Evidence for Polyphyly of the Genus Scrupocellaria (Bryozoa: Candidae) Based on a Phylogenetic Analysis of Morphological Characters

The bryozoan genus Scrupocellaria comprises about 80 species in the family Candidae. We propose a hypothesis for the phylogenetic relationships among species assigned to Scrupocellaria to serve as framework for a phylogenetic classification using 35 morphological characters. Our results suggest that the genus Scrupocellaria is polyphyletic. Scrupocellaria s. str. is redefined according to four morphological features: vibracular chamber with a curved setal groove, ooecium with a single ectooecial fenestra, two axillary vibracula, and a membranous operculum with a distinct distal rim. Thus, the genus includes only 11 species: Scrupocellaria aegeensis, Scrupocellaria delilii, Scrupocellaria harmeri, Scrupocellaria incurvata, Scrupocellaria inermis, Scrupocellaria intermedia, Scrupocellaria jullieni, Scrupocellaria minuta, Scrupocellaria puelcha, Scrupocellaria scrupea, and Scrupocellaria scruposa. The monophyly of Cradoscrupocellaria is supported and five new genera are erected: Aquiloniella n. gen., Aspiscellaria n. gen., Paralicornia n. gen., Pomocellaria n. gen. and Scrupocaberea n. gen. Two other new genera, Bathycellaria n. gen. and Sinocellaria n. gen., are erected to accommodate two poorly known species, Scrupocellaria profundis Osburn and Scrupocellaria uniseriata Liu, respectively. Scrupocellaria congesta is tentatively assigned to Tricellaria. Fifteen species are reassigned to Licornia: Licornia cookie n. comb., Licornia micheli n. comb., Licornia milneri n. comb., Licornia curvata n. comb., Licornia diegensis n. comb., Licornia drachi n. comb., Licornia mexicana n. comb., Licornia pugnax n. comb., Licornia raigadensis n. comb., Licornia regularis n. comb., Licornia resseri n. comb., Licornia securifera n. comb., Licornia spinigera n. comb., Licornia tridentata n. comb., and Licornia wasinensis n. comb. Notoplites americanus n. name is proposed as a replacement name for Scrupocellaria clausa Canu & Bassler. Three fossil species are reassigned to Canda: Canda rathbuni n. comb., Canda triangulata n. comb. and Canda williardi n. comb. A species is reassigned to Notoplites, Notoplites elegantissima n. comb. The generic assignment of eleven species of Scrupocellaria, including Scrupocellaria macandrei, remains uncertain.

Neither a morphological nor a molecular phylogenetic hypothesis has been published for any taxa of the family Candidae, despite the molecular evidence for non-monophyletic status of Scrupocellaria [29], [30]. Thus, the goals of this study were (i) to assess and provide data on the comparative morphology of Scrupocellaria sensu lato, finding previously unrecognized homologies of the character states in order to (ii) propose a hypothesis of the phylogenetic relationships among Scrupocellaria to (iii) serve as framework for a phylogenetic classification of the group and the validation of new nomenclatural decisions.

Nomenclatural Acts
The electronic edition of this article conforms to the requirements of the amended International Code of Zoological Nomenclature, and hence the new names contained herein are available under that Code from the electronic edition of this article. This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix ''http://zoobank.org/''. The LSID for this publication is: urn:lsid:zoobank.org:pub:8A2439E2-4B08-419C-BDA2-804A675F8B7B. The electronic edition of this work was published in a journal with an ISSN, and has been archived and is available from the following digital repositories: PubMed Central and LOCKSS.

Specimens examined
For morphologic phylogenetic analysis 85 species of Candidae were included (Text S1). To prevent incompleteness of data and mislead of the characters/character states in the matrix, we did not include in the phylogenetic analysis: fossil species, species with bad preserved type material, and poorly known species whose type specimens have not been found or examined using scanning electron microscopy. In the absence of any previous phylogenetic hypothesis related to the family Candidae, we selected 8 species from four genera to serve as outgroups for the analysis, viz. Notoplites Harmer, 1923, Tricellaria Fleming, 1828, Canda Lamouroux, 1816 and Caberea Lamouroux, 1816. Incorporating these taxa was also important in order to test the monophyly of Scrupocellaria. We chose Notoplites marsupiatus (Jullien, 1882) to root the unrooted cladogram of the analysis because of its distinct scutum shape (when compared with other Candidae species) and the presence of abfrontal avicularia rather than abfrontal vibracula (a vibracular chamber is considered to be a defining characteristic of Scrupocellaria species [5], [11], [26], [31]). VMNH, Virginia Museum of Natural History (USA) All necessary permits were obtained for the described field studies in Brazil (collecting permit numbers 10186 and 19936 SISBIO/Instituto Chico Mendes de Conservação da Biodiversidade). The reported localities do not include protected areas and did not involve endangered or protected species. Permissions from all museums were obtained to access and study their collections.

Morphology and phylogenetic analysis
All specimens were examined under the stereomicroscope. Selected specimens were mounted for examination in a scanning electron microscope (SEM) (Zeiss EVO-60, Zeiss LEO 1455-VP and Zeiss DSM 940) for description and selection of the characters. We scored 35 characters for all terminal taxa; some of these characters show homoplasies among the family members (e.g. absence of scutum and rhizoids with hooks). All characters were treated as unordered and equally weighted. Autapomorphies of terminal taxa, which do not provide evidence to support monophyly at supraspecific levels, were excluded from the analysis. Unknown states were indicated as ''?'' in the data matrix, inapplicable states were indicated as (''-''). Whenever necessary, polymorphisms were explicitly considered in the coding and are marked in the data matrix. The list and discussion of characters used are given below.
The character matrix (Table S1) was edited using Mesquite v2.75 [32]. Maximum parsimony analyses were carried out using TNT v1.1 [33], adopting ''New Technology'' search algorithms (sectorial search, ratchet, tree drifting, and tree fusion) for 3,000 random addition sequences, 10 random number seeds, opting for collapsing trees after the search. The resulting forest of trees was summarized in a semi-strict consensus [34] topology. Bremer support [35] was calculated using the script Bremer.run in TNT, with configuration ''search for trees 10 times longer'', ''do 10 ratchet iterations in constrained searches'', and other settings following the standard script. The length (L), consistency index (CI) and retention index (RI) for both tree and characters were calculated in TNT. Morphological characters were optimized in the semi-strict consensus tree, and the list of state optimizations was included in supporting information Text S2.

List of characters used for phylogenetic analysis
Rhizoids ( Figures 1A-F).

4.
Position of the joints at bifurcation (L = 2; CI = 0.500; RI = 0.667): (0) passing across zooids FD and GC ( Figure 2B), (1) passing across zooids FJ and GK (Figure 2A). Remarks. Chitinous joints between branches are often reported in Candidae species, maybe as a result of branch fragmentation [26]. The feature is conspicuous in some genera (Licornia, Tricellaria, Notoplites, and in most species of Candidae). In Canda spp., the joints are often seen in older branches; and in a few Licornia species (viz., Licornia curvata, Licornia diegensis, Licornia drachi, Licornia regularis, and Licornia securifera) the joints are inconspicuous due to heavier calcification in all parts of the colonies of those species. The bifurcation pattern of the colony and position of the joints have been adopted to differentiate some genera of branching, erect bryozoans with membranous frontal walls [25], [38], [39]. The notation system used here for the ordering of the zooecia at a branching event is based on the bifurcation of biserial colonies (Figures 2A,B): ''A'' and ''B'', for the two most proximal zooids which form the bifurcation; ''C'' and ''D'', those placed on the outer sides of the branches right before the bifurcation, budding off from ''A'' and ''B'' respectively; ''E'', the axillary zooid, derived from ''A'' and lying on the inner side of ''C''; ''F'' and ''G'', on the inner side of the branches right after the bifurcation and adjacent to zooids ''D'' and ''C'' respectively; ''J'' and ''K'', the zooids derived from ''D'' and ''C'', respectively [25]. This character is not known for Aspiscellaria bellula because of the absence of bifurcations in the colonies studied; the joints are apparently rare, present in a single zooid at the base of the colony [40].   7. Adjacent zooids along the axis (L = 1; CI = 1.000; RI = 1.000): (0) placed side by side in the same plane or slightly inclined in relation to the axis ( Figures 3B,C), (1) are abruptly inclined, about 250 degrees or more in relation to the axis ( Figure 3A). Remarks. Licornia diadema, Cradoscrupocellaria bertholletii, Cradoscrupocellaria macrorhyncha, and Cradoscrupocellaria reptans have the frontal surface of adjacent zooids slightly inclined in relation to the axis in apical region of the colony, but placed side by side at the same plane in some branches at the basal region (coded with ''0'').
Zooid morphology ( Figures 3B-F). Remarks. In Scrupocaberea ornithorhynchus, the truncate distal area is reduced and shorter than those of Scrupocaberea dongolensis, Scrupocaberea gilbertensis, and Scrupocaberea maderensis. 9. Distal edge of autozooid (L = 2; CI = 1.000; RI = 1.000): (0) smooth ( Figure 3D), (1) toothed only in ovicelled zooids ( Figure 3E), (2) toothed in ovicelled and non-ovicelled zooids ( Figure 3F). Remarks. A toothed distal edge in autozooids has not yet been described for Candidae species, because it can only be observed using scanning electron microscopy. The character is considered unknown ('?') for Scrupocellaria harmeri, whose type is embedded in a Canada balsam preparation. 10. Morphology of operculum (L = 3; CI = 0.333; RI = 0.714): (0) membranous and only rim distinctly chitinous ( Figure 3B), (1) operculum wholly chitinous ( Figure 3C). Remarks. The majority of Candidae species has a membranous operculum continuous with the frontal membrane, but distinguished from it by its inverted-U-shaped and slightly chitinous distal edge. The thick and entirely chitinous opercula of Notoplites spp., Scrupocaberea dongolensis, Scrupocaberea gilbertensis, Scrupocaberea maderensis, and Scrupocaberea ornithorhynchus are placed in the obliquely truncate distal area. 11. Cryptocyst (L = 12; CI = 0.077; RI = 0.368): (0) vestigial, as a very tiny rim around the opesia ( Figure 3B), (1) forming a conspicuous stripe around the opesia ( Figure 3C). Figures 1F, 4A-H).. In Candidae the oral spine is characterized by the presence of a jointed base (sometimes with external calcification and distinct from the distal zooecial projections found in Bugula species [41]). Candidae species have a variable number of oral spines (0-7 distal spines), some of those may be distinguished by their position at the distal margin of the opesia, viz. inner, outer and median spines. Both the presence of polymorphic data and the lack of topographic correspondence suggest that not all spines are homologous, but may be a product of serial homology. Hence, it is only possible to homologize the states between the spines of the same nature, as indicated by topographical correspondence. For example, the most proximal outer spines of different taxa are comparable with each other but not with the proximal inner spines of different taxa or even those in the same individual. Thus, we coded them as three separate characters (Characters 12 and 13 and 14), i.e. proximal-most outer, the proximal-most inner and distal-most oral spines.   Figure 4H), (4) forming a single ovoid plate, but with internal channels (visible under light microscope because of their transparency) ( Figure 4C), (5) forming an asymmetrical plate, without internal channels. Remarks. Licornia diadema has variable shape of scuta, varying from a simple paddleshaped scutum to an incipient branched scutum bearing one or more slits at the outer margin (coded with ''4''). 17. Shape of scutum arising at the distal third of opesia (L = 5; CI = 0.800; RI = 0.800): (0) slender base, i.e. as wide as distal spines, with unbranched asymmetrical enlarged portion in which the distal region is less developed than the proximal one (Figures 4I-J), (1) slender base, i.e. as wide as distal spines, with an irregularly branched enlarged portion, (2) stout base, i.e. two or more times wider than distal spines, enlarged portion developed proximally ( Figure 4K), (3) stout base, i.e. two or more times wider than distal spines, enlarged portion more developed distally than proximally ( Figure 4L), (4) stout base, i.e. two or more times wider than distal spines, enlarged portion continuous with edge of opesia and with some slits at the outer margin ( Figure 1F Figure 6C). Remarks. The single fenestra is reduced to a minute drop-shaped pore in Scrupocellaria scruposa ( Figure 6A) and one minute pore in Scrupocellaria aegeensis. Smooth ooecia were described for Scrupocellaria delilii [42], but an uncalcified proximal area, like those of Tricellaria arctica, is often seen in the proximal border of the ectooecium (L.M. Vieira, unpubl. data; coded with ''0'').   Figure 7B). Remarks. Some Candidae species have abfrontal avicularia, i.e. modified zooids that lack a functional polypide and with modified operculum (mandible) [43][44][45]. Two distinct types of avicularia are found on the abfrontal surface of Candidae species: adventitious avicularia, with acute mandibles and one pore in the plane of the palate; and vibracula, with toothed setiform mandibles (setae) and with a tubular orifice at the base of seta [45]. 27. Lateral rhizoidal (rootlets) chamber associated with outer zooids at the bifurcation (L = 1; CI = 1.000; RI = 1.000): (0) absent, (1) present ( Figure 7D). Remarks. The relation between the joints and holdfast rhizoids is not altered during the development of the colony [25]. Species of Tricellaria produce holdfast rhizoids on the proximal sides of the joints, while Notoplites species produce holdfast rhizoids on the distal side of the joints [25], [26]. 28. Palatal surface of setal groove in vibracular chamber (L = 4; CI = 0.500; RI = 0.933): (0) present, complete, without foramen ( Figures 7C,E), (1) present, complete, with a foramen (opesium) ( Figure 7F), (2) absent ( Figure 7I). Remarks. In some species the palatal surface is variable, entirely complete to partially incomplete, near the tubular orifice (coded with ''0''; Figure 7E).
Tricellaria. The basal part of the tree of the Candidae has a low resolution, probably because of the high number of characters coded as inapplicable in those basal taxa causing unstable relationships. Taxonomically, we decided to consider two species of the basal polytomies to be part of the genus Tricellaria Fleming, 1828, viz. Tricellaria arctica n. comb. (Menipea arctica Busk, 1855, also referred to Scrupocellaria arctica) and Tricellaria elongata n. comb.
(Cellularia scabra f. elongata Smitt, 1868, also referred to Scrupocellaria elongata), instead of creating new generic names to accommodate these species. Our decision is based on some shared characters, such as (i) absence of abfrontal vibracula/avicularia, (ii) presence of a lateral rhizoidal chamber associated with the outer zooids of the bifurcation, (iii) a scutum arising from the distal third of the inner opesial rim and (iv) joints passing across the gymnocyst of outer zooids in the zooids C and D. The species described as Scrupocellaria congesta is distinguishable from other Tricellaria in having joints passing across the opesia of outer zooids in the zooids C and D (assigned in the tree with question mark). Tricellaria is the sister group of ?Tricellaria congesta (genus incertae sedis) + Group A + Clade B.
Group A (Aquiloniella n. gen.): taxa with basal avicularium. A polytomy of four species is here considered to be part of Group A and a large Clade B (with an unambiguous synapomorphy: presence of abfrontal vibracular chamber). The unresolved polytomy would allow a monophyletic Group A to be tested in future analysis. Nomenclaturally, it is convenient to consider the species of Group A as belonging to a unique genus, described below as Aquiloniella n. gen. All species of Aquiloniella n. gen. are endemic to Arctic and sub-Arctic waters, and may be characterized by colonies with chitinous joints passing across the gymnocyst of outer zooids of the bifurcation, as do those of Tricellaria, but with abfrontal avicularia. Thus, they are distinct from Tricellaria in the absence of the lateral rhizoidal chamber associated with the outer zooids of the bifurcation, in the presence of abfrontal avicularia, and a scutum arising at the median region of the inner part of the opesia.
Clade B: taxa with abfrontal vibracula. The analysis supports the monophyly of the species of Candidae with an abfrontal vibracular chamber (Clade B). The switch from smooth lateral edge to serrated lateral edge of the rostrum of the lateral avicularium is another synapomorphy for this clade. This clade comprises four monophyletic groups (Clade C + Clade D + Clade E + Clade F). The topology of Clade B shows an interesting history concerning the development of setal groove of the vibracular chamber along the evolution of the species of Candidae. The possession of a vibracular chamber with transversal setal groove would be primitive (plesiomorphic), as it is present in three of the included clades (Clade C, Clade D, and Clade E), and the change to an oblique setal groove would be synapomorphic for Clade F.
Clade C (Pomocellaria n. gen.): the eastern Pacific clade. Clade C seems to be endemic to the Eastern Pacific. It has a basal phylogenetic position in Clade B and it is characterized by (i) an abfrontal vibracular chamber with a transversal setal groove, (ii) ooecium with a large ectooecial fenestra, and (iii) a single axial vibracula. Presence of abfrontal vibracula with a transverse setal groove is a character also present in Clade D and Clade E, but the two clades are distinguished from Clade C by the presence of an ooecium with some ectooecial pores in Clade D and E. The dimorphic lateral avicularia, characteristics of Pomocellaria californica n. comb. and Pomocellaria varians n. comb., are absent in Pomocellaria inarmata n. comb. and Pomocellaria talonis n. comb. In the Clade D (Aspiscellaria n. gen.) and Clade E (Cradoscrupocellaria). Members of Clade D and Clade E have a circumtropical distribution in shallow waters. Clade D has an unambiguous synapomorphy, the outer spines are branched three or more times (cervicorn); this clade also includes species with an oval scutum with internal channels (ornamentation), whereas the branched scutum with a planar frontal surface, present in Aspiscellaria bellula n. comb. and in Cradoscrupocellaria, may be considered a homoplasy.
The monophyly of the genus Cradoscrupocellaria is supported here (Clade E). This genus is characterized by the presence of (i) articulate distal unbranched spines, (ii) a branched scutum arising from midline of the inner edge of the opesia, (iii) a trapezoidal vibracular chamber, (iv) single axial vibraculum, and (v) an ooecium with some ectooecial pores [24]. Character 16 (the shape of the scutum arising at the median region of opesia) is plesiomorphic for character state 1, found in majority of species, Clade F: taxa with a vibracular chamber with oblique setal groove. Clade F has an unambiguous synapomorphy, a vibracular chamber with an oblique setal groove, derived from a primitive condition of a vibracular chamber with transversal setal groove which becomes a short to long oblique setal groove. Group G (Paralicornia n. gen.). The basal part of the Clade F has a polytomy including one monophyletic clade (Paralicornia hamata n. comb. + Paralicornia obtecta n. comb. + Paralicornia sinuosa n. comb.) defined by a dimorphic lateral avicularium with trifoliate rostrum, and two other species, Paralicornia limatula n. comb. and Paralicornia pusilla n. comb. The phylogeny suggests that the polytomy may comprise a distinct clade with circumtropical distribution (Group G, named Paralicornia n. gen.) due to the (i) absence of bifurcated oral spines (characteristic of Licornia species), (ii) the presence of joints passing across the gymnocysts of outer zooids at the branch, and (iii) the presence of a shorter setal grove than those of Licornia species.
Licornia: a paraphyletic group. The monophyly of Licornia is not supported by the analysis and the position of some Licornia species remains unresolved, most likely because of the elevated number of polymorphic characters included in the data matrix. At the same time, the diagnostic characteristics of the genus described by Vieira et al. [23] are insufficient to distinguish species of Licornia from six species previously assigned to Scrupocellaria. Thus, we herein transfer these taxa to the genus Licornia: Licornia curvata (Harmer, 1926) n. comb., Licornia diegensis (Robertson, 1905) n. comb., Licornia drachi (Marcus, 1955) n. comb., Licornia regularis (Osburn, 1940) n. comb., Licornia securifera (Busk, 1884) n. comb., and Licornia tridentata (Waters, 1918) n. comb. (despite the differences in the length of setal grooves, which are longer than those of Licornia, and the presence of barely chitinized setae in Licornia). According to the phylogeny, the taxonomic position of Licornia macropora remains uncertain.
Clade H: polytomy of taxa including Scrupocellaria s. str. Despite the low resolution of the semi-strict tree, we use a part of the polytomous taxa of Clade H-characterized by presence of an avicularium at the outer wall of the ooecium-to redefine the genus Scrupocellaria s. str. according to four morphological features: (i) vibracular chamber with curved setal groove, (ii) ooecium with a single and small ectooecial fenestra, (iii) two axillary vibracula, and (iv) a membranous operculum with a distinct distal rim. Thus, the genus Scrupocellaria encompasses only nine species from the polytomy: Scrupocellaria harmeri, Scrupocellaria minuta, Scrupocellaria delilii, Scrupocellaria incurvata, Scrupocellaria inermis, Scrupocellaria intermedia, Scrupocellaria scrupea, Scrupocellaria scruposa, and Scrupocellaria aegeensis. Although these species do not form a unique group, future studies may test the monophyly of the genus.
Clade I (Scrupocaberea n. gen.). The monophyletic Clade I, here described as Scrupocaberea n. gen., comprises four species distinct from Scrupocellaria s. str. in having a (i) well chitinized operculum placed in an obliquely truncate distal area, and a (ii) scutum with a stout base arising at the distal third of opesia and with an enlarged portion developed proximally. Hence, Scrupocaberea has a mixture of the morphological features of Caberea (viz. scutum with stout base and enlarged portion developed proximally, arising from the distal third of the inner opesial rim; distinct opercular area with strongly chitinous operculum) and Scrupocellaria (viz. vibracular chamber with obliquely curved setal groove). Caberea, however, has been morphologically well defined due to the well-developed vibracular chamber with a very long setal groove and barbate seta [26], [31], [46] and, in the present phylogeny, the monophyly of the genus Caberea is supported by these two unambiguous synapomorphies. The genus Canda, previously characterized by the presence of rhizoids forming cross connections between branches and zooids in two series with their frontal surfaces facing obliquely outwards from the axis [46], has its monophyly supported by three unambiguous synapomorphies, viz. (i) joints passing across opesiae of the zooids J and K at the bifurcation, (ii) adjacent zooids abruptly inclined in relation to the axis, (iii) scutum arising at the median region of opesia and forming an asymmetrical plate, without internal channels. Diagnosis. Candidae with jointed branches, almost rectangular zooids, tapering proximally and with broadly oval opesia occupying most of the frontal surface. Joints crossing or slightly below the opesia of outer zooids and crossing the gymnocyst of the inner zooids at the bifurcation. Cryptocyst present or reduced. Oral spines often present, unbranched. Frontal scutum sometimes present, asymmetrical, arising from distal third of the inner margin of the opesia or slightly below it. Lateral avicularia present, aquiline, with a serrated rostrum and hooked tip. Frontal avicularia often present, small, monomorphic. Vibracular chamber almost triangular, with a rhizoidal foramen; setal groove curved and directed obliquely; 2 axillary vibracula. Ooecium with single ectooecial fenestra and a small avicularium at its outer border ( Figures 9A-C).
Five new genera are erected to accommodate species included in the present phylogeny: Aquiloniella n. gen., Aspiscellaria n. gen., Paralicornia n. gen., Pomocellaria n. gen. and Scrupocaberea n. gen. (see below). Two other new genera, Bathycellaria n. gen. and Sinocellaria n. gen. are erected to accommodate two additional species (specimens have not been examined using SEM; thus, they were not included in phylogeny; see Remarks on other species previously assigned to Scrupocellaria). The diagnosis of Licornia [23] is emended to include species with uncurved setal groove directed obliquely to the axis of the internode and extending twothirds or more of the vibracular chamber length; thus, in addition to the six species included in the phylogenetic analysis (Figure 8), another eight species are reassigned to Licornia (see below).
The curved setal groove of the vibraculum of members of the genus Scrupocellaria s. str. resembles those of Canda and Scrupocaberea n. gen.; the genus Canda is distinct in the shape of the internodes, position of the joints in relation to the bifurcation, the presence of interconnective rhizoids, and a well-developed cryptocyst. The genus Scrupocaberea n. gen. is distinguishable from Scrupocellaria s. str. by the presence of a well-chitinized operculum placed at the distal truncate area of the zooid (see below).
Scrupocellaria inermis is distinguishable from the other species of the genus by the absence of oral spines and scutum. The scutum is also absent in the type of the genus, Sl. scruposa. Scrupocellaria aegeensis, described from Mediterranean, has a scutum with a convex distal edge and cuspidate projections at the proximal and distal inner rim. Scrupocellaria minuta has a distinctly different scutum with a stout base three times wider than the distal spines and an enlarged portion more developed distally than proximally. Small differences are seen in scuta shape of Sl. delilii, Sl. harmeri and Sl. scrupea; they can be clearly distinguished by the position of the joints across the bifurcation, and the shape and size of abfrontal vibracula. Scrupocellaria intermedia and Sl. jullieni are distinct among Scrupocellaria species in having a scutum arising from the median region of the inner part of the opesia; Scrupocellaria intermedia is also distinct in having dimorphic lateral avicularia with trifoliate rostra. Other species with trifoliate lateral avicularia are assigned to Paralicornia n. gen. (see below). Scrupocellaria incurvata has a large scutum, as wide as the opesia; this species is also characterized by the presence of dimorphic lateral avicularia with a triangular, laterally directed mandible.
Diagnosis. Candidae with jointed branches and almost rectangular zooids, with oval opesia occupying about half of the length of the zooid. Joints crossing the gymnocyst of outer and inner zooids at the bifurcation. Cryptocyst reduced around opesia. Oral spines often present, unbranched. Frontal scuta symmetrical, oval, arising at the median region of the inner part of the opesia.
Etymology. The genus name refers to the Roman god of the north wind, Aquilon, bringer of cold winter air, in allusion to its occurrence in Arctic and sub-Arctic waters, with the Latin diminutive suffix -iella (feminine), little, in allusion to its short distal spines.
Aquiloniella n. gen. is distinguished from Tricellaria by absence of the lateral rhizoidal chamber associated to the outer zooids of the bifurcation, presence of abfrontal avicularia and a scutum arising at the median region of the inner part of the opesia. Aquiloniella n. gen. is easily set apart from Scrupocellaria s. str. in having abfrontal avicularia (rather than abfrontal vibracula in Scrupocellaria s. str.) and in the shape of lateral avicularia.
Diagnosis. Candidae with jointed branches and almost rectangular zooids, with short oval opesia occupying half-length of the zooid. Joints crossing the gymnocyst of outer and inner zooids at the bifurcation, or at proximal end of the opesia of outer zooids. Cryptocyst variably developed around opesia. Oral spines often present, with proximal-most outer spines branched two or more times (cervicorn). Frontal scuta symmetrical, oval, arising at or slightly below the median region of the inner part of the opesia.
Etymology. The genus names is formed from the word aspis (Greek), the generic term for shield, in allusion to its rounded scutum, + cellaria, used for some bryozoan genera.
Remarks. The vibracular chamber with transverse setal groove resembles those of Cradoscrupocellaria and Pomocellaria n. gen. Aspiscellaria n. gen. is easily distinguished from these two genera by its proximal-most spine which is cervicorn in shape. Pomocellaria n. gen. is distinct in the position of the scutum, arising from the distal third of the inner edge of the opesia, and in having an ooecium with a single frontal fenestra.
Three species of Aspiscellaria n. gen. are characterized by the absence of a lateral avicularium: Ap. frondis, Ap. hildae, and Ap. unicornis; these three species are distinguished from each other by the shape of the scutum, the shape and size of the frontal avicularium and the shape of ectooecial pores. Aspicellaria frondis has a rounded scutum covering the majority of the opesia, with a narrow cryptocyst, distinct from Ap. hildae and Ap. unicornis; the two later species are distinct in the size of the zooids and in having shorter frontal avicularia than Ap. unicornis. Aspiscellaria carmabi is distinguishable from Ap. piscaderaensis by the position of joints at the outer zooids at the bifurcation, and shape of frontal avicularium. Aspiscellaria cornigera is characterized by a well-developed scutum with projections at its proximal and distal inner edge. The examination of museum specimens of Aspiscellaria also revealed that additional new species await description.
Diagnosis. Candidae with jointed branches and almost rectangular zooids with short oval opesia occupying half the zooid length. Joints crossing the gymnocyst of outer and inner zooids at the bifurcation. Cryptocyst reduced around opesia. Oral spines present, unbranched. Frontal scuta symmetrical to asymmetrical, oval to subrectangular, arising at the median region (or slightly below) the inner part of the opesia. Lateral avicularia present, with a slightly serrated rostrum and straight tip; lateral avicularium sometimes replaced by an avicularium. Frontal avicularia often present, small, monomorphic. Vibracular chamber almost triangular, with a rhizoidal foramen; setal groove straight, obliquely directed and occupying half of the length of the vibracular chamber; the setal groove is placed distally to the rhizoidal pore; 1 axillary vibraculum with lateral setal groove. Ooecium with some ectooecial pores.
Etymology. The generic name refers to the similarities of this genus with some Licornia species.
Remarks. Vieira et al. [23], [24] use two major character differences, viz. presence of ooecia with ectooecial pores and single axillary vibraculum, to reassign some species of Scrupocellaria to two separate genera, Licornia and Cradoscrupocellaria. The genus Cradoscrupocellaria is quite distinct from Licornia and Paralicornia n. gen. in having a vibracular chamber with a transversal setal groove; Cradoscrupocellaria seems to be morphologically related to Aspiscellaria, but the two are distinct in the shape of the frontal scutum (branched in Cradoscrupocellaria and rounded in Aspiscellaria, excepted by Ap. belulla), the presence of dimorphic frontal avicularia (characteristic of some Cradoscrupocellaria) and the presence of branched distal spines (characteristic of Aspiscellaria). The genus Licornia resembles Paralicornia n. gen. in the direction of the setal groove of the vibraculum, but the two genera are distinct in the position of the joints in the outer zooids at the bifurcation (crossing the opesia in Licornia and the gymnocyst in Paralicornia n. gen.), the presence of shorter opesia in Paralicornia n. gen. than in Licornia, the presence of bifurcated distal spines in Licornia, and the length of setal groove, longer in Licornia species than those of Paralicornia. The gigantic trifoliate lateral avicularia found in the three known species of Paralicornia n. gen. seem to be absent in Licornia.
The examination of specimens deposited at the NHMUK, AMNH and USNM revealed that about a dozen new species of Paralicornia will also need to be described (see Figures 13G-L). Scrupocellaria spatulata (d'Orbigny, 1851) [2] has been treated as morphologically related to Pa. sinuosa [11], but due to the absence of type material and the presence of similar species, this taxon is here considered a species inquirenda, i.e. a species with doubtful identity needing further assessment.
Genus  Figures 14A-B). Diagnosis. Candidae with jointed branches and almost rectangular zooids, with oval opesia occupying half-length of the zooid. Joints crossing the gymnocyst of outer and inner zooids at the bifurcation. Cryptocyst reduced around opesia. Oral spines often present, unbranched. Frontal scuta arising at the distal third of the inner part of the opesia. Lateral avicularia often present, dimorphic. Frontal avicularia often present, small, monomorphic. Vibracular chamber trapezoidal, with a rhizoidal foramen; setal groove straight, directed transversely, placed distally to the rhizoidal pore; an axillary vibraculum with lateral setal groove. Ooecium with single ectooecial fenestra.
Etymology. The generic name is composed from pomo (an indigenous people of California) + cellaria, used for some bryozoan genera.
Remarks. Pomocellaria n. gen. is erected to include four Eastern Pacific species: Po. californica (Trask, 1857) n. comb. [76] ( Figures 14A-B (Figures 14C-D), Po. talonis (Osburn, 1950) n. comb. [12] ( Figures 14E-F), and Po. varians (Hincks, 1882) n. comb. [77] ( Figures 14G-H). Pomocellaria n. gen. is distinguishable from the other two genera with a trapezoidal vibracular chamber-i.e. Cradoscrupocellaria and Aspiscellaria n. gen.-in the position of the scutum, arising from the distal third of the inner edge of the opesia rather than the median part of the inner edge of the opesia; and in having an ooecium with a single frontal fenestra rather than one with many pseudopores. The dimorphic lateral avicularium and distal spines are absent in Pomocellaria inarmata.
Diagnosis. Candidae with jointed branches, almost rectangular zooids, broadly oval opesia occupying most of the frontal surface, and a truncate distal opercular area. Operculum wellchitinized. Joints crossing the gymnocyst of outer and inner zooids at the bifurcation. Cryptocyst present, well developed around the opesia. Oral spines present, unbranched. Frontal scuta asymmetrical, with a stout base, more developed proximally than distally, arising from the distal third of the inner margin of the opesia, below the most proximal inner spine. Lateral avicularia present, aquiline, with a serrated rostrum and hooked tip. Frontal avicularia often present, small, monomorphic. Vibracular chamber almost triangular, with a rhizoidal foramen; setal groove curved and directed obliquely; 2 axillary vibracula. Ooecium with single and large ectooecial fenestra and a small avicularium at its outer border. Distal edge of ovicelled zooid with toothed rim. Etymology. The generic name refers to the mixture of morphologic characteristics of the new genus with Scrupocellaria and Caberea species.
Scrupocaberea maderensis has been reported to be widespread in tropical and subtropical waters worldwide [6], [26], but reexamination of some of the NHMUK specimens so identified, revealed that this name represents a species complex (e.g. Figures 15H-L). At least two species were previously synonymized under Sb. maderensis by Harmer [26], viz. Scrupocaberea dongolensis and Sb. gilbertensis; these species are distinct from Sb. maderensis ( Figures 15A-C) by virtue of the number of oral spines, shape of the scutum (smaller in Sb. dongolensis and larger in Sb. gilbertensis than Sb. maderensis), shape of frontal avicularia, surface of the cryptocyst (granulose in Sb. gilbertensis), and size of the autozooids (smaller in Sb. dongolensis and Sb. gilbertensis than those of Sb. maderensis). Zooids of Sb. ornithorhynchus also have a well-chitinized operculum; this species differs from Sb. maderensis in having a vibracular chamber with a shorter setal groove and by the shape of scutum which is asymetrically developed in distal edge in Sb. ornithorhynchus rather than truncate as those of Sb. maderensis. Remarks on other species previously assigned to Scrupocellaria Four Recent species of Scrupocellaria not included in this study probably belong to Licornia due to their having porous ooecia and similarly shaped abfrontal vibracula; they are here reassigned to Licornia: Licornia mexicana (Osburn, 1950) n. comb. [12], Licornia pugnax (Osburn, 1950) n. comb. [12], Licornia spinigera (Osburn, 1950) n. comb. [12], and Licornia wasinensis (Waters, 1913) n. comb.
[39]. In L. spinigera the joints pass across proximal end of the opesia of outer zooids at the bifurcation, but pass more distally (near to the half-length of opesia) in L. mexicana and L. pugnax. Licornia wasinensis is characterized by the absence of a scutum and by dimorphic lateral avicularia with forked mandibles; this forked mandible [39] is distinguishable from the trifoliate mandible characteristic of Paralicornia species.
Three Recent species (specimens have not been examined using SEM; thus, these species were not included in the phylogeny) are unassigned to any genus of Candidae, Scrupocellaria micheli Marcus, 1955 [85] (no specimens have been found), Scrupocellaria profundis Osburn, 1950 [12] (SBMNH 96161, balsam slide, paratype; specimens have not been examined using SEM), and Scrupocellaria uniseriata Liu, 1984 [86] (no specimens have been found). The Brazilian species Scrupocellaria micheli is distinct in the irregular branching pattern of the colony and the presence of large aquiline lateral avicularia [85]. We suggest a morphological relationship between Scrupocellaria micheli and other Paralicornia n. gen. and Licornia species due to the presence of vibracula with a straight, obliquely directed setal groove occupying half of the length of the vibracular chamber, and an ooecium with some ectooecial pores; this species is tentatively assigned to Licornia, thus Licornia micheli (Marcus, 1955) n. comb. Scrupocellaria profundis Osburn, 1950 is a deep water species (recorded from more than 1000 m deep [12]), characterized by the presence of two axial vibracula and no scutum, as Sl. scruposa; this species is distinguishable from any other members of genus (as well as other genera described above) in the shape of its zooids, which are twisted at the axis of the maternal internode, and the position of the radicles chamber, lateral rather than proximally placed in the vibracular chamber and two axial vibracula with longitudinal straight setal groove (setal groove are curved in other genera with two axial vibracula, viz. Canda, Scrupocellaria and Scrupocaberea n. gen.). Bathycellaria n. gen. (urn:lsid:zoobank.org:act:362C7211-AE4D-4430-A385-B768B2E06FE8) (from the Greek word bathys, deep, in allusion of its occurrence in deep sea, + cellaria, used for some bryozoan genera; Gender, feminine) is erected to accommodate Osburn's species [12] (type species by monotypy), thus Bathycellaria profundis (Osburn, 1950) n. comb. Scrupocellaria uniseriata Liu, 1984 has unique uniserial colonies [86], distinct from other genera of Candidae; Sinocellaria n. gen. (urn:lsid:zoobank.org:act:93013294-FD7C-40D4-8361-370CF74B631D) (from sino-, meaning from China, + cellaria, used for some bryozoan genera; Gender, feminine) is erected to accommodate Liu's (1984) species (type species by monotypy), thus Sinocellaria uniseriata (Liu, 1984)

Supporting Information
Table S1 Character matrix used in phylogenetic analysis. (XLSX) Text S1 List of specimens examined and included in the phylogenetic analysis.