished in living material, and consequently many 'Victorella' identifications are uncertain (Jebram and Everitt 1982). We will refer to records which could be V. pavida, T. appendiculata, or other related species as 'V. pavida (s.l.)' (for 'sensu lato', meaning in the broad sense). Winston (personal communication) examined live 'V. pavida (s.l.)' specimens from fouling plates from Baltimore Harbor, but has not yet determined the identity of the organisms.

On the East Coast, Victorella pavida was first reported from the lower Chesapeake Bay, off Cape Charles City, Virginia, in a biological survey of the Bay in 1915-1922 (Cowles 1930; Osburn 1932). However, this bryozoan may have been present earlier. The first collections of Victorella pavida were in the mid-to-lower Bay, at locations between James Island, MD and Cape Charles City, VA (Cowles 1930; Osburn 1932). Osburn (1944) later reported that it ranged over 3-27 ppt, with an optimum around 10-14 ppt. He also noted that 'Where it is abundant, it is a nuisance in fouling the bottoms of boats... Oysters and barnacles may be covered to the edges of their shells' (Osburn 1944). Bibbins (1893), studying Cordylophora in Furnace Creek, Baltimore Harbor, noted 'dense and beautiful growths of bryozoans', most likely Victorella pavida (s. l.). since this is the only bryozoan occurring there now (Ruiz et al., unpublished). Victorella pavida (s. l.) has also been reported from North Carolina (in 1973, Dean and Bellis 1975), South Carolina (Calder and Maturo 1978); Florida (in 1975, Winston 1982), Mississippi (in 1975, Poirrier and Mulino 1977), Louisiana (in 1971, Everett 1975, Poirrier and Mulino 1977), and Texas (Corpus Christi, Galveston Bay, in 2003, Ruiz et al., unpublished data). Chesapeake Bay appears to be its northern limit on the Atlantic Coast.

Invasion History Elsewhere in the World:

Victorella pavida is apparently introduced in northern Europe. It was described from the London docks on the Thames River (type locality, Saville-Kent 1870; Carrada and Sacchi 1969). It was subsequently reported from many other European ports, including Ostend, Belgium, the Zuiderzee, Netherlands, in Bergues, Dunkerque, and Caene in Normandy, France, and the Aber estuary, in Roscoff (Brittany), France (Carrada and Sacchi 1969). Victorella pavida is no longer found at some locations, including the Thames estuary, and the Zuiderzee, Netherlands (Carrada and Sacchi 1969). Currently, in the British Isles, Victorella pavida is only found in Swanpool: a brackish water lagoon near Falmouth in Cornwall (MarLin 2009; Carter et al. 2010). In the Baltic, V. pavida was first found in the Greifswald Bodden, a lagoon of the Baltic in Germany, in 1880 (Nehring 2001). It has been found in several locations in Germany, Sweden, Poland, and Finland (Carrada and Sacchi 1969).

Victorella pavida (s.l) is widely reported in warmer parts of the world, where we regard it as cryptogenic. It is recorded from estuaries in Mondevideo and Rio de la Plata, Uruguay and Sao Paulo and Rio de Janeiro, Brazil (Marcus 1955). It is also known from coastal lagoons on the Atlantic coast of Morocco, and throughout the Mediterranean (Carrada and Sacchi 1969), the Black and Caspian Seas (Mordukhai-Boltovskoi 1964; Carrada and Sacchi 1969), the east and west coasts of India (Menon and Nair 1967; Rao and Ganapati 1975), fresh and brackish waters of Thailand (Wood et al. 2006), and Matsushima Bay, Japan (Toriumi 1944, cited by Winston 1977). Some of these records may consist of closely related species and genera.


Description

Victorella pavida is an erect, un-calcified bryozoan, found in fresh and brackish waters. Its colonies form diffuse branching chains, or dense clumps of tubular zooids, which are closely or loosely attached to a substratum. Colonies can form a dense mat 3-6 mm high as creeping colonies, but can grow into branching forms 15 mm high, and can spread over a radius of 100-150 mm. The zooids are variable in shape and size. On bare surfaces, it forms creeping colonies of zooids 300-430 µm long and about 150-160 µm thick. Buds form from the basal portion of the zooids. About 180-220 mm of the length, in the distal portion, is the peristomial tube- when the polypide retracts the tube contains only the setae, which form a collar around the mouth and tentacles. As the colony becomes more crowded, the zooids become erect and longer, reaching 1000-1200 µm, joined by short proximal tubes. In erect zooids, budding can occur from the midpoint of the zooid. The new branching zooid can have a long proximal tube, up to 1500 µm, leading to a wider portion, about 450-500 µm, where the polypide is housed. The polypide has a collar of setae and eight tentacles around the mouth. Two of the tentacles are bent sharply away from the others. The pharynx and esophagus leads to the expanded cardia region of the stomach- this species lacks a gizzard. Sexually reproductive zooids develop an intratentacular organ for releasing eggs. The embryos develop in an invagination of the dorsal wall of the vestibule (description from: Osburn 1944; Carrada and Sacchi 1964; Ryland 1965; Winston 1982; Hayward 1985; Wood et al. 2006; Winston and Hayward 2012). Under stressful conditions, colonies form modified zooids, called hibernacula, which are brown, dome-shaped structures, 160-201 µm in diameter, which serve as propagules for surviving cold, hypoxia, or other stresses (Carter et al. 2010).

Taxonomy - There is considerable uncertainty in the taxonomy and identification of Victorellidae and related bryozoans. Many important morphological features cannot be seen in preserved material and the colonies can change form as they grow (Jebram and Everitt 1982). Victorella pavida has been perceived either as a naturally cosmopolitan species (Hyman 1959), or as one widely introduced worldwide (Carlton 1979), but some populations originally identified as V. pavida may be other species of Victorella or other genera (TanganellaNolellaBulbella, etc.) (Jebram and Everitt 1982).

In the genus Victorella, the cardial sphincter is located at the midpoint of the cardial region (rather than at the beginning of the digestive caecum, as in Tanganella) (Jebram and Everitt 1982). However, gut morphology is difficult to observe, and its taxonomic value is untested (Wood et al. 2006). In the genus Bulbella, only erect zooids occur, and the larvae are brooded externally. Based on other criteria, at least six species of Victorella have been recognized, but their validity is uncertain (Wood et al. 2006). Osburn's (1932) identification of Victorella pavida from Chesapeake Bay was somewhat provisional; comments from British Museum taxonomists Harmer and Kirkpatrick were: 'Your example differs a good deal from the typical material; but on the other hand resembles closely the figures of Kraepelin. We are both inclined to think that you would not be far wrong if you named your specimen 'Victorella pavida.' So the determination stands and must remain until better preserved material can be properly studied'. Osburn (1944), Poirrer and Mulino (1977b) and other authors had noticed a correlation between decreasing salinity and decreased branching of 'Victorella pavida' colonies. Jebram and Everitt (1982) suggest that this may represent differences among cryptic species. Wood et al. (2006) observed a high degree of variability in cultured and wild colonies in freshwater in Thailand, depending on crowding, and possibly seasonal and environmental influences.

The possible distinctions among multiple species potentially confused with Victorella pavida, are likely to be missed in earlier work and in most routine fouling surveys. Given the uncertainty over species identification, records from the Chesapeake and other localities, as well as life history and community data, should be regarded as 'V. pavida 'sensu lato' (in the broad sense, ignoring possible cryptic speciation- 's. l.' for short) unless we have noted them as more closely identified. Dr. Judy Winston has identified 'Victorella pavida s. l.', resembling Osborn's material from Chesapeake Bay, including material from the Smithsonian Environmental Research Center 'Invasions Group' settling plates (Winston personal communication).


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Bryozoa
Class:   Gymnolaemata
Order:   Ctenostomata
Suborder:   Carnosa
Superfamily:   Paludicelloidea
Family:   Victorellidae
Genus:   Victorella
Species:   pavida

Synonyms

Victorella bengalensis (Annandale, 1908)

Potentially Misidentified Species

Bowerbankia gracilis
Bowebankia spp. bud from the stolons, and have a gizzard. All 8 tentacles are uniformly straight or curved.

Bowerbankia imbricata
None

Bowerbankia teritia
None

Bulbella abscondita
This species was described from Martha's Vineyard, Massachusetts (Jebram and Everitt 1982).

Tanganella appendiculata
This species was described from Martha's Vineyard, Massachusetts (Jebram and Everitt 1982)

Tanganella muelleri
This species has been reported from European waters (Baltic-Mediterranean). There is one report from Cape Cod, Massachusetts.

Victorella pseudoarachnida
This species was described from Salton Sea, California.

Ecology

General:

Life History- Victorella pavida is a soft-bodied bryozoan, which forms creeping or bush-like colonies composed of many individual zooids. The zooids feed by extending the ciliated tentacles of the lophophore as a funnel, creating a current, and driving food particles into their mouths. The food is guided along the tentacles and through the pharynx by the cilia. Larger food particles can be moved or captured by flicking or contracting the tentacles. The zooids are hermaphroditic, and produce large yolky eggs, which hatch into lecithotrophic larvae that are planktonic for short periods (less than 1-2 days). Larvae settle on a substrate and metamorphose into the first zooid of a colony, an ancestrula (Hyman 1959; Barnes 1983). Under stressful conditions, including falling temperatures, and hypoxia, zooids form structures called hibernacula, which survive when the colony dies back. Hibernacula remain attached to the substratum, and are not viable for more than a year (unlike the statoblasts of most freshwater bryozoans) (Carter et al. 2010).

Ecology- Victorella pavida has been found attached to vegetation, woody debris, jetties, shells, pilings, and boats (Osburn 1944; Maturo 1957). This bryozoan has been reported from freshwater in India, Thailand, and Louisiana, but is best known from brackish waters (Osburn 1944; Carrada and Sacchi 1964; Everitt 1975; Poirrier, and Mulino 1977; Massard et al. 1992; Wood et al. 2006). Populations in different regions seem to vary greatly in salinity tolerance, which could reflect either intraspecific genetic differences or cryptic speciation. Colonies in England grew poorly at salinities below 9 PSU (Carter et al. 2010), while in Thailand this bryozoan is widespread in fresh water (Wood et al. 2006). In India, colonies that settled during the monsoon period at 0.3-5.2 PSU, had 100% 24-hour survival, while those that settled in the post-monsoon period at 14.6-22.4 PSU did not survive in freshwater (Menon and Nair 1967).

Food:

Phytoplankton, detritus

Trophic Status:

Suspension Feeder

SusFed

Habitats

General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatOyster ReefNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatCanalsNone
General HabitatVessel HullNone
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeLimnetic0-0.5 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone


Tolerances and Life History Parameters

Minimum Temperature (ºC)0Field data- Nauman and Cory 1968
Maximum Temperature (ºC)37.8Field data (Thermal effluent)- Nauman and Cory 1969)
Minimum Salinity (‰)0Field Data- Carrada and Sacchi 1964; Cowles 1930; Osburn 1944; Menon and Nair 1967; Everitt 1975; Poirrier and Mulino 1977b; Winston 1977; Wood et al. 2006
Maximum Salinity (‰)36Experimental data (Carter et al. 2010); 22-30 PSU, Field Data- Carrada and Sacchi 1964; Cowles 1930; Osburn 1944; Menon and Nair 1967; Everitt 1975; Poirrier and Mulino 1977b; Winston 1977; Wood et al. 2006).
Minimum Duration0.1Larval period- Carrada and Sacchi 1964; Hyman 1959
Maximum Duration1Larval period- Carrada and Sacchi 1964; Hyman 1959
Maximum Height (mm)15Osburn 1944
Broad Temperature RangeNoneCold temperate-Tropical
Broad Salinity RangeNoneNontidal limnetic-Polyhaline

General Impacts

Economic Impacts

Industry - Victorella pavida (s. l.) is an important fouling organism on power plants and other industrial equipment in estuarine waters of the Patuxent River, Chesapeake Bay (Nauman and Cory 1969) and the Sea of Azov (Partaly 1979).

Boating - Victorella pavida (s. l.) is 'a nuisance fouling species on the bottom of boats' in Chesapeake Bay (Osburn 1944; Lippson and Lippson 1984).

Ecological Impacts

Competition - Victorella pavida (s. l.) is presumed to compete for space in mesohaline fouling communities with the introduced hydroids Cordylophora caspia and Garveia franciscana, which are also frequently dominant in fouling communities (Cory 1967; Nauman and Cory 1969; Abbe 1987; Ruiz et al. unpublished data).

Habitat Change - Victorella pavida (s. l.) colonies provide habitat for a wide variety of small motile animals (amphipods, polychaetes, etc.) in Chesapeake Bay (Ruiz et al. unpublished observations).

Regional Impacts

NA-ET3Cape Cod to Cape HatterasEcological ImpactCompetition
Victorella pavida (s. l.) is one of the dominant fouling organisms in summer in Chesapeake Bay (Osburn 1944; Cory 1967; Lippson and Lippson 1984; Abbe 1987) and is presumed to compete with other fouling taxa for space in mesohaline fouling communities, including native barnacles and the introduced hydroids Cordylophora caspia and introduced Garveia franciscana, which are also frequently dominant in fouling communities (Cory 1967; Nauman and Cory 1969; Abbe 1987; Ruiz et al. unpublished data).
NA-ET3Cape Cod to Cape HatterasEcological ImpactHabitat Change
Victorella pavida (s. l.) colonies provide habitat for a wide variety of small motile animals (amphipods, polychaetes, etc.) in Chesapeake Bay (Ruiz et al. unpublished observations).
NA-ET3Cape Cod to Cape HatterasEconomic ImpactShipping/Boating
Boating - Victorella pavida (s. l.) is 'a nuisance fouling the bottom of boats' in Chesapeake Bay (Osburn 1944; Lippson and Lippson 1984).
NA-ET3Cape Cod to Cape HatterasEconomic ImpactIndustry
Victorella pavida (s. l.) is an important fouling organism in power plants and other industrial users of estuarine waters in the Patuxent River, Chesapeake Bay (Nauman and Cory 1969).
MED-XNoneEconomic ImpactIndustry
Victorella pavida (s. l.) is an important fouling organism in power plants and other industrial users of estuarine waters in the Sea of Azov (Partaly 1979).
MED-XNoneEcological ImpactCompetition
'Thus, larvae of bryozoan foulings settle in the Sea of Azov in the summer and appear in biocoenosis with a high number of mature barnacles and growing hydroids. The bryozoans settle on the remaining free area of barnacles and growing hydroids. The bryozoans settle on the remaining free area of barnacles and hydroids and depress them.' (Partaly 1979).

M130Chesapeake BayEcological ImpactCompetition
Victorella pavida (s. l.) is one of the dominant fouling organisms in summer in Chesapeake Bay (Osburn 1944; Cory 1967; Lippson and Lippson 1984;  Abbe 1987) and is s presumed to compete with other fouling taxa for space in mesohaline fouling communities, including native barnacles and the introduced hydroids Cordylophora caspia and introduced Garveia franciscana, which are also frequently dominant in fouling communities (Cory 1967; Nauman and Cory 1969; Abbe 1987; Ruiz et al. unpublished data).
M130Chesapeake BayEcological ImpactHabitat Change
Victorella pavida (s. l.) colonies provide habitat for a wide variety of small motile animals (amphipods, polychaetes, etc.) in Chesapeake Bay (Ruiz et al. unpublished observations).
M130Chesapeake BayEconomic ImpactIndustry
Victorella pavida (s. l.) is an important fouling organism in power plants and other industrial users of estuarine waters in the Patuxent River, Chesapeake Bay (Nauman and Cory 1969).
M130Chesapeake BayEconomic ImpactShipping/Boating
Boating - Victorella pavida (s. l.) is 'a nuisance fouling the bottom of boats' in Chesapeake Bay (Osburn 1944; Lippson and Lippson 1984).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NEA-II None 1870 Def Estab
NEA-III None 1983 Def Estab
NEA-IV None 1962 Def Estab
MED-IX None 1936 Crypto Estab
MED-X None 1967 Crypto Estab
B-X None 1927 Def Estab
B-III None 1969 Def Estab
B-VII None 1964 Def Estab
B-IV None 1880 Def Estab
MED-V None 1951 Crypto Estab
MED-VI None 1936 Crypto Estab
MED-VII None 1961 Crypto Estab
MED-III None 1961 Crypto Estab
MED-II None 1956 Crypto Estab
WA-I None 1961 Crypto Estab
NA-ET3 Cape Cod to Cape Hatteras 1920 Crypto Estab
CAR-VII Cape Hatteras to Mid-East Florida 1973 Crypto Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1971 Crypto Estab
CASP Caspian Sea 0 Crypto Estab
CIO-II None 0 Crypto Estab
NWP-4b None 1944 Crypto Estab
SA-II None 1947 Crypto Estab
NEP-V Northern California to Mid Channel Islands 1967 Def Estab
CIO-I None 0 Crypto Estab
NEP-VI Pt. Conception to Southern Baja California 2004 Def Estab
M130 Chesapeake Bay 1916 Crypto Estab
P090 San Francisco Bay 1967 Def Estab
S190 Indian River 1975 Crypto Estab
P080 Monterey Bay 2003 Def Estab
P010 Tijuana Estuary 2004 Def Estab
S010 Albemarle Sound 1973 Crypto Estab
S080 Charleston Harbor 1973 Crypto Estab
G170 West Mississippi Sound 1971 Crypto Estab
G210 Terrebonne/Timbalier Bays 1972 Crypto Estab
G200 Barataria Bay 1972 Crypto Estab
G160 East Mississippi Sound 1975 Crypto Estab
G260 Galveston Bay 2003 Crypto Estab
G310 Corpus Christi Bay 2003 Crypto Estab
P093 _CDA_P093 (San Pablo Bay) 2004 Def Estab
NEA-V None 1965 Def Estab
CIO-III None 1908 Crypto Estab
EAS-I None 0 Crypto Estab
NWP-4a None 2016 Crypto Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
4300 Cowles 1930; Osburn 1932 1920 1920-01-01 James Island Crypto 38.4556 -76.2425
4303 Cowles 1930; Osburn 1932 1920 1920-01-01 off Cape Charles City Crypto 37.2663 -76.0280
4304 Cowles 1930; Osburn 1932 1920 1920-01-01 off New Point Comfort Crypto 37.3019 -76.2778
4305 Cowles 1930; Osburn 1932 1920 1920-01-01 off Tangier Island Crypto 37.8283 -75.9922
4306 Thompson 1993 1993 1993-01-01 Surry Power Station (Hog Island) Crypto 37.1811 -76.6783
4307 Abbe 1987 1987 1987-01-01 Calvert Cliffs Nuclear Power Plant Crypto 38.4347 -76.4417
4308 Calder 1966 1966 1966-01-01 Norfolk Naval Base Crypto 36.9533 -76.3150
4309 Ruiz et al., unpublished data 1995 1995-01-01 Gloucester Point Crypto 37.2456 -76.5050
4310 Cory 1967 1964 1964-01-01 Chalk Point Crypto 38.5400 -76.6831
4311 Cory 1967 1964 1964-01-01 Solomons Crypto 38.3183 -76.4544
4312 Banta and Backus 1991 1991 1991-01-01 below Little Falls, Washington Crypto 38.9301 -77.1144
4313 Ruiz et al., unpublished data 1995 1995-01-01 Rhode River Crypto 38.8647 -76.5150
4314 Ruiz et al., unpublished data None 1995-01-01 None Crypto 39.3893 -76.3569
4315 Dean and Bellis 1975 1973 1973-01-01 Whichard Beach Crypto 35.5042 -77.0233
4316 Dean and Bellis 1975 1973 1973-01-01 Point of Narrows Crypto 35.3653 -76.4242
4317 Dean and Bellis 1975 1972 1973-01-01 Hills Point Crypto 35.4703 -76.9853
4319 Calder and Maturo 1978 1973 1973-10-01 Cooper River Crypto 33.2261 -79.4881
4320 Winston 1982 1982 1975-01-01 Link Port, Fort Pierce Crypto 27.4464 -80.3258
4321 Poirrier and Mulino 1977 1971 1971-10-01 Lake Ponchartrain Causeway, south end Crypto 30.0788 -90.1440
4322 Poirrier and Mulino 1977 1975 1975-10-01 Ocean Springs Crypto 30.3913 -88.8109
4323 Poirrier and Mulino 1977 1974 1974-09-01 Madisonville Crypto 30.3766 -90.1606
4324 Poirrier and Mulino 1977 1975 1975-08-01 I-10 causeway, near Point aux herbes Crypto 30.1544 -89.8542
4325 de Rivera et al. 2005 2004 2003-08-01 Model Marsh, Tijuana River Def 32.5481 -117.1231
4326 de Rivera et al. 2005 2003 2003-08-01 San Diego Def 32.5597 -117.1066
4327 de Rivera et al. 2005 2003 2003-08-01 Moss Landing, North Def 36.8135 -121.7881
4329 Carlton 1979, Cohen and Carlton 1995 1967 1967-01-01 Oakland Def 37.8072 -122.2503
4330 Cohen et al. 2004) 2004 2004-05-25 Petaluma River Turning Basin Def 38.1127 -122.5014
767860 Ruiz et al., 2015 2011 2011-09-27 Petaluma Marina, San Francisco Bay, CA, California, USA Def 38.2304 -122.6136
767940 Ruiz et al., 2015 2011 2011-09-26 Pittsburg Marina, San Francisco Bay, CA, California, USA Def 38.0346 -121.8829

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