Marcus M. Key

Growth and carbonate production by Adeonellopsis (Bryozoa: Cheilostomata) in Doubtful Sound, New Zealand

The erect arborescent bryozoan Adeonellopsis sp. is an important component of the attached fauna on rock faces in Doubtful Sound, New Zealand. A program of marking and harvesting, radiocarbon dating, and morphometric study was undertaken to determine age, growth rate, and carbonate production rate of these colonies. Data from 40 branches on each of five colonies show a growth rate of 6.9 mm/yr in branch length. Colony growth rate varied, with 71% of growth (5 mm per branch) occurring from mid-summer and to mid-winter, and 29% (2 mm per branch) from midwinter to late summer. Since proximal secondary thickening is common in adeoniform species, and occurs in Adeonellopsis, additional carbonate may be precipitated annually by this means. The largest colonies found in Doubtful Sound, some up to 30 cm in diameter, may be as much as 20 yr old, and precipitate calcium carbonate at a rate of 24 g CaCO3/yr. At Bauza Island, where our study was carried out, population densities of one large colony/m produced carbonate at a rate of 24 g CaCO3/m 2 /yr; maximum theoretical density could produce carbonate at 1042 g CaCO3/m 2 / yr. Carbonate produced at these rates would accumulate in sediments at 4^174 cm/kyr, reasonable rates for temperate carbonates. Adeonellopsis provides substrate for epizoa and hiding places for motile organisms. They form a potentially important fiord microhabitat, and their longevity allows both more ephemeral organisms and young longer-lived colonies to grow under their protection. fl 2001 Elsevier Science B.V. All rights reserved.

Bryozoan colonization of the marine isopod Glyptonotus antarcticus at Signy Island, Antarctica

Abstract Sixty specimens of the giant marine isopod Glyptonotus antarcticus Eights, collected from Borge Bay, Signy Island, Antarctica were examined for epizoans. Ten species of cheilostomatid bryozoans were found on the isopods. The purpose of the study was to quantify the prevalence, intensity, abundance, and spatial distribution of the bryozoans on the isopods. The proportion of isopods colonized was 42%. The larger isopods had both significantly more epizoic bryozoan colonies and species. The greatest density of bryozoans was on the fused pleon and telson. There was no significant difference between the dorsal and ventral abundance of bryozoan colonies. The diversity of epizoic bryozoans on the isopods is higher than on other host organisms from more stable environments. This may be because of active selection by settling larvae. The frequency of local substrata being scoured by ice is high around Signy Island, so there may be a selective advantage in colonizing a motile host.

Upper Ordovician Bryozoa from the Montagne de Noire, Southern France

Synopsis This study focuses on bryozoans from the Upper Ordovician rocks of the Montagne de Noire, southern France and additional material from contemporary rocks of the Carnic Alps. Based on museum collections, 68 bryozoan species were identified with 18 species being new: Ceramo‐porella grandis sp. nov., Crassalina fungiforme sp. nov., Lichenalia nodata sp. nov., Atactoporella magnopora sp. nov., Dekayia buttleri sp. nov., Stigmatella carnica sp. nov., Trematopora gracile sp. nov., Bythopora tenuis sp. nov., Nicholsonella divulgata sp. nov., N. recta sp. nov., Matsutrypa elegantula sp. nov., M. rogeri sp. nov., Nematotrypa punctata sp. nov., Stellatodictya valentinae sp. nov., Ptilodictya feisti sp. nov., Pseudohornera dmitrii sp. nov., Ralfinella elegantula sp. nov. and Moorephylloporina contii sp. nov. Trepostomes are the most abundant and diverse group with 40 of the total 68 species, but cyclostomes, cystoporates and cryptostomes are also present. The age of the fauna is Caradoc to Ashgill, according to the distribution of species and genera. The fauna has palaeogeographical connections to the Upper Ordovician of Wales, Estonia and North America.

A new family of trepostome bryozoans from the Ordovician Simpson Group of Oklahoma

A new family, Bimuroporidae, is proposed for a clade of Ordovician trepostome bryozoans. The family is united by several characteristics, including a zooidal ontogenetic progression from mesozooid to autozooid and an integrate wall structure. Discriminant and cladistic analyses of colonies from the Ordovician Simpson Group outcropping in the Arbuckle Mountains and Criner Hills of south-central Oklahoma permit the recognition of eight species belonging to this family. Four species assigned to the new genus Bimuropora are described: B. dubia (Loeblich), B. pollaphragmata n. sp., B. conferta (Coryell), and B. winchelli (Ulrich), as well as four species assigned to the genus Champlainopora Ross: C. chazyensis (Ross), C. ramusculus n. sp., C. pachymura (Loeblich), and C. arbucklensis n. sp.

The halloporid trepostome bryozoans from the Ordovician Simpson Group of Oklahoma

-The Bromide Formation of the Middle Ordovician Simpson Group of Oklahoma contains one of the oldest diverse bryozoan faunas in North America. The early divergence of many trepostome clades is revealed in these rocks. Three trepostome bryozoan species belonging to family Halloporidae are described from this fauna. Discriminant analysis is used to define the following halloporid species: Diplotrypa schindeli n. sp., Tarphophragma karklinsi n. sp., and Tarphophragma macrostoma (Loeblich). Preliminary cladistic analysis indicates that the family Halloporidae was already a distinct lineage by the Middle Ordovician. This suggests that by this time, many of the major trepostome clades were already established.

Paleoecology of Commensal Epizoans Fouling Flexicalymene (Trilobita) from the Upper Ordovician, Cincinnati Arch Region, USA

Abstract Commensal epizoozoans and episkeletozoans are rarely preserved attached to the external exoskeleton of the Late Ordovician trilobite Flexicalymene. Of nearly 15,000 Flexicalymene specimens examined, 0.1% show epizoozoans or episkeletozoans. Factors limiting Flexicalymene fouling include a shallow burrowing life style, frequent molting of the host, larval preference for other substrates, observational bias caused by overlooking small fouling organisms, and the loss of the non-calcified, outermost cuticle prior to fossilization or as the trilobite weathers from the encasing sediment. Trepostome bryozoans, articulate and inarticulate brachiopods, cornulitids, and a tube-dwelling/boring nonbiomineralized organism represent the preserved members of the Late Ordovician marine hard substrate community fouling Flexicalymene. This assemblage of organisms is less diverse than the hard substrate community fouling Late Ordovician sessile epibenthic organisms. Fouling is not restricted to only large Flexicalymene specimens as observed in previous studies but occurs in medium to large individuals interpreted as early to late holaspid specimens. Epizoozoans fouling the carcasses or molt ensembles of 16 Flexicalymene specimens provide insight into the life habits of the host and these fouling organisms. Trepostome bryozoans, articulate and inarticulate brachiopods, and cornulitids preferentially attached to elevated portions of the dorsal exoskeleton, and preferentially aligned in either the direct line or lee side of currents generated by Flexicalymene walking on the sea floor or swimming through the water column.

Stable isotope values in modern bryozoan carbonate from New Zealand and implications for paleoenvironmental interpretation

Abstract Bryozoan carbonate contains useful geochemical evidence of temperate shelf paleoenvironments. Stable isotope values were determined for 103 modern marine bryozoan skeletons representing 30 species from New Zealand. δ18O values range from‐1.4 to 2.8‰VPDB, while δ13C range from ‐4.5 to 2.8‰ VPDB (values uncorrected for mineralogical variation). These values are distinct from those of both tropical marine skeletons and New Zealand Tertiary fossils. Most bryozoans secrete carbonate in or near isotopic equilibrium with sea water, except for Celleporina and Steginoporella. The complex and variable mineralogies of the bryozoans reported here make correction for mineralogical effects problematic. Nevertheless, mainly aragonitic forms display higher isotope values, as anticipated. Both temperature and salinity constrain δ18O and δ13C values, and vary with latitude and water depth. Ten samples from a single branch of Cinctipora elegans from the Otago shelf cover a narrow range, although the striking difference in carbon isotope values between the endozone and exozone probably reflects different mineralisation histories. Our stable isotope results from three different laboratories on a single population from a single location are encouragingly consistent. Monomineralic bryozoans, when carefully chosen to avoid species suspected of vital fractionation, have considerable potential as geochemical paleoenvironmental indicators, particularly in temperate marine environments where bryozoans are dominant sediment producers.

Epizoic Bryozoans on Cephalopods Through the Phanerozoic: A Review

Abstract Spatiopora Ulrich, 1882 is a trepostome bryozoan that is found encrusting living orthoconic nautiloids in the Upper Ordovician (Katian) of North America, as do several other bryozoans. These epizoozoan bryozoans are characterized by possessing thin unilaminate zoaria with rows of elongate maculae, which may be monticulate and aligned coaxially to the host growth axis. These develop a distinctive linear shape in response to growing on a conical host, rather than as a response to channelized water flow along the host. Monticules increase in size and spacing adorally until a maximum inter-macular area is reached that results in a decline in surface water flow efficiency, and a new monticular line is inserted. Orthocones normally swam forward at lower velocities that enabled lophophore eversion and feeding, which would have been impossible at the higher speeds reached when the host jetted backwards during escape. Monticules reduced drag and turbulence acting on the orthocones which allowed for more efficient venting of bryozoan macular excurrents. Characteristic elliptical monticule growth continued even after death of the motile host. A Trypanites-bryozoan-orthoconic nautiloid association shows a complex biological and taphonomic relationship between these organisms.Cephalopods have a long geological history ranging from the Cambrian to the Recent (Holland 1987; Benton 1993; Kröger et al. 2011) and have provided substrates for many encrusting skeletobionts (see review in Taylor & Wilson 2003: 28-29) including bryozoans from their appearance in the Ordovician. Cephalopods may be fouled while alive (e.g., Landman et al. 1987; Wyse Jackson et al. in press); on specimens that were necroplanktonic—dead floating shells (Davis et al. 1999; Taylor & Monks 1997); or encrustation may have been post-mortem (e.g., Mapes et al. 2010; Rakociński 2011). The distribution of fossil episkeletozoans (sensu Taylor & Wilson 2002) on their hosts can provide details of lifestyles of the host, their feeding habits as well as those of the encrusting organism, information on taphonomic processes, and as has been postulated recently to aid in our understanding of the post-mortem disperal of shells (Reyment 2008). Settlement of bryozoan larvae on motile benthic or nektonic host substrates occurs much less frequently than on sessile epibenthic hosts or hardgrounds (Taylor 1990). Bryozoan encrustation of motile hosts in the fossil record include those on trilobites (Key et al. 2010), cephalopods (Baird et al. 1989; Wyse Jackson et al. in press), and echinoderms (Schneider 2003). Motile hosts encrusted by modern bryozoans include cephalopods (Landman et al. 1987), sea snakes (Key et al. 1995), king or horseshoe crabs (Key et al. 1996a, 1996b, 2000), decapod crabs (Key et al. 1999), hermit crabs (Balazy & Kuklinski 2013), pycnogonids (Key et al. 2012), isopods (Key & Barnes 1999), and sea turtles (Frazier et aI. 1992). Aside from bryozoans, numerous sessile organisms have encrusted cephalopods: brachiopods (Holland 1971; Gabbott 1999; Evans 2005), cornulitids (Evans 2005), crinoids/pelmatozoans (Prokop & Turek 1983; Evans 2005; Rakociński 2011; Evans et al. 2013), edrioasteroids (Baird et al. 1989), cystoids (Klug & Korn 2001), corals (Marek & Galle 1976; Baird et al. 1989), microconchids (Watkins 1981; Klug & Korn 2001; Evans 2005; Rakociński 2011), stromatoporoids (Ulrich, 1886), the hederelloid Reptaria stolonifera (Baird et al. 1989; Taylor & Wilson 2008), the problematica Vinella radialis (Ulrich 1893), and Sphenothallus, that forms black spots on the surfaces of Ordovician cephalopods from Ohio (Neal & Hannibal 2000). ISSN 2035-7699

Epizoozoan trepostome bryozoans on nautiloids from the Upper Ordovician (Katian) of the Cincinnati Arch region, U.S.A.: an assessment of growth, form, and water flow dynamics

Abstract Spatiopora Ulrich, 1882 is a trepostome bryozoan that is found encrusting living orthoconic nautiloids in the Upper Ordovician (Katian) of North America, as do several other bryozoans. These epizoozoan bryozoans are characterized by possessing thin unilaminate zoaria with rows of elongate maculae, which may be monticulate and aligned coaxially to the host growth axis. These develop a distinctive linear shape in response to growing on a conical host, rather than as a response to channelized water flow along the host. Monticules increase in size and spacing adorally until a maximum inter-macular area is reached that results in a decline in surface water flow efficiency, and a new monticular line is inserted. Orthocones normally swam forward at lower velocities that enabled lophophore eversion and feeding, which would have been impossible at the higher speeds reached when the host jetted backwards during escape. Monticules reduced drag and turbulence acting on the orthocones which allowed for more efficient venting of bryozoan macular excurrents. Characteristic elliptical monticule growth continued even after death of the motile host. A Trypanites-bryozoan-orthoconic nautiloid association shows a complex biological and taphonomic relationship between these organisms.Cephalopods have a long geological history ranging from the Cambrian to the Recent (Holland 1987; Benton 1993; Kröger et al. 2011) and have provided substrates for many encrusting skeletobionts (see review in Taylor & Wilson 2003: 28-29) including bryozoans from their appearance in the Ordovician. Cephalopods may be fouled while alive (e.g., Landman et al. 1987; Wyse Jackson et al. in press); on specimens that were necroplanktonic—dead floating shells (Davis et al. 1999; Taylor & Monks 1997); or encrustation may have been post-mortem (e.g., Mapes et al. 2010; Rakociński 2011). The distribution of fossil episkeletozoans (sensu Taylor & Wilson 2002) on their hosts can provide details of lifestyles of the host, their feeding habits as well as those of the encrusting organism, information on taphonomic processes, and as has been postulated recently to aid in our understanding of the post-mortem disperal of shells (Reyment 2008). Settlement of bryozoan larvae on motile benthic or nektonic host substrates occurs much less frequently than on sessile epibenthic hosts or hardgrounds (Taylor 1990). Bryozoan encrustation of motile hosts in the fossil record include those on trilobites (Key et al. 2010), cephalopods (Baird et al. 1989; Wyse Jackson et al. in press), and echinoderms (Schneider 2003). Motile hosts encrusted by modern bryozoans include cephalopods (Landman et al. 1987), sea snakes (Key et al. 1995), king or horseshoe crabs (Key et al. 1996a, 1996b, 2000), decapod crabs (Key et al. 1999), hermit crabs (Balazy & Kuklinski 2013), pycnogonids (Key et al. 2012), isopods (Key & Barnes 1999), and sea turtles (Frazier et aI. 1992). Aside from bryozoans, numerous sessile organisms have encrusted cephalopods: brachiopods (Holland 1971; Gabbott 1999; Evans 2005), cornulitids (Evans 2005), crinoids/pelmatozoans (Prokop & Turek 1983; Evans 2005; Rakociński 2011; Evans et al. 2013), edrioasteroids (Baird et al. 1989), cystoids (Klug & Korn 2001), corals (Marek & Galle 1976; Baird et al. 1989), microconchids (Watkins 1981; Klug & Korn 2001; Evans 2005; Rakociński 2011), stromatoporoids (Ulrich, 1886), the hederelloid Reptaria stolonifera (Baird et al. 1989; Taylor & Wilson 2008), the problematica Vinella radialis (Ulrich 1893), and Sphenothallus, that forms black spots on the surfaces of Ordovician cephalopods from Ohio (Neal & Hannibal 2000). ISSN 2035-7699

Epizoic Bryozoans on Predatory Pycnogonids from the South Orkney Islands, Antarctica: “If You Can’t Beat Them, Join Them”

Antarctic bryozoans are poor spatial competitors compared to many sessile invertebrates. Antarctic bryozoans are frequently destroyed by ice scouring of the substratum during open water periods, and Antarctic bryozoans are specifically preyed upon by pycnogonids. Based on this, it was hypothesized that Antarctic bryozoans should foul pycnogonids more than other motile hosts and other sessile biotic and abiotic substrata. To test these hypotheses, 115 live pycnogonids were collected in the South Orkney Islands, Antarctica. Their carapaces were examined for epizoic bryozoans, and each colony’s size was measured and its location mapped. Nine species of pycnogonids were identified containing 156 bryozoan colonies belonging to seven cheilostome species. Of the 115 pycnogonids, 26% were fouled by bryozoans. The bryozoan species richness on pycnogonids is similar to that on the adjacent boulders. Compared to other motile host animals, the number of bryozoan species per unit host surface area is an order of magnitude higher on pycnogonids. This may be attributed to carapaces of pycnogonids acting as refugia for the bryozoans from competition for space on hard substrata, ice scour, and predation by their host.