In Recent Marine Molluscan Provinces
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PROC. BIOL. SOC. WASH. VOLUME 95, NUN 95(4), 1982, pp. 774-780 PARAPROVINCIALISM: REMNANTS OF Table 1.—Exampl PALEOPROVINCIAL BOUNDARIES Restricted to n IN RECENT MARINE MOLLUSCAN Tegula lividomacul PROVINCES Astraea americana Murex anniae McG Edward J. Petuch Murex cabritii Bern Murex tryoni Hidal Siratus articulatus Abstract.—Paraprovincialism is a biogeographical pattern which takes into ac- Dolicholatirus cayo count Neogene paleoprovincial boundaries that have persisted into the Recent Latirus cariniferus and have been superimposed onto modern provincial arrangements. This pattern Leucozonia ocellatt is manifested as sets of mutually exclusive, congeneric species pairs that abut Oliva reticularis L Olivella mutica (Sa along sharply defined boundary lines. An analysis of the paleontology and paleo- Persicula fluctuata zoogeography of the Caribbean region shows that these Recent species pairs are Prunum carneum ( not true siblings and that their ancestors arose in separate American paleoprov- Enaeta cyllenifornz inces; the southern member having a Gatunian ancestor and the northern member Conus jaspideus G having a Caloosahatchian ancestor. Further analysis shows that these Pliocene Conus magellanicu atla ancestral pairs were true interprovincial siblings and these are referred to as Conus spurius "ancestromas." The paleozoogeography of the ancestromas is preserved in the Recent by descendant species' that have retained the original distributional pat- terns'. Paraprovincialism is found in other provinces, and examples are given for ranges of these the Recent central South Pacific and Indo-Malayasian regions. In areas where bisect the Cari the fossil record is poorly preserved, paraprovincialism may be a useful tool for lap. Some zoo the reconstruction of Neogene provincial boundaries. ribbean into su subregion were insular versus All of these The research that led to the discovery of geographical heterochrony and relict changes in app Pliocene molluscan faunas in the Caribbean (Petuch 1981a, b, 1982) has also in species com brought to light a number of other enigmatic biogeographical patterns in that west and in th region. 'One of the most interesting of these is a previously unstudied phenomenon the Conus jasp that involves a bipartite distributional pattern within many Caribbean gastropod species coexist genera. As is most often the case, the ranges of two congeners are mutually is the only me exclusive and will abut along a very well defined boundary line. When found in to the south.' a province, this pattern occurs in whole suites of species. ample, with 0. Detailed analyses of faunal lists from other molluscan provinces, such as the oblonga being Indo-Pacific, have also revealed similar patterns for many genera. Since these northern Sout mutually exclusive species pairs occur too frequently to be simply random events pairs, Oliva re within a single province, I feel that they represent a real biogeographic phenom- sandy areas o enon that is here referred to as "paraprovincialism." By using examples of para- species are re provincialism in the Recent Caribbean gastropod fauna and linking these to the environments fossil record, I will attempt to explain this problematical pattern of mutually A review of exclusive species pairs and abrupt faunal shifts. listed at the e species pair d Paraprovincialism in the Caribbean Malacologists have generally recognized that the Caribbean Molluscan Prov- ' The Brazilian ince can be divided into northern and southern components, each with indicator species that is n congeners (Warmke and Abbott 1962:3-21, 319-328; Vermeij 1978:227-236). The northern Venezu , 7 0r.. 'Yr.r.t'VettrSt"rt ir'.4.17015EZIErt4 WPMTVILVIMMEteistovwxg-- NICTROMICSIVZTIVW§er- ,OC. WASH. VOLUME 95, NUMBER 4 775 , pp. 774-780 Table 1.—Examples of paraprovincialism in the Caribbean Province. Restricted to northern Caribbean Restricted to southern Caribbean Tegula lividotnaculata (C. B. Adams) Tegula viridula (Gmelin) Astraea americana (Gmelin) Astraea tecta (Lightfoot) Murex anniae McGinty Murex olssoni E. Yokes Murex cabritii Bernardi Murex donmoorei Bulbs Murex tryoni Hidalgo Murex blakeanus E. Vokes Siratus articulatus Reeve Siratus springeri (Bullis) es into ac- Dolicholatirus cayohuesonicus (Sowerby) Dolicholatirus ernesti (Van Jutting) Latirus cariniferus (Lamarck) Latirus bernadensis Bullock the Recent is pattern Leucozonia ocellata Gmelin Leucozonia lineata Usticke Oliva reticularis Lamarck s that abut Oliva oblonga Marrat Olivella mutica (Say) Olive/la petiolita (Duclos) and paleo- Persicula fluctuata (C. B. Adams) Persicula interruptolineata (Megerle) s pairs are Prunum carneum (Storer) Prunum prunum (Gmelin) Enaeta cylleniformis (Sowerby) Enaeta guildingi (Sowerby) paleoprov- Conus jaspideus Gmelin Conus puncticulatus Hwass rn member se Pliocene Conus magellanicus Hwass Comes beddomei Sowerby Conus spurius atlanticus Clench Conus lorenzianus Dillwyn erred to as rved in the utional pat- ranges of these species pairs, some of which are listed here in Table 1, neatly re given for reas where bisect the Caribbean into separate zoogeographic entities with little faunal over- eful tool for lap. Some zoogeographers, such as Briggs (1974:67-76), further divided the Ca- ribbean into subprovinces based on this bipartite pattern. The boundaries of each subregion were thought to have resulted from ecological differences inherent in insular versus continental components of a single province. All of these biogeographic schemes, regardless of their bases. delineate faunal y and relict changes in approximately the same areas. In the Caribbean Sea, an abrupt shift 2) has also in species compositions is found along the Honduras-Nicaragua coastline in the erns in that west and in the Lesser Antilles in the east (Fig. 1). A classic example is seen in henomenon the Conus jaspideus-C. puncticulatus species pair (Walls 1979:817-820). The two in gastropod species coexist on islands from Martinique to the Grenadines, but C. jaspideus Eire mutually is the only member found north of this zone and C. puncticulatus is the only one hen found in to the south.' The Oliva reticularis-0. oblonga species pair is also a good ex- ample, with 0. reticularis being found only north of the Leeward Islands and 0. , such as the oblonga being found only south of these islands and being most prevalent along Since these northern South America. Along with many other northern members of species- ndom events pairs, Oliva reticularis and Conus jaspideus are always found together in shallow, Ihic phenom- sandy areas of the northern Caribbean and Greater Antilles. These sympatric iples of para- species are replaced by Oliva oblonga and Conus puncticulatus in the same these to the environments in the southern Caribbean. of mutually A review of the paleontological literature of the western Atlantic (references listed at the end of Table 2) showed that each member of a Recent Caribbean species pair descended from a separate ancestral species and not from a single Iluscan Prov- I The Brazilian variants of "C. jaspideus - mentioned by Walls actually are a similar, but different, vith indicator species that is not related to this particular species-pair. "Conus jaspideus" from the islands off 27-236). The northern Venezuela are dwarf C. tnindanus. 776 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON VOLUME 95, NUMB Table 2.—Some Rec northern Caribbean; (S ian Province; (G) = re Receni (N) Astraea american (S) Astraea tecta (Lii (N) Murex rubidum F (S) Murex messorius (N) Latirus cariniferu. (5) Latirus bernadem (N) Oliva reticularis (S) Oliva oblonga M (N) Olive/la mutica ( (S) Olivella petiolita (N) Enaeta cyllenifor (S) Enaeta guildingi (N) Persicula.fluctua (S) Persicula intern' (N) Prunum carneu (S) Prunum prumon (N) ('onus jaspideus (S) Conus puncticul Fig. I. Map of the Recent Caribbean Sea showing the approximate position of the line of abrupt (N) Corms spurius a faunal shift that separates the Caribbean Province into northern and southern components. (S) ('onus lorenzian Ancestromas compil Olsson and Harbiso common ancestor. Furthermore, many of these separate ancestral forms appear to have been members of their own species pairs in the Pliocene, indicating that the common ancestor for all must date from an earlier time. I will here refer to taking into acco these ancestral interprovincial sibling species pairs, which were also mutually between paleop exclusive in their ranges, as "ancestromas." Some of the Caribbean ancestromas schematically in and their living descendant pairs are listed in Table 2. The key to interpreting paraprovincialism, therefore, lies in detecting ancestromas in the fossil record. For each Caribbean ancestroma that was examined, one member was found Many of the to have been restricted to the Gatunian Molluscan Province and one to the Ca- 0. oblonga and loosahatchian Molluscan Province (Petuch 1982) (Fig. 2). The Gatunian species now can be see gave rise to the Recent southern Caribbean descendant while the Recent northern these two pairs Caribbean member of the pair arose from the Caloosahatchian member of the Con us waccam ancestroma. The Gatunian and Caloosahatchian Provinces, together, gave rise to related species, the modern Caribbean fauna (Petuch 1982) and it is important to note that their ancestral specie boundaries also ran somewhere along what is now the Nicaragua coastline and tropod pairs, o the Lesser Antilles. the Caribbean r Paraprovincialism in the Caribbean, then, appears to represent ghosts of pre- inferences