On the species of the genus Selliporella SARTONI & CRESCENTI , 1962 from the Middle Jurassic of the coastal Dinarides of Croatia

An emended diagnosis of the genus Selliporella and its type-species, S. donzellii SARTONI & CRESCENTI is proposed, based on the proven existence of non-ramified laterals in the mature (basal) part of the thallus and their ramification in its higher (juvenile) parts. Given the differences in the morphological characteristics of laterals in the upper parts of the thallus, the type-species has been split into two varieties: S. donzellii var. donzellii SARTONI & CRESCENTI and S. donzellii var. galaeformis n. comb. Selliporella cornutuformis n. sp. is proposed, characterized by a distinctly articulated (segmented) and spiky thallus, with each primary lateral bearing a bundle of several trichophorous secondaries. The generic attribution of species originally described as Diplopora johnsoni PRATURLON and Triploporella neocomiensis RADOIČIĆ has been reviewed, resulting in their being unified as the same species, which, according to its newly observed morphological characters, has been ascribed to the genus Pseudoclypeina. As Diplopora johnsoni has been validly described, Triploporella neocomiensis becomes, taxonomically, the younger synonym of Pseudoclypeina johnsoni (PRATURLON) n. comb. donzellii, given by SOKAČ & VELIĆ (1978), the presence of segments with two or three rows of whorls was explicitly mentioned for the first time, but still with an emphasis on undivided laterals of the piriferous type. However, as later emphasized by BARATTOLO et al. (1992), that addition could not be accepted due to the afore-mentioned morphological characteristics and also because the form illustrated by SOKAČ & VELIĆ (1978; pls. I-V) didn’t correspond to the type-species characteristics. A new amended diagnosis of Selliporella donzellii SARTONI & CRESCENTI was given by BARATTOLO et al. (1992, p. 604). Based on analysis of numerous sections from samples collected from a number of localities in the Apennines and Dinarides, they gave a detailed description concerning the shape and distribution (arrangement) of bipartite laterals, the thallus morphology, with both the sections illustrated (BARATTOLO et al., 1992, pls. I-IV) and with graphic interpretation (BARATTOLO et al., 1992, figs. 1-4). They summed up the characters of the species as follows: „Euspondyle dasyclad alga uniformly articulated or, instead, articulated only in some regions of the thallus. Each article is provided of primary branches arranged in a couple of secondary branches. The primaries are short, and laterally compressed, they are subrectangular in cross-section. The secondary branches are trichoporous, sturdy, and relatively long; they are proximally perpendicular to the main axis but outwards they bend gradually upwards. They grow in tufts of two on each primary branch.“ Based on these characteristics of the type-species, they also gave a summary diagnosis of the genus, and commented on Neoteutloporella gallaeformis (RADOIČIĆ), for which they stated that it „might be“ a higher, non-segmented part of the Selliporella donzellii thallus, thus being its younger synonym. As for the form ascribed to Selliporella donzellii and illustrated in SOKAČ and VELIĆ (1978, pls. I-V), they emphasized its being impossible to be identified with the type-species, but possibly belonging to the same genus (i.e., Selliporella). Article history: Manuscript received August 03, 2017 Revised manuscript accepted October 04, 2017 Available online October 31, 2017


INTRODUCTION
The genus Selliporella SARTONI & CRESCENTI, 1962 was established on the basis of inadequately illustrated, fragmented sections of individual whorls.Thus, the lack of more complete parts of thallus resulted, then, in an incomplete diagnosis as follows: "Essentially cylindrical thallus, with generally detached and separately fossilized whorls.Fertile whorls in a basket shape, each one formed by laterals of two or more superposed rows.Phloiophorous laterals are welded together.Laterals of the same row communicate with one another; but the laterals of the various rows of the same whorl have rare, sporadic and often absent communication."(SARTONI & CRESCENTI, 1962).Such inadequate and even, to some extent confusing, diagnosis resulted in donzellii, given by SOKAČ & VELIĆ (1978), the presence of segments with two or three rows of whorls was explicitly mentioned for the first time, but still with an emphasis on undivided laterals of the piriferous type.However, as later emphasized by BARAT-TOLO et al. (1992), that addition could not be accepted due to the afore-mentioned morphological characteristics and also because the form illustrated by SOKAČ & VELIĆ (1978; pls.I-V) didn't correspond to the type-species characteristics.A new amended diagnosis of Selliporella donzellii SARTONI & CRESCENTI was given by BARATTOLO et al. (1992, p. 604).Based on analysis of numerous sections from samples collected from a number of localities in the Apennines and Dinarides, they gave a detailed description concerning the shape and distribution (arrangement) of bipartite laterals, the thallus morphology, with both the sections illustrated (BARATTOLO et al., 1992, pls.I-IV) and with graphic interpretation (BARATTOLO et al., 1992, figs. 1-4).They summed up the characters of the species as follows: "Euspondyle dasyclad alga uniformly articulated or, instead, articulated only in some regions of the thallus.Each article is provided of primary branches arranged in a couple of secondary branches.The primaries are short, and laterally compressed, they are subrectangular in cross-section.The secondary branches are trichoporous, sturdy, and relatively long; they are proximally perpendicular to the main axis but outwards they bend gradually upwards.They grow in tufts of two on each primary branch."Based on these characteristics of the type-species, they also gave a summary diagnosis of the genus, and commented on Neoteutloporella gallaeformis (RADOIČIĆ), for which they stated that it "might be" a higher, non-segmented part of the Selliporella donzellii thallus, thus being its younger synonym.As for the form ascribed to Selliporella donzellii and illustrated in SOKAČ and VELIĆ (1978, pls.I-V), they emphasized its being impossible to be identified with the type-species, but possibly belonging to the same genus (i.e., Selliporella).
After extensive investigations of numerous sections in the samples from the Dinaridic coastal region, it was noticed that only a part of these sections may be reliably ascribed to Selliporella donzellii, within the frame and according to the emended diagnosis of BARATTOLO et al. (1992).Quite a large amount of sections, contained in the type-species bearing sample, showed bipartite laterals differing in morphology from what was previously described.Some sections, rather rare in the bulk of algal fragments, mixed with variously preserved sections of the type species, differ from those in being distinctly smaller, showing an articulated thallus, and having mutually separated, undivided, clearly piriferous laterals.Taken individually, with their completely different morphology of both thallus and laterals, these sections appeared unidentifiable with Selliporella donzellii and, at first glance, suggested a possibility of belonging to the genus Neoteutloporella (A similar section was illustrated by RADO I-ČIĆ, 1965, pl. IV, fig. 4, and labelled? Teutloporella).We identified these sections as representing the basal parts of the thalli of the type-species.
However, in reviewing the existing descriptions and amendments, we noticed the lack of more detailed biometric parameter values.Thus in the original description (SARTONI & CRES-CENTI, 1962) there were only three values mentioned (L, D, w) or, if we take Neoteutloporella gallaeformis as a younger synonym of Selliporella donzellii, two more can be added (l, p).The position of sections figured by SOKAČ & VELIĆ (1978, tab. I-V) and ascribed to the type-species, remain unsolved.Such open questions resulting from earlier papers, and more of the same, inspired us to undertake a revision of our own earlier determinations and opinions.
In this paper, we again analysed numerous algal-bearing samples from several localities in the central and southern Dalmatian coastal area (Mt.Biokovo, the environs of Neum, Osojnik NW of Dubrovnik, as well as the Konavle hills SE of Dubrovnik).The samples analysed and illustrated here have been collected by several researchers from the Croatian Geological Survey (former Institute of Geology) during the last 30 years or so.After the analysis of the aforementioned samples we came to the following conclusions: -Selliporella donzellii is highly variable with regard to the morphology of the thallus and laterals, depending primarily on which parts of thallus, i.e. mature or juvenile, are compared; -That the emendation of Selliporella donzellii SARTONI & CRESCENTI as given by BARATTOLO et al. (1992) is fully applicable only for juvenile (higher) parts of thallus; -That the supposition in the separately given opinion of Barattolo and De Castro in BARATTOLO et al. (1992), that Teutloporella gallaeformis RADOIČIĆ is a younger synonym of Selliporella donzellii, i.e., its juvenile (higher) thallus part, is correct.Sections with the characteristic shape and bulkiness of the secondary laterals, usually il-lustrated under the name Teutloporella gallaeformis, should be separated as a new variety of the type-species; -That the sections illustrated in SOKAČ & VELIĆ (1978, tab.I-V) under the name Selliporella donzellii SARTONI & CRESCENTI, whose assignment to that species was questioned by BARATTOLO et al. (1992), doubtlessly belong to the genus Selliporella and can be singled out as a new species, introduced here as Selliporella cornutuformis n. sp.; -That the biometric parameters of the type-species should be given separately for different parts of its thallus; -That the variability in the building elements of Selliporella donzellii is intraspecific, but individual specimens with distinctly pronounced peculiar morphologic characteristics may be separated as varieties of the same species.
Moreover, discussion of the generic attribution of the species originally described under the name Triploporella neocomiensis RADOIČIĆ, which was subsequently transferred to Selliporella is warranted (BUCUR & SĂSĂRAN, 2003).

Pls. I -IX
After studying a large number of variously oriented sections in one or several samples, a new and more complete understanding of the very variable morphology of the thallus as a whole and of changing type and shape of laterals from undivided to divided has arisen.Laterals may be present in sections cutting different parts of the thallus, depending on their growth stage.d/D 0,230-0,500 0,200-0,541 0,210-0,356 h 0,14-0,46 0,20-0,62 0,28-0,30 p 0,04-0,16 --p´-0,05-0,24 0,16-0,30 p´´-0,06-0,20 0,18-0,30 l 0,50-0,94 --l´-0,24-0,30 0,20-0,35 l´´-0,48-0,72 0,50- The calcareous thallus has a rather variable shape, depending on the distance between neighbouring whorls, the shape of undivided or divided laterals, and their inclination.Basal (= mature) part of thallus is distinctly articulated, and thus acquiring a spiny (spinose) shape, as a result of clearly separated whorls of piriferous laterals with distally individualized calcareous envelopes (Pl. I,(7)(8)(9).Going upwards, laterals became divided (Pl. I,fig. 6,Pl. IV,Pl. V,fig. 5), resulting in more massive articles, with, in some sections, visible annulation in between (Pl. IV,Pl. VI,fig. 8;Pl. VII,fig. 7;Pl. VIII,fig. 1).In other sections, annulation is unclear or absent.Each article represents one whorl.In higher (= juvenile) parts of the thallus, the distance between neighbouring whorls gradually diminishes, while the diameter of both primaries and secondaries, as well as the height of the articles, visibly increases, with reduced annulation which leads to the appearance of a seemingly non-articulated thallus.In some sections of the juvenile part of the thallus horizontal fissures are visible (Pl. VI,fig. 8,part.;Pl. VII,fig. 6,part.;Pl. VIII,figs. 6,8), which represent reduced annulation resulting from calcification of the individual whorls of ramified laterals.Vertical, oblique, or irregular, sections, observed in places (Pl. VII,bottom;Pl. VIII,fig. 9), mainly divide pairs of secondary laterals, as a result of the calcification of individual laterals.Generally, annulation is typically present in the basal part of the thallus, more or less displayed in middle parts, and reduced in the upper parts.That is a result of differences in the distance between neighbouring whorls and the shape and the inclination of the laterals, together with the presence of individual calcareous sheets (DE CASTRO, 1997) of laterals.In its basal part, the thallus is cylindrical and distinctly annulated, becomes slightly club-shaped, with reduced annulation and thus acquiring a seemingly compact shape (Pl. IV,fig. 8;Pl. V,fig. 2;Pl. VII,fig. 6).
Euspondylity is clearly visible in all parts of the thallus.As already mentioned, going from the mature to juvenile parts of the thallus, the type of laterals, their shape, and their number per whorl change.In the basal thallus parts, the laterals are piriferous simple (undivided), not distinctly pear shaped (Pl. I,(7)(8)(9)Pl. II,figs. 2,(4)(5)(7)(8)(9)Pl. IV,fig. 1 bottom).By their proximal ends, the laterals of the same whorl are mutually in close contact, thus forming an uninterrupted calcareous ring.(Pl. III,(6)(7).More distally, the laterals of the same whorl grow more wide apart and became more clearly separated, each one being enveloped in a thin individual calcareous sheath, giving the thallus a distinctly spiky (spinose) appearance.The number of laterals in a whorl at this level of the thallus increases gradually from a minimum of 6 (Pl.III, fig.7) to 10-12 (Pl. III, figs. 1-2, 6, 8-9).The laterals are directed obliquely upwards, under an angle of 20°-50°, more steeply in the upper thallus parts (Pl. I,figs. 1,(3)(4)(5)(7)(8), Also, going to higher levels, the simple (undivided) laterals pass into ramified laterals, more gently inclined to the horizontal plane (Pl. IV,fig. 1).The appearance of the first ramified laterals is characterized by variably shaped primaries, ranging from short tubular (Pl. IV,fig. 3,5,9), proximally more or less irregularly widened (Pl. IV,part fig. 5,7,fig. 8 bottom), to visibly swollen (Pl. IV,fig. 1 top,fig. 8 top).In the middle part of the thallus, the proximal ends of the primaries are, in general, well preserved, so that the central cavity is still clearly defined (Pl. IV,(9)(10)8 bottom).Articulation here can be either clearly pronounced (Pl. IV,Pl. VI,fig. 8;Pl. VII,figs. 5,7) or just indicated, but barely observable.Going upwards, the primaries became larger, of ellipsoidal, or irregularly circular shape (Pl. V,6) or, sometimes, with lowered (dropped) bases, acquiring a stocky, basket-like shape (Pl. V,fig. 2;Pl. VI,fig. 1;Pl. VII,fig. 5), as mentioned and illustrated by BARATTOLO et al. (1992, fig. 3), thus indicating the pronounced variability in the primaries' shape.In the upper parts of the thallus, the number of laterals per whorl varies from 20 to 30.The distance between neighbouring whorls decreases, leading to ever more close contact of their laterals (Pl. VI,fig. 1), sometimes to the joining of their pores in their proximal parts (Pl. V,fig. 6;Pl. VII,.In this region of the thallus, the primaries are most frequently, partly or completely, destroyed, their shape being recognizable only with difficulty, with a secondarily widened and indistinctly delineated central cavity (Pl. IV,fig. 8 top;Pl. V,part. fig. 2;Pl. IX,fig. 1).Such an appearance is caused by the laterals being pressed together and, consequently, having thinner (or non-existent) calcareous envelopes, easily prone to destruction.
Each primary lateral bears a pair of piriferous secondaries, of which the lower one is always larger, attaining up to three times a larger diameter then that for the upper lateral, and having a more distinctly piriferous shape.In tangential sections through the upper parts of the thallus, the different diameter of the secondaries belonging to the same pair, is indicated by alternately occurring large and smaller pores (Pl. VI,fig. 8;Pl. VII,Pl. VIII,fig. 8).The secondaries, though being approximately horizontal in their proximal parts, going outwards gradually bend upwards and their calcareous envelopes become separated.In the distal tangential sections, this feature gives a picture of an joint envelope of the same pair (outer parts of the skeleton being fissured), whereas in the top parts it appears as single circular pores with individual envelopes (Pl. VII,fig. 2 bottom,Pl. VIII,fig. 9;Pl. IX,fig. 2 top) and shallow spinose outer surface.Laterals of the same pair grow one above the other, but going upwards, the direction of growth of the thinner, upper lateral slightly diverges sideways, in relation to the lower, larger lateral.In tangential sections this appears as an alternating distribution of rows with larger pores, belonging to larger lower laterals, and rows of smaller pores, deriving from thinner, upper laterals of neighbouring pairs of the same whorl (Pl. VII,Pl. VIII,fig. 8;Pl. IX,fig. 2 top).Variability concerning the size and shape of the lower, larger secondary lateral is very frequent, whereas the dividing (branching) of the secondaries is anomalous and occurs only rarely (Pl. V,fig. 3 arrow).Specimens with enormously large and visually variously shaped secondaries have been singled out as the new variety.
The species is most likely cladosporous, a conclusion based on the large relative size of its laterals.This may be supported by the presence of single micritic bodies of 0.10 mm in diameter, possibly representing dispersed cysts, that have been observed in the primaries, and more frequently in the larger of the secondaries (not illustrated).
The type species is characterized by a wide range of morphology from the basal to the top part of the thallus.This is due to the type of laterals, their gradual increasing number per whorl going upwards, their variable declining angle in relation to the central axis of growth, variable distance between the neighbouring whorls, their more or less pronounced growth (becoming larger) of the primaries and secondaries, leading to variable values of outer and inner diameters.
We propose the following emended diagnosis of Selliporella donzellii SARTONI & CRESCENTI: The type species of the genus Selliporella is clearly euspondyle, cylindrical to slightly claviform shape, distinctly articulated in the lower parts and with reduced annulation in the upper parts.In the lower part, it has undivided piriferous laterals, each having a distally individualized calcareous envelope.Going upwards, the undivided laterals pass into clearly differentiated primaries and secondaries.Each primary lateral bears a pair of more or less distinctly piriferous secondaries, which diverge laterally.
In accordance with the emended species-specific diagnosis, we propose the following emended generic diagnosis of the genus Selliporella SARTONI & CRESCENTI: Cylindrical to slightly claviform, more or less segmented thallus.Laterals arranged in whorls, undivided in the lower part of the thallus, divided in the upper.Primaries of variable shape, from tubular to more or less inflated.Secondaries trichophorous to piriferous.The establishment of a new variety within Selliporella donzellii SARTONI & CRESCENTI is based on differences between individual biometrics in the upper thallus part with regard to the same parameters in the typical variety.This results in morphological variability, intensity of calcification, and, thus, the state of preservation.The lack of sections of transition from the lower to the upper part of the thallus in S. donzellii var gallaeformis may be a question, but the discovery of such a section is merely luck.For S. donzellii, along with its numerous illustrations by many authors, the transition from the lower to the upper part of the thallus has only been observed in a few sections, in the 50 years from its first description.

Selliporella donzellii
In numerous sections derived from the same sample (O-79), the new variety is represented by about 10% of the total number of sections of the various parts of the thallus of the type species.The analysed and illustrated sections (Pls.X-XII) have been ascribed to the upper parts of the typical variety, because other thallus parts, which would, by their characteristics, diverge from the above described in the typical variety of Selliporella donzellii, have not been observed.Moreover, some sections (Pl. IX, partly include features characteristic of both varieties, which, in such cases, makes their undoubted separation impossible, but clearly indicates their belonging to the same species. In the analysed material, Selliporella donzellii var.gallaeformis is present with variously oriented sections and frequently preserved only by the outer, peripheral parts of the thallus (Pl. III,fig. 13a;Pl. X,, with more or less preserved secondaries.This makes a more detailed insight into the inner morphology impossible, particularly for the primaries, and also prohibits obtaining more numerous biometric parameters and their mutual relationships.The outer diameter (D) can reach 5 mm.As a rule, the central cavity is secondarily widened through destruction of the primaries and the proximal parts of the secondaries (Pl. X,Pl. XIII,figs. 1,4,6), most probably because of poorly developed calcification in this part of the alga (Pl. X,fig. 9;Pl. XI,figs. 7,9;Pl. XIII,fig. 8).Only a few sections (Pl. X,fig. 9;Pl. XI,figs. 7,9;Pl. XII,fig. 8) enable partial, but insufficient, insight as to the shape and dimensions of the primaries.The impression is, they are much larger, more irregular, and, more often than in the typical variety, proximally compressed, both in the case of the laterals of the same whorl and those of the neighbouring whorls, which makes questionable the existence of an integral inner calcareous envelope, suggesting, instead, its honey-combed structure.
Secondary laterals are of the piriferous type, and because of the destruction of their proximal parts, their growth in pairs and the relationship with the primaries are only rarely observable.Thus, these features make the main and recognizable characteristics of the new variety.In sections, the visibly piriferous secondaries are very large, having much larger diameters than the same values in the typical variety, and are of a different shape, being distinctly piriferous (Pl. X,figs. 2,5;Pl. XI,figs. 4,9), baggy elongated (Pl. X,fig. 8;Pl. XI,figs. 1,8;Pl. XII,, or irregular (Pl. X,figs. 1,4;Pl. XI,fig. 7;Pl. XII,, and different shapes may appear in the same thallus.Secondary laterals of the same pair, in the typical variety being distinguishable by different diameters (lower ones are larger and with larger diameter, upper ones thinner), in this variety this distinction can be seen only in a few sections (Pl. X,fig. 3 top), so this feature remains unclear.The secondaries are distinctly swollen in the first third or half of their total length, except for those that are baggy or irregularly shaped (Pl. X,figs. 2,6,9;Pl. XII,fig. 8).More distally, more or less bent upwards, they, either gradually or abruptly, taper into spiny terminations of individual calcareous envelopes.Because of being swollen, the secondaries of both the same whorl and of the neighbouring whorls are tightly pressed together, compressing each other and leading to vertical and lateral deformations.In tangential sections or in part of the tangential sections, vertical or approximately vertical sections of laterals appear as more or less rounded (Pl. X,fig. 3;Pl. XI,, polygonal or irregular, sometimes distinctly deformed pore shapes (Pl. X,part. fig. 6;Pl. XI,figs. 4,6;Pl. XII,fig. 3).Individual circular bodies, 0.1 mm in diameter can be observed, dispersed in the secondaries' cavities, only rarely grouped together within a common envelope, elliptical in section, with longer axis of 0,24-0,28 mm, shorter axis of 0,15-0,17 mm, and 6-?10 particles in a group (Pl. XI,fig. 5;Pl. XII,arrow).These circular bodies are probably cysts.

Pl. XIII -XVI
The species name derives from the spiky segments, which give such an appearance to the whole thallus.
Type stratum contains numerous algal remnants in algal fenestral biomicrites with corrosion cavities, geopetal internal sediment and microcrystalline cement.Sporadically late diagenetic dolomite appears.The sedimentary environment is determined as the upper intertidal zone with vadose diagenesis and shortterm emersions with palaeokarstification.
Holotype: Longitudinal, slightly oblique section in slide SB-8B/12, figured in Pl.XIV, fig. 2. Isotypes are represented by variously oriented sections, figured in Pls.XIII-XVI.The entire material of Branko Sokač's personal collection in the Croatian Geological Survey will be permanently stored, after publication, in the Croatian Natural History Museum, Zagreb.
Diagnosis: Cylindrical, slightly claviform skeleton, distinctly articulated; comparatively regular central cavity slightly constricted in the level of whorls and slightly widened between neighbouring whorls, situated rather far apart.Each article bears one whorl of ramifying laterals.Primary laterals are small, tuberous or elongated, bearing secondaries in a finger-like arrangement.The number of laterals per whorl increases from the basal to upper parts of the thallus.Secondary laterals of the piriferous type, with variously inclined growth directions and distally indi-vidualized calcareous envelopes give the alga a distinctly spiky (spinose) appearance.
Description: Generally cylindrical skeleton is distinctly articulated.Slightly claviform shape is due to gently but gradually increasing of the segments' outer diameter from the basal to the top parts (Pl.XIII, fig.1).Each article represents the calcified part between the ramified laterals of the same whorl.The distance between consecutive whorls is relatively large, but varies from specimen to specimen.Height and diameter of individual articles gently increases from the basal to the top part of the thallus, depending on the number, length, and inclination of the laterals.(Pl.XIII, fig.1).The calcareous envelope between the segments is the thinnest immediately above the lower segment and slightly thickens going toward the upper one, thus acquiring the shape of an inverted cone which passes, more or less abruptly, into the next (superimposed) segment (Pl. XIII,figs. 3,(5)(6)Pl. XIV,5).
The calcareous skeleton is composed of grainy calcite (sparite), bordered by thin, black, micritic envelopes.Sparry crystals represent the filling of the mould cavity, which remained after the primary, most probably aragonitic, skeleton, was dissolved.A thin micritic lining, enveloping the central cavity and the inner parts of laterals, is, generally, of very uniform thickness (Pl. XIII,fig. 1 lower part;Pl. XIV,(5)(6)Pl. XV,figs. 6,(8)(9)(10)(11)Pl. XVI, and possibly represents the primary micritic algal envelope.In places, this micritic envelope is of uneven thickness, sometimes in the interior of the thallus and more frequently on the outer wall, being probably the result of the activity of endolithic and epilithic microbes.
The euspondyle character of the species is pronounced by clearly visible, mutually separated whorls, which, in the basal parts, bear undivided laterals, and in the upper parts, ramifying ones.The unramified, piriferous laterals of the basal parts of the thallus, are inclined steeply upwards (Pl.XV, fig.8 5) and from which in finger-like arrangement, piriferous secondaries grow out.In spite of the large number of variously oriented sections, the relationship between the proximal swelling of the primary lateral and the secondary laterals, remain unclear.The piriferous secondaries, directed toward the outer surface, grow in various directions, directed both upwards and downwards (Pl. XIII,figs. 1,(4)(5)(6)Pl. XVI,.In segments with ramified laterals, in different planes of section, the visible number of the secondaries per primary lateral varies from 3 to 4 (Pl.XIII, figs.[4][5]Pl. XV,figs. 1,4,6).In deeper tangential sections of individual segments, in the supposedly upper parts of the thallus, the pores suggest a bundle of as much as five secondaries (Pl. XIV,fig. 8;Pl. XV,fig. 12), which, however, remains questionable with regard to the possibility of intergrowth of neighbouring laterals.Individual calcareous sheets of the secondaries distally separate, becoming independent and sticking out like spines.The spines are fragile and the peripheral parts of the thallus are therefore partly or completely eroded, which makes the full value of the outer diameter (D) inadequately defined.
Similarities and differences: Selliporella cornutuformis n. sp.includes the main characteristics of the genus, comparable to the type species: euspondility, unramified or ramified laterals depending on the growth age of thallus (lower or upper part), distally individualized secondaries, articulation of the skeleton, and similar values of biometric parameters.In addition to the similarities, specific characteristics of the two species enable their clear separation.Selliporella cornutuformis n. sp. is characterized by a much larger distance between the neighbouring whorls, strongly pronounced alternation of articles, mutually connected by conical parts of the thallus below the whorls along the entire length of the skeleton, which is lacking in the upper parts of Selliporella donzellii.In the upper parts of the type species, the central cavity is often secondarily widened, due to erosion of poorly calcified densely arranged whorls, and clearly bordered by a micritic envelope in the lower parts of the thallus, as distinct from the new species, in which the central cavity is clearly delimited along the whole length, with constrictions at the level of whorls and slight widening in the intervals between the whorls.The other main difference between the two species concerns the shape of the primary laterals and the number of the secondaries.In the type species, the laterals in the upper part of the thallus grow out in pairs, the lower lateral being, as a rule, larger and distally more or less directed upwards, with individualized calcareous envelopes only at their distal ends.In the new species, with only primary laterals in the basal part, with their ramifying in the upper parts, the number of secondary laterals varies from 3 to 4 (questionably 5).As distinct from the type species, in the new species the piriferous secondaries are of more uniform diameter along their length, diverging from each other and directed both upwards and downwards.In the new species, the individualization of calcareous envelopes of the secondaries occurs as early as in the first third or half of their total length, giving the segments a clearly spiky appearance, as distinct from the type species, in which the separation of calcareous envelopes of individual secondaries occurs only at their distal ends.
Stratigraphic position: At all localities where observed, Selliporella cornutuformis n. sp.derives from various levels of the Selliporella donzellii biozone.The accompanying fossil contents, varies from locality to locality.It is most frequently associated with more or less numerous sections of the type species, with clear predominance either of the new species, or of the type species.At the Osojnik locality (sample O-79), in the wealth of algal remains, the type species is represented by both varieties, accompanied by frequent sections of Uragiella ragusina SOKAČ and particularly numerous Salpingoporella croatica SOKAČ (the latter has been wrongly considered synonymous with Salpingoporella annulata CAROZZI by CARRAS et al., 2006, p. 160).Based on foraminiferal assemblages from both under-and overlying beds, VELIĆ (2005VELIĆ ( , 2007) ) defines the range of the type species Selliporella donzellii SARTONI & CRESCENTI in the Mt.Biokovo area as extending from the early Bajocian to the late Bathonian.This also defines the stratigraphic range of the new species.
Note on the generic attribution of the species originally described as Triploporella neocomiensis RADOIČIĆ, 1963 The generic attribution of the species originally, but invalidly, described as Triploporella neocomiensis RADOIČIĆ, has been, for years past, considered by several authors.Most lately it was ascribed to Selliporella by BUCUR & SĂSĂRAN (2003), which motivated us to include it in this paper.
Diagnosis of Triploporella neocomiensis, as described by RADOIČIĆ (1963), represented this alga by an articulated thallus and with a broad central cavity.Each article corresponds to one whorl of 16 spherical, somewhat laterally compressed, primary laterals, each bearing a bunch of about 10 secondary laterals of variable length.At the same time, while the paper of RADOIČIĆ (1963) was in press, PRATURLON (1964) established Diplopora johnsoni, with approximately identical characteristics.This great similarity between the two species, prompted BUCUR & SĂSĂRAN (2003) to publish comparable, side by side, tables of their biometric parameters and the description of important morphological characteristics, leaving the conclusion of their identity (i.e., synonymy), open, with the recommendation to restudy the type material of Diplopora johnsoni PRATUR-LON.If this recommendation is accepted, it would question the correctness of a number of previous emendations and novae combinationes of numerous species belonging to various genera.In our opinion, Triploporella neocomiensis RADOIČIĆ, 1963, in spite of minor differences in the original author's description, gains its validity only in the paper of RADOIČIĆ (1975), thus being clearly the younger synonym of Diplopora johnsoni PRATURLON, 1964.The generic attribution of these species, which were in earlier papers attributed to various genera, suggests the necessity of further analysis, based on both a comparison of the literature data and the analysis of our material, collected from the Lower Cretaceous deposits of Mt.Dinara and the island of Mljet.
The generic attribution of Triploporella neocomiensis RADOIČIĆ was first questioned by GRANIER (1988).He disputed its attribution to Triploporella and ascribed it formally (though questionably) to the genus Pseudoclypeina as Pseudoclypeina?neocomiensis RADOIČIĆ, 1963 n. comb., based on the similarity of its morphology with that of Pseudoclypeina crnogorica RADOIČIĆ, but without detailed discussion.GRANIER & DELOFRE (1993), however, did not comment on its generic status and thus retained its original name.This possible abandoning of GRANIER's opinion (1988) and following emendation of the generic diagnosis of Selliporella (BARATTOLO et al., 1992) probably prompted further re-investigation of the generic attribution of Triploporella neocomiensis.Thus YILMAZ (1999), on the basis of the similarity of its morphological characteristics with the emended diagnosis of the genus Selliporella, mentioned it, informally, under the name Selliporella cf.neocomiensis RADOIČIĆ.Similarly, it will be informally ascribed to Selliporella by SĂSĂRAN & BUCUR (2001).BUCUR & SĂSĂRAN (2003) compared the emended diagnosis of the genus Selliporella with morphological characteristics of Triploporella neocomiensis RADOIČIĆ and proposed to be included into the genus Selliporella, introducing it, formally, as Selliporella neocomiensis (RADOIČIĆ, 1975non 1963) n. comb. In this comparison BU-CUR & SĂSĂRAN (2003) accept the trichophorous type of laterals as the main diagnostic feature defining its assignment to the genus Selliporella, referring mainly to the reconstruction of the branches in RADOIČIĆ (1963, fig.1), which, however, cannot be accepted as an accurate representation of the illustrated sections.Examining the illustrated sections of both the species originally described as Triploporella neocomiensis and the identical Diplopora johnsoni does not enable a decisive conclusion to be reached on the trichophorous type of secondary laterals, because their distal ends are not preserved in a single one of the rather numerous illustrated sections (RADOIČIĆ, 1963, Pls. 1-5;PRATURLON, 1964, figs. 12-16;JAFFREZO, 1974, Pl. I, fig. 4, Pl. II, figs. 11-12;LUPERTO-SINNI & MASSE, 1986, Pl. 3, figs. 4-5;MANCINELLI, 1992, Pl. II, figs. 8-10;LUPERTO-SINNI & MASSE, 1993, Pl. 1, figs. 9-10).Though in the description of Diplopora johnsoni the author mentions long, thin (i.e., trichophorous) laterals, he later wrote that they sometimes present distally a sharp widening, continuing into thin assimilatory filaments.Also, the existence of trichophorous type secondaries cannot be deduced from sections illustrated in the paper by BUCUR & SĂSĂRAN (2003, Pls. I-III), to which the authors do not refer; furthermore, the sections (Pl.II, fig. 1 top; enlarged details in the same plate, figs.[7][8][9], by the club-shaped primaries and the pores of the secondaries, appear very close to some sections of Pseudoclypeina? crnogorica RADOIČIĆ, 1972, emend RADOIČIĆ, CARARAS & CONRAD, 2013. However, BUCUR & SĂSĂRAN (2003) did not comment on the comparison between those two morphologically similar species, attributed to different genera.As the type of the secondaries (interpreted as trichophorous), though questionable, was considered to be decisive to the generic attribu-tion, so their number in a tuft on the primary lateral, too, remained questionable.According to comparative table in BUCUR & SĂSĂRAN (2003, table 1), the number of secondaries varies from 7 to 10. Analysis of the illustrated sections in their paper suggests that the number is maybe lower (5)(6) Some of the published sections suggest the possibility of tertiary laterals (RADOIČIĆ, 1963, Pl. 1, fig. 1 topmost part).A similar situation occurs with the section figured in BUCUR & SĂSĂRAN (2003, Pl. III, fig. 10), if it refers to the same form.The same question of the number of secondaries and the existence of tertiaries remains unanswered in the description of Diplopora johnsoni PRATURLON.
In conclusion, there are some unclear points in the descriptions of Triploporella neocomiensis and Diplopora johnsoni, in which some mentioned morphological characteristics seem more to reflect the authors' impression than to be confirmed by the figured sections.All these suggest that an emended description and generic attribution are needed, more so because of our conviction of the two species being identical.
We consider, on the base of the analysis of our material and the analysis of published illustrations, together with the fact that we changed the diagnosis of the genus Selliporella, that the characteristics of this alga fit best to the genus Pseudoclypeina RADOIČIĆ (1970).BUCUR (2014) discussed the characteristics of the genus Pseudoclypeina based on the shape of the primary branches, their biometric relationship with the secondary branches and the type of calcitization of the skeleton which is in three species assigned to the genus Pseudoclypeina represented by the yellowish fibrous calcite (P.cirici, P. farinacciae, and P. distomensis).As for the species P. crnogorica, the BUCUR (2014) thinks that is most likely to be affiliated to Selliporella, based on the similarity to S. neocomiensis.We think that, beside other features, the shape of the primary branches of the investigated species is coherent with that of the genus Pseudoclypeina and is analogues to that of the type species P. cirici.A variety of branch shapes can often be seen in species of same genera (eg in the genus Dissocladella and Palaeodasycladus).As regards the calcitization of the skeleton, CONRAD & VAROL (1990) showed that it can be different in species of the same genus (eg the genera of Clypeina and Salpingoporella).BERGER et al. (2003) showed, based on genetic research, that the genus Acicularia, by then distinct from the genus Acetabularia by the type of calcification, is genetically identical to it and thus represents a synonym.All this excludes the type of calcitization as a reliable generic characteristic, although it may serve at the species level.
Bipartite laterals are arranged into distinctly and regularly well-spaced whorls.Each whorl corresponds to one article of the skeleton, formed by the amalgamation of individual calcareous sheets of tufts of neighbouring secondary laterals from the same whorl (Pl. XVII,figs. 1,4,6;Pl. XVIII,8;Pl. XIX,6).Primary and secondary laterals are clearly distinguishable.The primaries, slightly inflated and approximately globular in shape, vary only negligibly (Pl. XVII,Pl. XVIII,figs. 2,5;Pl. XIX,figs. 1,5,7).Each primary lateral bears a tuft of secondaries, which were, in sections illustrated in previous papers poorly defined, mostly interpreted as being trichophorous in shape.Each bundle of secondary laterals, grown out of an individual primary lateral, consists of 5-6, possibly 7-8, individual secondaries, undoubtedly visible in deeper tangential sections, cutting through their proximal parts (Pl.XVII, fig.4; Pl.XVIII, figs.[2][3][4][6][7]Pl. XIX,figs. 3,6).Starting from their initial point of growth, going distally they are slightly inclined upwards or downwards.Generally of a phloiophorous shape, they slightly widen distally (Pl. XVII,Pl. XVIII,Pl. XIX,figs. 1,4,7).In some sections, ring-like constrictions of secondaries may be visible, though indistinctly, possibly indicating their articulation (Pl. XVII,Pl. XVIII,fig. 8;Pl. XIX,fig. 8).The outer ends of calcified tufts are typically eroded, thus making it impossible to gain a full insight into the distal ends of the secondaries.The large number of small pores in distal tangential sections, cutting through individual tufts (Pl. XIX, fig. 3;also RADOIČIĆ, 1963, Pl. 1, fig, 1 top;PRATURLON, 1964, figs. 12, 14 bottom), suggests the possible existence of tertiary laterals, yet to be undoubtedly proven.This possibility is also indicated in some of our sections, in which, in their outer marginal zone, possible traces of tertiaries can be discerned (Pl. XVII,fig. 7; Pl.XIX, fig.7).Their origin can only be supposed by the existence of tiny tufts of short tertiaries.Thus the question of tertiary laterals remains open in the focus of future investigations of this interesting alga.
Stratigraphic position: Determination of the stratigraphic range of Pseudoclypeina johnsoni (PRATURLON) in Lower Cretaceous deposits of the coastal Dinarides in southern Croatia is based on discoveries of associated or superposed fossil assemblages in the investigated localities on Mt.Dinara and on the island of Mljet.
The sample from the Mljet Island (Mlj-46) comes from a poorly fossiliferous interval, typical of continuous shallow water sedimentation on a carbonate platform.The stratigraphic position can only be intermediately defined.In the analysed column, the sample Mlj-46 is situated about 30 m below the first occurrence of Campanellula capuensis DE CASTRO, accompanied by rare sections of Falsolikanella danilovae (RADOIČIĆ) and Salpingoporella genevensis (CONRAD); immediately upwards, the algal assemblage gets richer, with typically Barremian species.Because Campanellula capuensis in this area is characteristic of a narrow zone (taxon-range zone, VELIĆ, 1988VELIĆ, , 2007) ) transitional from the Late Hauterivian to the Barremian and because in the interval between the Mlj-46 sample and the beginning of the above mentioned zone Salpingoporella annulata gradually disappears, the stratigraphic position of Pseudoclypeina johnsoni on the Mljet locality can be ascribed to a Middle Hauterivian level.

ACKNOWLEDGEMENT
It is our pleasure to thank most cordially our colleagues Ivan GALOVIĆ, Ivo VELIĆ, Božo PRTOLJAN and Igor VLAHOVIĆ, for field work and collecting the copious material used in this paper.Moreover, we thank Ivo Velić for the determination of foraminiferal assemblages and explanation of their stratigraphic ranges.Thanks to Ivan GUŠIĆ for translation and Judith Mc- Plate XIII

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Selliporella cornutuformis n. sp. 1 Longitudinal-tangential section.Slightly claviform thallus with noticeable widening and destruction of the central cavity.Undivided pirifer laterals in the basal part with short segments which are developed upwards into dividing laterals, with an increase in the number of dense and differently directed secondary laterals with a significant increase in the height of the segments.Slide: PPB-125, x12,5.