The geographical distribution of the Rissoidae in the Atlantic Ocean and Mediterranean Sea was compiled and is up-to-date until July 2011. All species were classified according to their mode of larval development (planktotrophic and nonplanktotrophic), and bathymetrical zonation (shallow species—those living between the intertidal and 50 m depth, and deep species—those usually living below 50 m depth). 542 species of Rissoidae are presently reported to the Atlantic Ocean and the Mediterranean Sea, belonging to 33 genera. The Mediterranean Sea is the most diverse site, followed by Canary Islands, Caribbean, Portugal, and Cape Verde. The Mediterranean and Cape Verde Islands are the sites with higher numbers of endemic species, with predominance of
Rapoport’s latitudinal rule relates geographical distribution with latitude [
Although studies relating biological diversity with latitude usually use higher taxonomical categories, recent papers restricted to checklists of marine molluscs have been used to address this issue [
The Rissoidae are a family of small-sized, marine to brackish-water gastropod molluscs. This very diverse family was taxonomically reviewed by Wenz [
Published information about the Atlantic and Mediterranean Rissoidae is vast and is scattered among a wide variety of journals but, with a few exceptions, these studies are typically geographically localized. Many species descriptions are usually based on shell morphology and on only a few specimens, most of them dead shells. At present, there is a lack of a background scenario of the geographical distribution for this family in the Atlantic and in the Mediterranean. No phylogeny has been established for this family.
To our knowledge, this is the first attempt to summarize present information about the geographic distributional pattern of this family in the Atlantic Ocean and the Mediterranean Sea, with the purpose of identifying the biotic similarities between areas.
The geographical distribution of the Rissoidae in the Atlantic Ocean and Mediterranean Sea was compiled through an exhaustive search of the primary literature and is up to date until July 2011. The following sites and references were considered: ARC: Arctic: above 75° N: Warén [ GRE: Greenland, western shores of Baffin Island, Baffin Bay, Davis Strait, and Labrador Sea: Bouchet and Warén [ ICE: Iceland: Warén [ SCA: Scandinavia: Norway Sea, Skagerrak and Kattegat, Baltic Sea and Faroe Islands: Fretter and Graham [ BRI: British Isles: Smith [ POR: western Atlantic Iberian façade (from Cabo Vilán, western Galician shores, down to Cape São Vicente) and southern shores of Algarve, Portugal): Nobre [ MED: Mediterranean: Nordsieck [ AZO: Azores: Watson [ LUS: Lusitanian group of seamounts (a chain of seamounts located between Portugal and Madeira): Gorringe, Josephine, Ampère, Seine: Ávila and Malaquias [ MET: Meteor group of seamounts (located about 600 km south of the Azores): Great Meteor, Irving, Atlantis, Hyères, Plato, Tyro, Cruiser: Gofas [ MAD: Madeira, Porto Santo and Desertas Islands, Nobre [ SEL: Selvagens Islands: Verduin [ CAN: Canary Islands: van Aartsen [ CAP: Cape Verde archipelago: Rolán [ STH: Saint Helena Island: Smith [ TRS: Tristão da Cunha Island: Worsfold et al. [ WAF: West African shores—Atlantic Morocco, from Straits of Gibraltar south, Western Sahara, and Mauritania, Cape Verde (Senegal): Verduin [ ANG: Angola: Rolán and Ryall [ NSC: New Scotia biogeographical province—Atlantic shores of USA, between Newfoundland (50° N) and Cape Cod (42° N): MALACOLOG, VIR: Virginian biogeographical province CRL: Carolinian biogeographical province–Atlantic shores of USA, between Cape Hatteras, North Carolina (35° N) and Cape Canaveral (28°30′ N): Rex et al. [ TRO: Tropical biogeographical province (from now on generically designated as “Caribbean”)—Atlantic shores of USA, south of Cape Canaveral (28°30′ N), including western and eastern shores of Florida, Gulf of Mexico (Louisiana and Texas shores, as well as Yucatan Peninsula, México), Bahamas, Caribbean Sea, south to Cabo Frio (Brazil) (23°S): Dall [ BRA: Biogeographical province of Brazil (this includes the Paulista and Patagonic Provinces SSA: southeast of South America—biogeographical province of Malvinas ( ANT: Antarctic—from 60°S south, including South Orkney Islands (Signy Island), South Shetland islands, Antarctic Peninsula and Weddell Sea: Ponder [
We have also consulted other bibliographical sources, with a wider systematical or geographical subject, such as Babio and Thiriot-Quiévreux [
The bathymetrical zonation considers shallow species (those living between the intertidal and 50 m depth) and deep species (those usually living below 50 m depth). The choice of the threshold at 50 m depth is related with the following reasons: (i) algal species to which Rissoidae are very often associated are rare below 50 m depth; (ii) direct sampling by scuba-diving is more frequent in waters less than 50 m depth; (iii) in waters deeper than 50 m depth, usually the samplings are obtained via indirect methodologies (grabs, most often).
The complete database was last updated in October 2011 and is available from the authors upon request.
All species were classified according to their mode of larval development and bathymetrical zonation. Rissoids lay ovigerous capsules in the substrate that originate larvae with different modes of larval development. The extension of the larval phase reflects on the capabilities of dispersal and this has important ecological and historical biogeographical implications, related with the geographical distribution of the species. Two types of larval development were considered: planktotrophic (with a free
Rosen and Smith [
Four species considered as Lessepsian and thus reported to the Mediterranean were removed from the initial database:
The analysis of the historical relationships between the selected areas was complemented by using the following formulas (
Rissoidae family comprises 47 valid genera, some with a worldwide distribution (
Five hundred and forty-two species of Rissoidae are presently reported to the Atlantic Ocean and the Mediterranean Sea, belonging to 33 genera. Six genera are represented by a single species:
The Mediterranean Sea is the most diverse site, with 160 species of Rissoidae, followed by Canary Islands (89 species), Caribbean (77), Portugal (74), and Cape Verde (67). The lowest diversity sites are the Carolinian Province (18 species), Greenland (16), Arctic (13), Angola (11), New Scotia Biogeographical Province (10), Antarctic (8), Virginian Biogeographical Province, Tristan da Cunha Island, and Brazil (all with just 7 species, Table
Number of Rissoid species, by genus in the Atlantic Ocean and in the Mediterranean Sea. ARC: Arctic; GRE: Greenland; ICE: Iceland; SCA: Scandinavia; BRI: British Isles; POR: Portugal; MED: Mediterranean Sea; LUS: Lusitanian seamounts; MET: Meteor seamounts; AZO: Azores; MAD: Madeira, Porto Santo and Desertas; SEL: Selvagens Islands; CAN: Canary Islands; CAP: Cape Verde; WAF: west-African coast; ANG: Angola; NSC: New Scotia biogeographic province; VIR: Virginian biogeographic province; CRL: Carolinian biogeographic province; TRO: Tropical biogeographic province (Caribbean); BRA: Brazil; STH: Santa Helena; TRS: Tristan da Cunha; SSA: southern South-America; ANT: Antarctic.
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
4 | 7 | 10 | 12 | 10 | 30 | 74 | 10 | 9 | 19 | 22 | 13 | 28 | 25 | 29 | 5 | 1 | 1 | 2 | 21 | 1 | 1 | ||||
1 | 1 | 1 | |||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||||
1 | 1 | 2 | 3 | 1 | 4 | 5 | 2 | 1 | |||||||||||||||||
2 | 2 | 1 | 1 | 1 | |||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 2 | 9 | ||||||||||||||||||
1 | 1 | 1 | 7 | 1 | 1 | 8 | 6 | 10 | 6 | 3 | 1 | ||||||||||||||
2 | |||||||||||||||||||||||||
3 | 2 | 1 | 1 | 3 | 2 | ||||||||||||||||||||
1 | 1 | 1 | |||||||||||||||||||||||
2 | 5 | 2 | 1 | 1 | 1 | ||||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | 1 | 2 | 1 | 6 | 1 | 7 | 7 | 10 | 2 | 1 | |||||||||||||||
4 | 1 | ||||||||||||||||||||||||
2 | 2 | 2 | 1 | 2 | 2 | 1 | 1 | 2 | 1 | 1 | |||||||||||||||
3 | 5 | 9 | 3 | 2 | 3 | 7 | 1 | 2 | 1 | 5 | 4 | 2 | 2 | 6 | 22 | 7 | |||||||||
1 | 2 | ||||||||||||||||||||||||
1 | 1 | 1 | 2 | ||||||||||||||||||||||
1 | |||||||||||||||||||||||||
8 | |||||||||||||||||||||||||
1 | 3 | 1 | |||||||||||||||||||||||
1 | 2 | 1 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | ||||||||||||||
2 | 2 | 7 | 11 | 1 | 2 | 1 | 3 | 5 | 1 | 2 | 1 | 1 | 1 | 1 | |||||||||||
3 | 4 | 12 | 26 | 1 | 2 | 7 | 5 | 15 | 1 | 2 | 2 | ||||||||||||||
1 | 3 | 1 | 1 | 2 | 1 | 1 | 4 | 18 | 2 | ||||||||||||||||
1 | 1 | 1 | 1 | 1 | |||||||||||||||||||||
1 | 26 | 1 | 4 | 9 | 2 | 5 | |||||||||||||||||||
1 | 6 | 18 | 5 | 3 | 1 | 6 | 1 | 1 | |||||||||||||||||
1 | 3 | ||||||||||||||||||||||||
2 | |||||||||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | 2 | 1 | 2 | 1 | 1 | 2 | 6 | ||||||||||||||||||
Total of Rissoidae species | 13 | 16 | 25 | 30 | 27 | 74 | 160 | 27 | 26 | 38 | 63 | 38 | 89 | 67 | 50 | 11 | 10 | 7 | 18 | 77 | 7 | 20 | 7 | 27 | 8 |
The genera
The Mediterranean and Cape Verde Islands are the sites with higher numbers of endemic species (71 and 58, resp.), with predominance of
Number of endemic Rissoidae, other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2 | 1 | 37 | 1 | 7 | 10 | 3 | 2 | 7 | 20 | 5 | 1 | 19 | 1 | ||||||||||||
1 | 1 | 2 | 1 | ||||||||||||||||||||||
1 | 1 | ||||||||||||||||||||||||
1 | 1 | ||||||||||||||||||||||||
1 | 2 | 9 | |||||||||||||||||||||||
3 | 1 | 1 | 1 | 6 | 1 | ||||||||||||||||||||
2 | |||||||||||||||||||||||||
3 | 2 | ||||||||||||||||||||||||
1 | |||||||||||||||||||||||||
5 | 1 | 2 | 1 | 4 | 1 | 1 | |||||||||||||||||||
4 | 1 | ||||||||||||||||||||||||
1 | 1 | 1 | |||||||||||||||||||||||
1 | 2 | 6 | 1 | 1 | 2 | 6 | 14 | 2 | |||||||||||||||||
1 | |||||||||||||||||||||||||
1 | |||||||||||||||||||||||||
8 | |||||||||||||||||||||||||
2 | 1 | ||||||||||||||||||||||||
1 | |||||||||||||||||||||||||
3 | 1 | 1 | 1 | 1 | |||||||||||||||||||||
11 | 3 | 1 | 2 | ||||||||||||||||||||||
1 | 1 | 1 | 13 | ||||||||||||||||||||||
1 | 26 | 1 | 5 | 4 | |||||||||||||||||||||
9 | 3 | 1 | 1 | 1 | |||||||||||||||||||||
2 | |||||||||||||||||||||||||
2 | |||||||||||||||||||||||||
1 | 1 | 4 | |||||||||||||||||||||||
Total of endemic Rissoidae | 2 | 1 | 3 | 1 | 0 | 3 | 71 | 10 | 20 | 17 | 8 | 3 | 17 | 58 | 12 | 0 | 0 | 0 | 3 | 57 | 1 | 18 | 6 | 18 | 3 |
Total of Rissoidae species | 13 | 16 | 25 | 30 | 27 | 74 | 160 | 27 | 26 | 38 | 63 | 38 | 89 | 67 | 50 | 11 | 10 | 7 | 18 | 77 | 7 | 20 | 7 | 27 | 8 |
15.4 | 6.3 | 12.0 | 3.3 | 0.0 | 4.0 | 44.4 | 37.0 | 76.9 | 44.7 | 12.7 | 7.9 | 19.1 | 86.6 | 24.0 | 0.0 | 0.0 | 0.0 | 16.7 | 74.0 | 14.3 | 90.0 | 85.7 | 66.7 | 37.5 |
In spite of the large number of rissoids at Selvagens (38 species), a large number of species are shared with Canaries (30) and Madeira (27) (Table
Number of shared Rissoidae species, other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
13 | |||||||||||||||||||||||||
10 | 16 | ||||||||||||||||||||||||
8 | 13 | 25 | |||||||||||||||||||||||
7 | 9 | 16 | 30 | ||||||||||||||||||||||
2 | 4 | 11 | 22 | 27 | |||||||||||||||||||||
0 | 1 | 7 | 18 | 22 | 74 | ||||||||||||||||||||
0 | 0 | 6 | 17 | 21 | 62 | 160 | |||||||||||||||||||
0 | 0 | 2 | 5 | 6 | 11 | 9 | 27 | ||||||||||||||||||
0 | 0 | 1 | 1 | 1 | 1 | 1 | 2 | 26 | |||||||||||||||||
0 | 0 | 3 | 5 | 6 | 8 | 7 | 5 | 5 | 38 | ||||||||||||||||
0 | 0 | 4 | 5 | 8 | 17 | 17 | 7 | 1 | 12 | 63 | |||||||||||||||
0 | 0 | 0 | 0 | 1 | 11 | 11 | 4 | 0 | 3 | 27 | 38 | ||||||||||||||
1 | 2 | 7 | 14 | 17 | 32 | 36 | 7 | 2 | 9 | 42 | 30 | 89 | |||||||||||||
1 | 0 | 2 | 3 | 4 | 5 | 5 | 2 | 0 | 3 | 4 | 1 | 4 | 67 | ||||||||||||
0 | 0 | 3 | 7 | 9 | 18 | 22 | 5 | 0 | 4 | 12 | 6 | 17 | 7 | 50 | |||||||||||
0 | 0 | 1 | 2 | 2 | 3 | 3 | 0 | 0 | 2 | 2 | 0 | 2 | 3 | 11 | 11 | ||||||||||
4 | 5 | 6 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 2 | 0 | 0 | 0 | 10 | |||||||||
2 | 3 | 4 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 2 | 0 | 0 | 0 | 7 | 7 | ||||||||
0 | 0 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 2 | 0 | 2 | 0 | 0 | 0 | 1 | 1 | 18 | |||||||
0 | 0 | 1 | 1 | 1 | 2 | 3 | 1 | 2 | 2 | 3 | 0 | 3 | 0 | 1 | 0 | 1 | 1 | 15 | 77 | ||||||
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 5 | 7 | |||||
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 20 | ||||
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7 | |||
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 27 | ||
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 8 |
Most of the 542
Bathymetric zonation of the Rissoidae. Lit—littoral species (usually living at depths less than 50 m depth); deep—deep species (usually living at depths higher than 50 m depth). Other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | |||||||||||||||
lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | |
2 | 4 | 7 | 2 | 8 | 5 | 5 | 17 | 13 | 50 | 20 | 9 | 6 | 11 | 8 | 13 | 9 | 10 | 2 | 17 | 11 | 17 | 8 | ||||||
1 | 1 | |||||||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||||||||
1 | 1 | 2 | ||||||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||||||||||||
1 | 1 | 1 | 6 | 1 | 1 | 7 | 6 | 9 | 1 | 6 | ||||||||||||||||||
1 | ||||||||||||||||||||||||||||
1 | ||||||||||||||||||||||||||||
2 | 2 | 5 | 1 | 1 | 1 | |||||||||||||||||||||||
1 | 1 | 2 | 1 | 5 | 1 | 6 | 7 | 1 | 10 | |||||||||||||||||||
1 | 1 | 1 | ||||||||||||||||||||||||||
1 | 1 | 2 | 1 | 3 | 1 | 1 | 1 | 2 | 3 | 3 | 1 | 1 | 1 | 1 | 3 | 1 | ||||||||||||
1 | 2 | |||||||||||||||||||||||||||
1 | 1 | 1 | ||||||||||||||||||||||||||
8 | ||||||||||||||||||||||||||||
2 | 2 | 1 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | ||||||||||||||||||
1 | 1 | 5 | 1 | 9 | 2 | 1 | 1 | 1 | 1 | 2 | 2 | 1 | ||||||||||||||||
3 | 5 | 12 | 23 | 2 | 7 | 5 | 14 | 1 | ||||||||||||||||||||
1 | 2 | 1 | 1 | 2 | ||||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | ||||||||||||||||||||||||
1 | 20 | 6 | ||||||||||||||||||||||||||
1 | 6 | 17 | 5 | 3 | 1 | 6 | ||||||||||||||||||||||
1 | ||||||||||||||||||||||||||||
1 | 2 | 1 | 2 | 1 | ||||||||||||||||||||||||
Total number of Rissoidae | 2 | 5 | 2 | 6 | 2 | 12 | 11 | 13 | 17 | 8 | 51 | 20 | 118 | 28 | 0 | 26 | 0 | 21 | 24 | 13 | 43 | 16 | 33 | 5 | 66 | 19 | 50 | 16 |
WAF | ANG | TRS | STH | NSC | VIR | CRL | TRO | BRA | SSA | ANT | ||||||||||||
lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | lit | deep | |
18 | 11 | 6 | 1 | 10 | 3 | 1 | ||||||||||||||||
1 | ||||||||||||||||||||||
1 | 1 | 1 | 1 | |||||||||||||||||||
3 | 1 | 1 | 3 | 4 | 2 | |||||||||||||||||
4 | 2 | |||||||||||||||||||||
1 | 2 | 1 | ||||||||||||||||||||
1 | ||||||||||||||||||||||
1 | 1 | 1 | 1 | |||||||||||||||||||
1 | ||||||||||||||||||||||
1 | 1 | 1 | ||||||||||||||||||||
1 | 3 | |||||||||||||||||||||
2 | 4 | 1 | 1 | 1 | 1 | 1 | 14 | 4 | 5 | |||||||||||||
2 | ||||||||||||||||||||||
1 | 3 | 1 | ||||||||||||||||||||
1 | ||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | ||||||||||||||||||
1 | 2 | |||||||||||||||||||||
1 | 1 | 4 | 13 | |||||||||||||||||||
1 | 1 | 4 | 8 | 2 | ||||||||||||||||||
1 | 1 | |||||||||||||||||||||
1 | 3 | |||||||||||||||||||||
2 | ||||||||||||||||||||||
1 | 2 | 4 | ||||||||||||||||||||
Total number of Rissoidae | 29 | 19 | 8 | 1 | 2 | 5 | 9 | 1 | 2 | 4 | 2 | 4 | 11 | 5 | 42 | 15 | 2 | 2 | 18 | 5 | 6 | 0 |
It was possible to infer the mode of larval development of 450 out of the 542 rissoid species, with 375 nonplanktotrophic species, and 75 planktotrophic species (Table
Mode of larval development of the Rissoidae: np: nonplanktotrophic species; p: planktotrophic species, other abbreviations as in Table
Total number of rissoids | |||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ARC | np | 4 | 2 | 1 | 3 | 3 | 13 | ||||||||||||||||||||||||||||
p | 0 | ||||||||||||||||||||||||||||||||||
GRE | np | 7 | 2 | 2 | 5 | 16 | |||||||||||||||||||||||||||||
p | 0 | ||||||||||||||||||||||||||||||||||
ICE | np | 9 | 1 | 1 | 8 | 1 | 20 | ||||||||||||||||||||||||||||
p | 1 | 1 | 1 | 1 | 4 | ||||||||||||||||||||||||||||||
SCA | np | 7 | 1 | 1 | 1 | 2 | 2 | 1 | 15 | ||||||||||||||||||||||||||
p | 5 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 14 | ||||||||||||||||||||||||||
BRI | np | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 9 | ||||||||||||||||||||||||||
p | 7 | 1 | 1 | 1 | 1 | 1 | 2 | 3 | 17 | ||||||||||||||||||||||||||
POR | np | 17 | 1 | 1 | 2 | 1 | 2 | 3 | 2 | 3 | 1 | 6 | 39 | ||||||||||||||||||||||
p | 13 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 5 | 9 | 1 | 35 | |||||||||||||||||||||||
MED | np | 51 | 1 | 2 | 4 | 2 | 5 | 10 | 1 | 17 | 93 | ||||||||||||||||||||||||
p | 17 | 1 | 3 | 1 | 2 | 1 | 1 | 1 | 6 | 12 | 1 | 1 | 1 | 48 | |||||||||||||||||||||
LUS | np | 5 | 1 | 1 | 5 | 6 | 1 | 1 | 20 | ||||||||||||||||||||||||||
p | 5 | 1 | 1 | 7 | |||||||||||||||||||||||||||||||
MET | np | 9 | 1 | 2 | 8 | 1 | 2 | 1 | 1 | 25 | |||||||||||||||||||||||||
p | 1 | 1 | |||||||||||||||||||||||||||||||||
AZO | np | 17 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 5 | 33 | |||||||||||||||||||||
p | 2 | 1 | 1 | 1 | 5 | ||||||||||||||||||||||||||||||
MAD | np | 20 | 1 | 1 | 1 | 3 | 1 | 7 | 2 | 1 | 2 | 6 | 1 | 3 | 1 | 50 | |||||||||||||||||||
p | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |||||||||||||||||||||||||||
SEL | np | 12 | 1 | 2 | 1 | 7 | 1 | 1 | 4 | 1 | 1 | 1 | 32 | ||||||||||||||||||||||
p | 1 | 1 | 2 | ||||||||||||||||||||||||||||||||
CAN | np | 23 | 1 | 3 | 1 | 10 | 4 | 2 | 2 | 8 | 1 | 4 | 1 | 60 | |||||||||||||||||||||
p | 5 | 1 | 2 | 1 | 1 | 3 | 6 | 1 | 1 | 21 | |||||||||||||||||||||||||
CAP | np | 20 | 1 | 6 | 1 | 1 | 1 | 26 | 1 | 57 | |||||||||||||||||||||||||
p | 5 | 1 | 2 | 1 | 1 | 10 | |||||||||||||||||||||||||||||
WAF | np | 18 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 29 | ||||||||||||||||||||||||
p | 11 | 1 | 1 | 1 | 1 | 2 | 2 | 1 | 1 | 21 | |||||||||||||||||||||||||
ANG | np | 2 | 2 | ||||||||||||||||||||||||||||||||
p | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 9 | |||||||||||||||||||||||||||
NSC | np | 1 | 3 | 4 | 1 | 9 | |||||||||||||||||||||||||||||
p | 1 | 1 | |||||||||||||||||||||||||||||||||
VIR | np | 1 | 2 | 2 | 1 | 6 | |||||||||||||||||||||||||||||
p | 1 | 1 | |||||||||||||||||||||||||||||||||
CRL | np | 1 | 1 | 1 | 1 | 1 | 5 | ||||||||||||||||||||||||||||
p | 1 | 1 | 2 | 3 | 1 | 8 | |||||||||||||||||||||||||||||
TRO | np | 7 | 1 | 1 | 7 | 4 | 3 | 1 | 3 | 27 | |||||||||||||||||||||||||
p | 1 | 1 | 1 | 7 | 3 | 1 | 2 | 16 | |||||||||||||||||||||||||||
BRA | np | 1 | 1 | ||||||||||||||||||||||||||||||||
p | 1 | 1 | 2 | 4 | |||||||||||||||||||||||||||||||
STH | np | 1 | 8 | 9 | |||||||||||||||||||||||||||||||
p | 1 | 1 | 2 | ||||||||||||||||||||||||||||||||
TRS | np | 1 | 1 | ||||||||||||||||||||||||||||||||
p | 0 | ||||||||||||||||||||||||||||||||||
SSA | np | 18 | 2 | 1 | 21 | ||||||||||||||||||||||||||||||
p | 0 | ||||||||||||||||||||||||||||||||||
ANT | np | 6 | 1 | 7 | |||||||||||||||||||||||||||||||
p | 0 |
When the bathymetrical zonation of the rissoid species is analyzed in combination with the modes of larval development, some patterns emerge: most of the shallow nonplanktotrophic species occur in the Mediterranean sea, Cape Verde, and Canary islands, as well as Portugal, the Azores, Madeira archipelago, Selvagens, west African shores, Caribbean, and southeastern South America; shallow planktotrophic rissoid species are much more diverse along the European Atlantic shores, the west-African shores, the Mediterranean, and the Caribbean than in the Atlantic islands, with the exception of Canaries (Table Scandinavia, British Isles, Portugal, Angola, and the Carolinian Province are the only sites with higher numbers of shallow planktotrophic species relative to the number of shallow non-planktotrophs (cf. Tables deep nonplanktotrophic rissoid species are more diverse in the North Atlantic than in the South Atlantic; for instance, there are four such species in the Arctic and no species at all in the Antarctic: these species are also more diverse in the eastern Atlantic than in the western Atlantic shores (Table deep planktotrophic rissoids are restricted to 4 genera,
Number of littoral Rissoidae with nonplanktotrophic mode of larval development, other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
8 | 36 | 10 | 12 | 9 | 14 | 15 | 10 | 2 | 5 | ||||||||||||||
2 | 1 | 1 | 1 | 1 | |||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||||||
1 | 1 | 1 | 1 | 1 | 3 | ||||||||||||||||||
2 | 1 | 3 | 2 | 2 | 6 | ||||||||||||||||||
1 | 1 | ||||||||||||||||||||||
1 | 1 | 6 | 7 | 10 | 1 | ||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 2 | 3 | 1 | 1 | 1 | 3 | 1 | 1 | 13 | 5 | |||||||||
2 | 1 | ||||||||||||||||||||||
1 | 1 | 1 | 4 | 1 | |||||||||||||||||||
3 | 10 | 2 | 6 | 4 | 8 | 1 | |||||||||||||||||
1 | 1 | 5 | |||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | |||||||||||||||||||
20 | 1 | 1 | 4 | ||||||||||||||||||||
1 | 6 | 17 | 5 | 3 | 1 | 4 | 1 | ||||||||||||||||
1 | 3 | ||||||||||||||||||||||
1 | |||||||||||||||||||||||
1 | 1 | 1 | 1 | 1 | 2 | ||||||||||||||||||
Total number of Rissoidae | 3 | 2 | 2 | 4 | 5 | 24 | 74 | 21 | 35 | 27 | 44 | 44 | 14 | 2 | 2 | 2 | 4 | 20 | 0 | 3 | 0 | 16 | 6 |
Number of littoral Rissoidae with planktotrophic mode of larval development, other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2 | 5 | 9 | 12 | 3 | 1 | 1 | 1 | 3 | 2 | 8 | 3 | ||||||||||||||
1 | |||||||||||||||||||||||||
1 | 1 | 1 | 3 | 2 | 1 | 1 | |||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | 1 | 1 | |||||||||||||||||||||||
1 | 1 | 1 | 1 | ||||||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | 1 | ||||||||||||||||||||||||
1 | 1 | 1 | 2 | ||||||||||||||||||||||
1 | 1 | 4 | 5 | 1 | 2 | 1 | |||||||||||||||||||
2 | 3 | 9 | 12 | 1 | 1 | 1 | 6 | 1 | |||||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 2 | 5 | ||||||||||||||||||
3 | 3 | 2 | 1 | ||||||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | 1 | 1 | 1 | 2 | |||||||||||||||||||||
Total number of Rissoidae | 0 | 0 | 0 | 7 | 11 | 27 | 38 | 4 | 0 | 1 | 4 | 2 | 15 | 6 | 15 | 6 | 0 | 0 | 6 | 12 | 2 | 2 | 0 | 0 | 0 |
Number of deep Rissoidae with nonplanktotrophic mode of larval development, other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2 | 4 | 6 | 5 | 3 | 9 | 14 | 4 | 9 | 7 | 8 | 3 | 9 | 5 | 8 | 1 | 1 | |||||||||
1 | 1 | 1 | |||||||||||||||||||||||
1 | 1 | 1 | 2 | 1 | |||||||||||||||||||||
1 | |||||||||||||||||||||||||
1 | 1 | 2 | |||||||||||||||||||||||
1 | 1 | 1 | |||||||||||||||||||||||
2 | 5 | 2 | 1 | 1 | 1 | ||||||||||||||||||||
5 | 1 | ||||||||||||||||||||||||
1 | |||||||||||||||||||||||||
2 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||||||||
8 | |||||||||||||||||||||||||
1 | 2 | 1 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | ||||||||||||||
1 | 1 | 1 | 2 | 1 | 2 | 1 | 1 | 1 | 1 | ||||||||||||||||
1 | |||||||||||||||||||||||||
6 | |||||||||||||||||||||||||
1 | 1 | ||||||||||||||||||||||||
Total number of Rissoidae | 4 | 6 | 10 | 8 | 4 | 15 | 18 | 18 | 25 | 11 | 13 | 5 | 16 | 13 | 15 | 0 | 3 | 3 | 1 | 2 | 0 | 1 | 1 | 1 | 0 |
Number of deep Rissoidae with planktotrophic mode of larval development, other abbreviations as in Table
ARC | GRE | ICE | SCA | BRI | POR | MED | LUS | MET | AZO | MAD | SEL | CAN | CAP | WAF | ANG | NSC | VIR | CRL | TRO | BRA | STH | TRS | SSA | ANT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 3 | 2 | 4 | 5 | 2 | 1 | 1 | 2 | 3 | 3 | |||||||||||||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||||
1 | 1 | 1 | |||||||||||||||||||||||
1 | |||||||||||||||||||||||||
Total number of Rissoidae | 0 | 0 | 2 | 4 | 3 | 5 | 7 | 3 | 1 | 2 | 3 | 0 | 3 | 3 | 4 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
We used PAE separately on the shallow and on the deep rissoid species. After removing all the endemic species (no cosmopolitan species were found), 115 shallow species and 41 deep species of rissoids were analysed with the PAE methodology, using PAUP*.
PAE of the shallow Atlantic and Mediterranean rissoids produced a single most parsimonious tree (
Consensus tree with bootstrap values for the shallow Rissoidae species.
The consensus tree (
Consensus tree with bootstrap values for the deep Rissoidae species, abbreviations as in Table
The results of the analysis of the probable directions of faunal flows (using the
Probable colonization patterns of rissoid fauna in the central west
Probable colonization patterns of rissoid fauna in the Northwest Atlantic. The arrows represent the probable main flux direction of faunas, and the associated numbers represent, for each pair of areas, the higher of the two similarity index values computed as described in the methods, abbreviations as in Table
Probable colonization patterns of rissoid fauna in the South Atlantic. The arrows represent the probable main flux direction of faunas, and the associated numbers represent, for each pair of areas, the higher of the two similarity index values computed as described in the methods, abbreviations as in Table
Probable colonization patterns of rissoid fauna in the Macaronesian islands, Northeast
Probable colonization patterns of rissoid fauna in the Northeast Atlantic. The arrows represent the probable main flux direction of faunas, and the associated numbers represent, for each pair of areas, the higher of the two similarity index values computed as described in the methods, abbreviations as in Table
Probable colonization patterns of rissoid fauna in the Central East-Atlantic. The arrows represent the probable main flux direction of faunas, and the associated numbers represent, for each pair of areas, the higher of the two similarity index values computed as described in the methods, abbreviations as in Table
In the eastern Atlantic, the patterns are more complicated (Figures
It is beyond the scope of this paper to discuss in detail all hypotheses related with Rapoport’s latitudinal rule (e.g., the seasonal variability hypothesis [
Relation between (a) number of rissoids with large bathymetrical range (#sh
Roy et al. [
It is noteworthy to emphasize that the Mediterranean area has more species than expected for similar latitudes (31–43°N) (Figure
By contrast, the low number of rissoids on the Virginian Province (only 7 species) is probably related with the predominance of sandy bottoms on the littoral of this biogeographical Province, and with the multiple lagunar and estuarine systems, which are inhospitable to the benthic algae where many species of these micromolluscs live [
By definition, “a species can be endemic to an area for two different reasons: (a) because it has originated in that place and never dispersed, or (b) because it now survives in only a part of its former wider range” [
In some areas, a few genera went through a speciation process that led to a high number of both species and endemics, for example,
Mironov [
We must stress the high percentage of endemics that occur in the isolated islands of Saint Helena, Tristan da Cunha, and at Cape Verde archipelago (more than 85% of endemics), and also at the Azores (44.7%) thus reinforcing the legislative protective actions that the local governments have implemented in these islands during the recent years. The Cape Verde islands probably received the first rissoids from West-African shores, from where it distances nowadays just about 500 km but must have undergone a long period of isolation, which explains such a high number of endemics. Also, our results (both PAE and
It is a well-known fact that biotic communities in high latitudes are usually rich in nonplanktotrophic species [
It is interesting that the few planktotrophic deep rissoid species are indeed those with higher density and with wider geographical ranges (e.g.,
The first fossil record of the Rissoidae family is from the lower Jurassic of the Tethys Sea [
The ancestral of the Rissoidae presumably had a planktotrophic mode of development [
In the absence of a phylogenetic analyses for this family, one can only speculate that during geological times, the ancestral(s) (either planktotrophic or nonplanktotrophic) dispersed, reached an oceanic island by natural means (see [
As it is not possible to invert the loss of the planktotrophic phase, in a relatively short interval, the planktotrophic ancestral may originate one or several species, by adaptive radiation, each species occupying a different niche. This promotes the increase of the number of nonplanktotrophic species, usually with a restricted range of dispersion (Strahtmann, 1986). Several examples are known from oceanic islands that elucidate the above-mentioned mechanisms: at Madeira, Selvagens, and Canary Islands, the rissoid genera
Currently, we are unable to choose between the following hypotheses: colonization by an ancestral (either planktotrophic or nonplanktotrophic), followed by speciation with adaptive radiation; several independent colonizations, spaced in timed, by an ancestral that originates a different species, without adaptive radiation; both hypotheses above described.
Although many authors postulate a stepping-stone dispersal through the chain of seamounts located between Portugal and Madeira archipelago (Gorringe, Josèphine, Ampère, and Seine), especially during the sea level low stands associated with the Pleistocene glacial periods [
Another interesting feature is the isolation of the Cape Verde archipelago, which is very weakly related with the “
The authors are thankful for Anders Warén, John J. van Aartsen, Emilio Rolán, Willy Segers, Enzo Campani, Constantine Mifsud, and Colin Redfern for their contribution to the mode of development and bathymetry of several Rissoidae species. They also would like to thank an anonymous reviewer and the editor for comments that improved this manuscript. S. P. Ávila was supported by Grant SFRH/BPD/22913/2005 (FCT, Fundação para a Ciência e Tecnologia) of the Portuguese Government, and Synthesys Grants ABC-PD81 and ABC-PD93 (Access to Belgian Collections: European Community, Access to Research Infrastructure action of the Improving Human Research Potential Programme).