Description
Family- Assignments to families vary greatly among authors. Tenellia adspersa (Miniature Aeolis) has been placed in several other families: Tergipedidae ( Eyster 1980; Rosenberg 1995) and Dotoidae (Abbott 1974).
Potentially Misidentified Species - Tenellia fuscata lacks a penial stylet; present in T. adspersa and has a hermaphoditic valve; absent in T. adspersa (Marcus 1972). Vogel (1977) reported a third undescribed Tenellia sp. from the Eastern Shore of VA with different body proportions and radular pattern. Most records of T. adspersa in the Western Atlantic are from warmer, often estuarine waters (Brazil-DE); while records of T. fuscata are most frequently from more northern coastal waters (MA-VA) (Vogel 1977; Rosenberg 1995), but considerable overlap occurs. Tenellia adspersa occurs in Great Bay NH (Chester 1997 (identifications verified by K. B. Clark, Chester personal communication 1997), while T. fuscata has been reported from FL (Clark 1995). Careful morphological examination and, possibly, molecular analysis, may be needed to determine the distribution of the species of Tenellia spp.
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus |
|---|---|---|---|---|---|
| Animalia | Mollusca | Gastropoda | Nudibranchia | Cuthonidae | Tenellia |
Synonyms
Invasion History
Chesapeake Bay Status
| First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
|---|---|---|---|---|---|---|---|
| 1972 | Established | Stable | Cryptogenic | Regular Resident | Eastern Atlantic | Eastern Atlantic | Shipping(Ballast Water,Fouling Community) |
History of Spread
Tenellia adspersa (Miniature Aeolis) is now widely distributed around the world, and has doubtless been spread by shipping (Roginskaya 1970; Thompson and Brown 1984) . It is known in the Atlantic from Europe (Norway-Mediterranean), the sea of Azov [invaded 1963 (Roginskaya 1970)], Brazil, and the east coast of the United States (NH-SC) (Marcus 1972; Vogel 1977; Eyster 1979; Chester 1996). In the Pacific, it is an apparent invader in San Francisco Bay (first collected 1953) (Cohen and Carlton 1995) and Japan (Roginskaya 1970).
Its status in the Northwest Atlantic is complicated by confusion with the very similar T. fuscata which overlaps in range and habitat (Marcus 1972; Vogel 1977). T. fuscata is generally considered a cold-water form, with most records from MA-MD (Abbott 1974; Franz 1968; Vogel 1977), but there is one from Indian River Lagoon ; FL (Clark 1995). Tenellia adspersa is regarded as a warm-water form, records from Norway come from areas with Gulf-Stream influence (Lofoten Islands), and in Great Britain, it is known only from the southernmost coast (Thompson and Brown 1984). Vogel's Chesapeake data (1977) data suggests that T. adspersa ranges into lower salinities (average 12.5 ppt) than T. fuscata (14.5-30). Records of 'Tenellia ventilabrum' from MA-DE (Abbott 1974) may refer to either T. adspersa or T. fuscata, since these species were often lumped (Marcus 1972). The first verified record of T. adspersa in the Northwest Atlantic appears to be from Chesapeake Bay (Marcus 1972). All of the small number of our fouling-plate specimens, examined closely by Terence Gosliner, were T. adspersa (Ruiz et al., unpublished data).
East Coast Records are summarized below:
Brazil - Tenellia adspersa was collected before 1955 (Thompson and Brown 1984).
South Carolina - Tenellia adspersa was collected from North Inlet, by 1976, as T. pallida (Eyster 1979).
Chesapeake Bay - Cory (1967) collected Tenellia sp. from fouling plates. The first published, verified record of T. adspersa was by Marcus (1972). Tenellia fuscata was reported from Bay and Atlantic-side inlets and an unidentifed Tenellia sp. from the Atlantic side of the VA Eastern Shore (Vogel 1977).
Delaware-Barnegat Bays (NJ)- Tenellia fuscata was found but not T. adspersa (Franz 1968).
Gulf of Maine - Tenellia fuscata was described by Gould (1870) from Charles River, but he did not describe key characters separating T. fuscata and T. adspersa, so this could have been T. adspersa (Franz 1968). Both T. adspersa (Chester 1996) and T. fuscata (Gaulin et al. 1986) have been reported from Great Bay NH but specimens identified by K. B. Clark were T. adspersa (Chester personal communication 1997).
Chesapeake Bay records:
Lower Bay - Verified specimens of T. adspersa were collected from Dorchester County, MD, Manokin River 'and many other places on hydroids' (Marcus 1972), from Cape Charles City, VA, Cherrystone inlet (Vogel 1977), Vogel reported a mixture of T. fuscata and T. adspersa from Gloucester Point VA and the mouth of the Rappahannock River Vogel (1977). Ruiz et al. (unpublished) found only T. adspersa on fouling plates, as did Thompson (1993) at the Surry Nuclear Power Plant (Hog Island), on the James River.
Patuxent River - Tenellia sp. [Treated as mixed T. adspersa and T. fuscata by Vogel (1977)] were collected from Lower Marlboro to Solomons (Cory 1964; Vogel 1977).
Upper Bay - Tenellia sp. [Treated as mixed T. adspersa and T. fuscata by (Vogel 1977)] were collected from Deal and Kent Point MD (Vogel 1977); Baltimore Harbor; and Middle River (Ruiz et al. unpublished). Ruiz et al. (unpublished) found only T. adspersa on fouling plates.
History References - Abbott 1974; Chester 1996; Cory 1967; Eyster 1979; Franz 1968; Gaulin et al. 1986; Gould 1870; Roginskaya 1970; Thompson and Brown 1984; Vogel 1977
Invasion Comments
Ecology
Environmental Tolerances
| For Survival | For Reproduction | |||
|---|---|---|---|---|
| Minimum | Maximum | Minimum | Maximum | |
| Temperature (ºC) | ||||
| Salinity (‰) | 3.0 | 40.0 | 3.0 | 40.0 |
| Oxygen | ||||
| pH | ||||
| Salinity Range | oligo-poly |
Age and Growth
| Male | Female | |
|---|---|---|
| Minimum Adult Size (mm) | 5.0 | 5.0 |
| Typical Adult Size (mm) | 6.0 | 6.0 |
| Maximum Adult Size (mm) | 7.0 | 7.0 |
| Maximum Longevity (yrs) | ||
| Typical Longevity (yrs | 0.1 | 0.1 |
Reproduction
| Start | Peak | End | |
|---|---|---|---|
| Reproductive Season | |||
| Typical Number of Young Per Reproductive Event |
|||
| Sexuality Mode(s) | |||
| Mode(s) of Asexual Reproduction |
|||
| Fertilization Type(s) | |||
| More than One Reproduction Event per Year |
|||
| Reproductive Startegy | |||
| Egg/Seed Form |
Impacts
Economic Impacts in Chesapeake Bay
High abundances of Tenellia sp. have been reported on fouling plates near power plants in the Chesapeake (Cory 1967; Abbe 1987). Tenellia adspersa might have some benefical impact on fouling in cooling systems if its predation reduced biomasses of hydroids such as Garveia and Cordylophora. However, at least for Cordylophora, polyp regeneration is rapid. Cordylophora in Great Bay NH developed a denser colony form when exposed to T. adspersa (identified as T. fuscata in this paper, Chester, personal communication 1997), which may have caused more larvae to be eaten on settlement. High densities of T. adspersa would be needed to 'swamp' Cordylophora or other hydroids (Gaulin et al. 1986).
References - Abbe 1987; Chester, personal communication 1997; Cory 1967; Gaulin et al. 1986
Economic Impacts Outside of Chesapeake Bay
Tenellia adspersa (Miniature Aeolis) could be possibly beneficial due to its predation on fouling hydroids, as discussed for Chesapeake Bay.
Ecological Impacts on Chesapeake Native Species
Tenellia adspersa (Miniature Aeolis) is potentially an important predator on native hydroids (Obelia sp.; Bougainvillea sp. and others) (Roginskaya 1970; Thompson and Brown 1984; Vogel 1977). Because of the difficulty of separating it from the native T. fuscata, its relative abundance and impact in the Chesapeake Bay is unknown. Competition with T. fuscata is possible but has not been documented.
References - Roginskaya 1970; Thompson and Brown 1984; Vogel 1977
Ecological Impacts on Other Chesapeake Non-Native Species
Tenellia adspersa (Miniature Aeolis) is potentially an important predator on introduced hydroids [Garveia franciscana (Rope Grass Hydroid); Cordylophora caspia (Freshwater Hydroid). Because of the difficulty of separating it from T. fuscata, T. adspersa's relative abundance and impact in the Chesapeake Bay is unknown. With hydroids and nudibranchs from Great Bay NH, exposure to T. adspersa (identified in the paper as T. fuscata; Chester, personal communication 1997) chemical cues and predation caused an alteration of C. caspia's growth form, resulting in a greater density of hydranths. This could limit later settlement of T. adspersa's larva, due to predation. Tenellia adspersa predation on C. caspia thus seems to have complex effects; small numbers of Tenellia adspersa might actually increase C. caspia biomass (Gaulin et al. 1986).
References - Gaulin et al. 1986; Chester 1996; Chester personal communication 1997
References
Abbe, George R. (1987) Epifauna, In: Heck, Kenneth L.(Eds.) Ecological studies in the middle reach of Chesapeake Bay- Calvert Cliffs. , Berlin. Pp. 82-91Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America, , Davis. Pp. 1-904
Chester, Charles M. (1996) The effect of adult nutrition on the reproduction and development of the estuarine nudibranch, Tenellia adspersa (Nordmann, 1845), Journal of Experimental Marine Biology and Ecology 198: 113-130
Clark, Kerry B. (1995) Rheophilic/oligotrophic lagoonal communities through the eyes of slugs (Mollusca: Opisthobranchia), Bulletin of Marine Science 57: 242-251
Cohen, A.N.; Carlton, J.T.; Fountain, M.C. (1995) Introduction, dispersal and potential impacts of the green crab Carcinus maenas in San Francisco Bay, California., Marine Biology 122: 225-237
Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, , Washington DC, Silver Spring MD.. Pp.
Cory, Robert L. (1967) Epifauna of the Patuxent River Estuary, Chesapeake Science 8: 71-89
Eyster, L. S. (1979) Reproduction and developmental variability in the Opisthobranch Tenellia pallida, Marine Biology 51: 133-140
Eyster, Linda S. (1980) Distribution and reproduction of some shell-less opisthobranchs from South Carolina, Bulletin of Marine Science 30: 580-599
Franz, David R. (1968) Occurrence and distribution of New Jersey Opisthobranchia, Nautilus 82: 7-12
Gaulin, Gary; Dill, Lauren; Beaulieu, Juli; Harris, Larry G. (1986) Predation-induced changes in growth form in a nudibranch hydroid association., Veliger 28: 389-393
Gould, Augustus A. (1870) Report of the Invertebrata of Massachusetts, Comprising the Mollusca, , Boston. Pp.
Marcus, Eveline du Bois Reymond (1972) Notes on some opisthobranch gastropods from the Chesapeake Bay, Chesapeake Science 13: 300-317
Marcus, Eveline du Bois Reymond (1977) An annotated checklist of the western Atlantic warm water opisthobranchs, Journal of Molluscan Studies Supplement: 1-22
Roginskaya, I. S. (1970) Tenellia adspersa, a nudibranch new to the Azov Sea, with notes on its taxonomy and ecology, Malacological Review 3: 167-174
1995-2023 Malacolog 4.1. http://www.acnatsci.org
Thompson, Michelle Lynne (1993) Dynamics of an oligohaline, macrofaunal, fouling community., , Williamsburg VA. Pp.
Thompson, T. E.; Brown, G. H. (1984) Biology of Opisthobranch Molluscs, Vol. 2., , London. Pp.
Vogel, Rosalie M. (1977) Shell-less opisthobranchs of Virginia and Maryland, , Williamsburg, VA.. Pp.