(Belarussian Part): Suborders Ceramoporina, Esthonioporina, Amplexoporina, Halloporina

Geo log i cal Quar terly, 2002, 46 (4): 411–434

Mid dle Or do vi cian bryozoa from the Podlasie-Brest De pres sion (Belarussian part): suborders Ceramoporina, Esthonioporina, Amplexoporina, Halloporina

Victor PUSHKIN

Pushkin V. (2002) — Mid dle Or dovi cian bryozoa from the Podlasie-Brest De pres sion (Belarussian part): suborders Ceramoporina, Esthonioporina, Amplexoporina, Halloporina. Geol. Quart., 46 (4): 411–434.

Bryozoa (23 species ) from many boreholes in the Belarussian part of the Podlasie-Brest Depres sion and some adja cent areas of the East Eu ro pean Plat form are de scribed. Only bryozoa from the orders Cystoporida (suborder Ceramoporina) and Trepostomida (suborders Esthonioporina, Amplexoporina and Halloporina) are repre sented. Four spe cies and one family are described as new. The gen era Anolotichiina Pushkin, 1992 and Minutolunaria Pushkin, 1992 are redescribed. The spe cies de scribed occur in the Llanvirn (Azeri-Kukruse Regional stages) and Caradoc (Idavere-Oandu Regional stages). The results sup port the hypoth e sis that the study area rep re sented an in de pend ent biogeographical re gion of the Bal tic prov ince, cor re spond ing to the Brest-Volyn confacies during the Llanvirn and Caradoc.

Vic tor Pushkin, Belarussian Geo log i cal Pros pecting Re search In sti tute (BelNIGRI), Belarus, Minsk, 220114, Staroborisovsky tract, 14 (receiv ed: July 25, 2001; accepte d: April 18, 2002).

Key words: Podlasie-Brest De pres sion, Or do vi cian, bryozoa, tax on omy, biogeography.

INTRODUCTION sp. nov.) are regard ed as new. The gen era Anolotichiina Push- kin, 1992 and Minutolunaria Pushkin, 1992 are redescribed. As a whole, bryozoa from the Podlasie-Brest De pres sion are simi lar to those of the north ern (the Bal tic-Ladoga Glint) and The Or do vi cian de pos its of the Belarussian part of the south ern (north west ern Belarus, Lith u a nia, Lat via) parts of the Podlasie-Brest Depres sion are pene tra ted by many boreholes Bal tic ba sin (Fig. 1), but differ in the presence of rela ti vely nu - (Ropot and Pushkin, 1987; Pushkin, 2001; Fig. 1). These are merous endem ic (“Podlasie-Bre st”) el em ents. Thus, of 23 spe- rel a tively shal low-wa ter de pos its: mas sive lime stones with thin cies of bryozoa descri bed, 6 specie s are estab li shed only in the in ter calated marl layers. The rocks con tain (es pe cially in the Podlasie-Brest De pres sion: Acanthoceramoporella brestica sp. upper part of the succes sion) num erous skel etal rem ains of in- nov., Anolotichiina tabulatiformis (Pushkin), Minutolunaria ver te brates: cri noids, brachi o pods, bryo zoans, trilobites and illustris sp. nov. (also dis covered in Podolia), Amplexopora others. Bryozoa have been studied exten sive ly (Pushkin, 1973, angustiformis sp. nov., Atactopora gregariaformis sp. nov. and 1975, 1976, 1977a, b, 1981, 1987a, b, c; Pushkin and Hallopora mckinneyi sp. nov. The species listed are not de - Modliński, 2002). The most widesprea d specie s of bryozoa are scribed from other parts of the Balti c basin. descri bed in this paper. As many of the specie s descri bed have been discov ered in other parts of the East Euro pean Platform , in for mation is given about these ar eas in the “Oc cur rence” sec - GEOLOGICAL SETTING tion. In addi ti on, some specie s from these loca ti ons are illus - trated in Fig ures 2–9. Only bryozoa from the orders Cystoporida (suborder Ceramoporina) and Trepostomida The Or do vi cian de pos its in the Podlasie-Brest De pres sion of (suborders Esthonioporina, Amplexoporina and Halloporina) Belarus are rep re sented by rela tively thin (to 40 m) mostly car - are de scribed in this pa per. One family bonate rocks (limestone s and marls). At the base of the sec tion (Acanthoceramoporellidae) and four spe cies (Acanthoceramo- there is a layer (up to 1.5 m thick) of green glauconitic sandstone porella brestica sp. nov., Minutolunaria illustris sp. nov., (Billingen Regional Stage). The Ordo vi cia n is know only from Atactopora gregariaformis sp. nov. and Hallopora mckinneyi bore holes (Fig. 1), the major it y complet ely cored. The thickness 412 Victor Pushkin

A E 2 S 3 Ta llinn St. Petersburg C 1 I T L A 2 B ESTONIA 1 Novgorod

Pskov 3 RUSSIA Riga LATVIA

4 5 6 LITHUANIA 7 14 16 13 15

. Viteb s k

S 8 12

U 9 Vilnius 17 R 10 11

D Minsk 19 N

A 20 L 21

O BELARUS 22 P 24 25 23 28 26 27 29

30 Zhabianka Kobrin Brest 31 Terespol UKRAINE 32 0 50 100 km 0 10 20 km

boreholes outcrops present extent of the Ordovician deposits country border

Fig. 1. Sketch of the loca tion of the area inves ti gated

Boreholes: 1 — Laeva 6, 2 — Chudovo 41, 3 — Serebryaniki 1, 4 — Atashiene 9, 5 — Ludza 15, 6 — Vishki 25, 7 — Butkunaji 241, 8 — Vilkavishkis 129, 9 — Kibartaji 14, 10 — Ilgaji 54, 11 — Tauchenis 49, 12 — Otskovichi 5, 13 — Vidzy 1, 14 — Vangishki 205, 15 — Richany 209, 16 — Verkhnedvinsk 1, 17 — Malye Krasniki 1, 18 — Deshevichi 27, 19 — Lesovchitsy 25, 20 — Vysokoe 1, 21 — Borstchovo 10, 22 — Rataychitsy 12, 23 — Morozovichi 16, 24 — Novoselki 29, 25 — Pribugskaya 17, 31, 26 — Orlya 28, 27 — Kustinskaya 1-op, 28 — Turna 5, 29 — Zhabinka 3, 30 — Brest 9, 31 — Skveriki 1, 32 — Stradech 17; outcrops: 1 — Aluvere quarry, 2 — Lopukhinka vil lage, 3 — Popovka River of the succes sion gradu all y de creases from 40 m in the west to The bryozoa in the Belarussian part of the Podlasie-Brest noth ing in the east. This trend is par alleled by a de crease in clay Depres sion oc cur from the base of the Dolbnev For ma tion content (reduced num ber of marl lay ers). The Ordo vi cia n depos - (Azeri-Lasnamyagi regional stages) repre sent ed by hom oge - its of the Podlasie-Brest Depres sion of Belarus repre sent the neous massive limestone s overly ing red limestone s of Zhabin- Arenig, Llanvirn and Caradoc Se ries, i.e. Billin gen (= Latorp) to ka For ma tion (Ta ble 1). The abundance of bryozoa col o nies Oandu (base) re gional stages (Ta ble 1). Un der ly ing (Pakerort (and other inver te brat es) gradu all y increa ses up the secti on. Regional Stage) and overly ing (Rakvere-Porkuni re gional In the Dolbnev For ma tion (mid dle Llanvirn) bryozoa are stages) de pos its are ab sent. De pos its of Oandu Re gional Stage rep re sented by hemi spher i cal and nod u lar col o nies of has been found only in some western boreholes near the Pol ish trepostomids includ ing (from more to less abundant) : boundary . In the east of the area the upper part of the sec tion has Mesotrypa, Esthoniopora, Orbipora, Dianulites, Diazipora. been gradu all y re moved by erosion. Fig ure 1 shows the dis tri bu - Up the sec tion (Lesovchitsy, Vidomlya and Lystchitsy for mation of boreholes and outcrops of the East Euro pean Plat form in tions) (upper Llanvirn, lower and middle Caradoc) the quanti ty which the bryozoans descri bed were found. Ta ble 1

Stratigraphi cal dis tribu tion of de scribed species of bryozoa in the Ordo vi cian of the Podlasie-Brest De pres sion

Series ARENIG LLANVIRN CARADOC Re gional Stage Billingen Volkhov Kunda Azeri Lasnamyagi Uhaku Kukruse Idavere Jykhvi Kejla Oandu B B B C C C C C D D D M

I II III Ia Ib Ic II III I II III i d d l

For ma tion Leetse Pribug Zhabinka Dolbnev Lesovchitsy Vidomlya Lystchitsy e

O r

Ceramopora explicata Pushkin, 1976 d o v i

Favositella ? exserta Bassler, 1911 c i a n

Acanthoceramoporella brestica sp. nov. b r y

Anolotichiina tabulatiformis (Pushkin, 1976) o z o a

Minutolunaria illustris sp. nov. f r o Esthoniopora communis Bassler, 1911 m

t h e

Dianulites petropolitanus (Pan der, 1830) P o d

Dianulites janischewskyi Modzalevskaya, 1953 l a s i e

Orbipora distincta (Eichwald, 1829) - B r e

Amplexopora angustiformis Pushkin, 1976 s t

Monotrypa undulata (Nichol son, 1875) e p r e

Atactopora gregariaformis sp. nov. s s i o

Diplotrypa petropolitana (Nichol son, 1879) n

( B

Diplotrypa moniliformis Bassler, 1911 e l a r u

Diplotrypa hennigi Bassler, 1911 s s i a

Diplotrypa scalaris L. Nekhorosheva, 1970 n

p a r

Hallopora tolli Bassler, 1911 t ) . . Hallopora mckinneyi sp. nov. . Diazipora milleporacea (Bassler, 1911) Mesotrypa bystrowi Modzalevskaya, 1953 Mesotrypa excentrica Modzalevskaya, 1953 Mesotrypa mesoporica (Pushkin, 1976) Mesotrypa gutta Pushkin, 1987 4 1 3 414 Victor Pushkin and di ver sity of bryozoa grad u ally in creases. To gether with Re marks. — Utgaard (1969) did not conside r hemispher i cal and nodu lar forms there are abundant ramose F. exserta to belong to genus Favositella becaus e it does not and bi fo li ate col o nies, as so ci ated with nu mer ous cri noids, have flexures on the proxi m al side of the lunaria. For this rea- brachi o pods and trilobites, oc cur ring in de tri tal lime stones and son this specie s is only provi sion all y re garded as belong ing to marls. the ge nus Favositella. Oc cur rence. — Llanvirn-Caradoc, Uhaku-Idavere re gional stages. Belarus, Podlasie-Brest De pres sion, SYSTEMATIC PALAEONTOLOGY Lesovchitsy-Vidomlya for ma tions; bore holes: Kustinskaya 1-op, depth 917.5 m (2 spec im ens); Vysokoe 1, depth 842.5 m (1); Pribugskaya 17, depth 824 m (2). Latvia, Vishki 25 borehole, depth 566.6 m (1). Rus sia, Lenin grad region, Chudovo 41 Or der Cystoporida Astrova, 1964 borehole, depth 273–285 m (4); Novgorod re gion, Suborder Ceramoporina Bassler, 1913 Serebryaniki borehole, depth 1057–1111 m (6). Fam ily Ceramoporidae Ulrich, 1882 Ge nus Ceramopora Hall, 1852 Ceramopora explicata Pushkin, 1976 (Fig. 2a–d) Fam ily Acanthoceramoporellidae fam. nov.

1976 Ceramopora explicata Pushkin, p. 5, pl. I, fig. 1. Di ag no sis:Col onies lamellar or ramose. Zooecial openings with 1990 Ceramopora explicata Pushkin, p. 7, pl. I, figs. 2, 3; pl. II, fig. 1. well-developed lunaria. Lunaria and zooecial and exilazooecial walls are pene trated by small styleform struc tures (? minutopores Astrova, 1965 or ? Holotype: No. 12/11-185, Belarussian Geo log i cal Pros pecting Re- styles). Walls of zooecia in exozone thickened, having lamellar search In sti tute (BelNIGRI), Llanvirn, Uhaku Re gional Stage, Dolbnev For - microstructure, usu ally po rous. Di a phragms from zooecial cham bers rare or mation, Belarus, Brest re gion, Lesovchitsy 25 borehole, depth 817 m. ab sent. Exilazooecia usu ally nu mer ous, de vel oped in exozone only. Re vised di ag no sis: Ceramopora with mas sive (hemi spher i cal, nod u lar) and lamellar col o nies; the base of hemi spher i cal col o nies con cen tri - Re marks. — Acanthoceramoporellidae can be disti n - cally wrinkled. Zooecial openings oval and ir regu lar -circular, 0.33–0.50 mm guished from Anolotichiidae Utgaard, 1968 by lamellar in di am e ter. 3–4 zooecial openings per 2 mm. Lunaria well devel oped, horse- microstructure of porous walls, devel op m ent of styleform shoe-shaped, sep arated from wall pores. Walls of zooecia porous, struc tures (? minutopores or ? styles) in zooecial walls and ab - 0.02–0.06 mm thick. Dia phragm s thin, straight, irreg u lar ly de veloped. Exilazooecia nu mer ous (fre quently iso lated from zooecial openings), very sence of cystiform exilazooecia. large, with a di am eter of 0.21–0.85 mm; dia phragm s as in zooecia. Gen era as signed. — Acanthoceramoporella Utgaard, 1968; Anolotichiina Pushkin, 1992; Minutolunaria Re marks.— Ceramopora explicata Pushkin, 1976 Pushkin, 1992. differs from all descri bed spe cies of the genus Ceramopora in having very large exilazooecia. Oc cur rence.— Llanvirn-Caradoc, Azeri-Idavere re gional stages. Belarus, Podlasie-Brest De pres sion, Ge nus Acanthoceramoporella Utgaard, 1968 Dolbnev-Vidomlya for ma tions; bore holes: Lesovchitsy 25, Acanthoceramoporella brestica sp. nov. depth 817 m (2 spec im ens); Kustinskaya 1-op, depth 914.3 m (Fig. 2h–j) (1); Novoselki 29, depth 916 m (1). Lithu a nia, Ilgaji 54 borehole, depth 415.2 m (1). Latvia, Vishki 25 borehole, depth 573.8 m (1). Rus sia: Le ningrad region, village Lopukhinka (2); Et y mol ogy: The name from city Brest, Belarus. Novgorod region, Serebryaniki borehole, depth 1107.3 m (1). Holotype: No. 12/59-63, BelNIGRI, Mid dle Or do vi cian, Kejla Re- gional Stage, Lystchitsy Form ation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 805.3 m. Di ag no sis: Acanthoceramoporella with thin lamellar col o nies; Ge nus Favositella Etheridge and Foord, 1884 zooecial openings right-triangular in outline; lunaria horseshoe-s haped, Favositella ? exserta Bassler, 1911 peripherical ends of lunaria jut out in zooecial cham bers; styleform struc tures (Fig. 2e–g) penetreted thin walls and wide cavi ties around each zooecial opening; 2–3 styleform struc tures. De scrip tion. — Col onies lamellar, thin, thick ness 1911 Favositella exserta Bassler, p. 102, text-fig. 36. 0.7–2.0 mm. Zooecial open ings tri an gu lar, di am e ter Holotype: No. 57177, United States Na tional Museum , Llanvirn, 0.27–0.37 mm, 4.5–5.5 per 2 mm. Walls of both zooecia and Kukruse Re gional Stage, near Jewe, Es to nia. exilazooecia thickened from colony bases, thickness Re vised di ag no sis: Col onies lamellar or irreg u lar-massive. 0.03–0.05 mm. Lunaria dis tinct, horseshoe- or helm et-shaped, Zooecial openings are large, com monly 0.42–0.60 mm, rounded-polygonal or peripherical ends jut out deeply in zooecial chambers. Lunarial irreg u lar , 3–4.5 per 2 mm. Maculae not observe d. Walls of zooecia thin, fre - microstructure lamellate. Length of lunaria 0.13–0.20 mm, quently wavy, with small irreg u lar ly de veloped pores. Lunaria small, tri angu - lar, thick, de veloped in nar row part of openings. Length of lunaria width 0.20–0.28 mm, thickness 0.02–0.04 mm. Walls 0.10–0.17 mm, width 0.07–0.13 mm, thickness 0.04–0.08 mm. Di aphragm s in non-porous. Di a phragms in zooecial chambers ab sent. zooecial cham bers usually absent but sometim es num erous (borehole Exilazooecial openings rela ti vely num erous but not isolat ed Serebryaniki). Exilazooecia rel a tively nu mer ous, di am e ter 0.14–0.52 mm. Walls of exilazooecia usually strongly curved. zooecial openings. Tangen ti al secti ons of exilazooecia rounded or oval. Dia phragm s absent . Stylesform struc tures pen e trate Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 415 walls of zooecia and exilazooecia, have thin walls and wide merous small thorn-like styleform struc tures, pen e trat ing zoo- cav i ties. Di am e ter 0.03–0.05 mm, around each zooecial open- ecial and exilazooecial walls. Lunaria are rep re sented by dense ing 2–3 styleforms. light carbon ate substa nce. Length of lunaria 0.10–0.22 mm, Re marks. — Acanthoceramoporella brestica sp. width 0.16–0.30 mm, thickness 0.03–0.06 mm. Local ly lunaria nov. differs from A. valliensis Karklins, 1984 from the are sepa rat ed from wall pores with a diam eter of 0.03–0.04 Shermanian Stage of the USA (Kentucky ) in having disti nct mm. Walls in endozone thin and curved, in exozone thickened lunaria and tri an gu lar zooecial openings . to 0.03–0.10 mm. Dia phragm s rare, straight, de veloped only in Oc cur rence. — Llanvirn-Caradoc, Uhaku-Kejla endozone. Exilazooecia nu mer ous, small, es pe cially widely re gional stages. Belarus, Podlasie-Brest De pres sion, spread in maculae. Rounded and oval openings of exilazooecia Lesovchitsy- Lystchitsy for ma tions, Pribugskaya 17 borehole, have a diam eter of 0.02–0.18 mm, com monly 0.04–0.10 mm. depth 805.3 m (2 spec im ens); Vitebsk re gion, Vangishki 205 Di a phragms ab sent from exilazooecia. borehole, depth 460 m (1). Lithu a nia, Vilkavishkis 129 bore- Re marks. — Anolotichiina tabulatiformis (Pushkin, hole, depth 949 m (1). 1976) differs from A. laciniatus (Eichwald, 1860) in having ramose colo nies and only one centra l styleform struc ture in lunaria (in lunaria of A. laciniatus 3–5 styleform struc tures are de vel oped (Pushkin and Gataulina, 1992)). Ge nus Anolotichiina Pushkin, 1992 Oc cur rence. — Caradoc, Idavere-Oandu regional stages, Belarus, Podlasie-Brest De pres sion, Vidomlya- Type spe cies: Coenites laciniatus Eichwald, 1860, from the Middle Lystchitsy for ma tions, Novoselki 29 borehole, depth 896.1 m Or do vi cian (Kukruse-Kejla regional stages) of the East Euro pean Platform . (5 spec im ens); Vitebsk re gion, Vangishki 205 borehole, depth Re vised di ag no sis: Acanthoceramoporellidae with lamellar or 433.1 m (2); Lithu a nia: Butkunai 241 borehole, depth ramose col o nies. Zooecial openings with well devel oped lunaria, pene tra ted 654.5–676.0 v (4); Vilkavishkis 129 borehole, depth by small styleform struc tures (? minutopores or ? styles). Frequently in cen tral 944.8–949.0 m (4). Latvia, Vishki 25 borehole, depth part of lunaria one extended styleform struc ture is devel oped. Styleform structures devel oped also in walls of zooecia. Exozone walls thickened, having 557.4–561.2 m (2). Esto nia, Aluvere quarry; Laeva 6 borehole, lamellar microstructure. Pores ab sent or rare. Dia phragms absent from depth 233.0–249.2 m (6). Rus sia, Lenin grad region, Chudovo zooecial cham bers. Exilazooecia num erous, small with rounded transverse 41 borehole, depth 273.0 m (4). shape. Re marks. — Anolotichiina can be disti nguishe d from Acanthoceramoporella in having ramose col o nies, de vel op - Ge nus Minutolunaria Pushkin, 1992 ment of styleform struc tures in lunaria and usuall y non-porous walls of zooecia. Spe cies as signed. — Coenites laciniatus Type spe cies: Anolotichia rhombica Bassler, 1911, Middle Or dovi - Eichwald, 1860; Coeloclema crassimurale Bassler, 1911; cian, Caradoc, Rakvere Regional Stage, Esto nia, Rakvere. Ceramoporella tabulatiformis Pushkin, 1976; Anolotichiina Re vised di ag no sis: Col onies lamellar, ir reg u larly curved. sp. nov. 1; 2; 3 (non descri bed). Zooecial openings with large lunaria, pene tra ted by num erous styleform structures. Locally styleform struc tures also pen etrate zooecial and exilazooecial walls. Walls with nu merous large pores and lamellar microstructure. Dia - phragms rare or absent from zooecial cham bers. Exilazooecia vary ing in abundance, fre quently nu mer ous. Anolotichiina tabulatiformis (Pushkin, 1976) (Figs. 2k–o and 3f, g) Re marks. — Minutolunaria can be disti nguishe d from Anolotichiina in having only lamellar col onies , porous walls and more num erous and irreg u lar ly spaced styleform 1976 Ceramoporella tabulatiformis Pushkin, p. 10, pl. II, fig. 4; pl. III, fig. 4; struc tures in lunaria. text-fig. 4. Spe cies as signed. — Anolotichia rhombica Holotype: No. 12/13-86, BelNIGRI, Caradoc, Jykhvi or Kejla regional Bassler, 1911; A. brevipora Bassler, 1911; A. revalensis stages, Vidomlya Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 896.1 m. Bassler, 1911; Minutolunaria illustris sp. nov. Di ag no sis: Anolotichiina with ramose col o nies; zooecial openings oval or oval-triangular; lunaria trian gu lar with centra l lengthen ing styleform struc ture. Styleform struc tures small, thorn-like; devel oped in zooecial and Minutolunaria illustris sp. nov. exilazooecial walls. Exilazooecia num erous, small, with rounded and oval open ings. (Fig. 3a–e) De scrip tion. — Col onies ramose, di am e ter 1.5–5.0 mm. Exozone from narrow to rela ti vely wide, about Holotype: No. 12/13-71, BelNIGRI, Caradoc, Kejla-Oandu Regional 20–35% of col ony’s di am e ter. Zooecial openings oval or Stage, Lystchitsy Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 892.5 m. oval-tri an gu lar (Figs. 2o and 3g). Length of openings 0.27–0.46 mm, width 0.17–0.25 mm; 3–4 per 2 mm. Lunaria Di ag no sis: Minutolunaria with disc-shaped or lamellar col onies; zooecial openings oval or ir regu lar ly-oval; lunaria large, horseshoe-s haped, al ways well de vel oped, tri an gu lar, with cen tral length en ing com posed of half the zooecial cir cum fer ence; styleform struc tures in lunaria styleform struc ture. Stylefrom struc tures rel a tively nu mer ous large, num erous, (6–9 in each lunaria); walls porous; exilazooecia rela tively in zooecial walls, es pe cially in maculae (Fig. 3g). There are nu - num erous; dia phragm s absent or very rare from zooecia and exilazooecial cham bers. 416 Victor Pushkin

De scrip tion. — Col onies disk-shaped or lamellar Oc cur rence. — Llanvirn-Caradoc, Azeri-Kejla with basal epitheca. Zooecial openings oval or irreg u lar ly-oval, Regional stages. In the Podlasie-Brest De pres sion E. communis large; length 0.44–0.58 mm, width 0.20–0.41 mm; 3.0–4.5 is found in the follow ing bore holes (Dolbnev-Vidomlya for ma- openings per 2 mm. Maculae absent . Lunaria large, horse - tions): Novoselki 29, depth 900.7–922.1 m (19 spec im ens); shoe-shaped, com posed of half of zooecial cir cum fer ence. Pribugskaya 13, depth 830.2–832.3 m (8); Pribugskaya 17, Length of lunaria 0.2–0.4 mm, width 0.3–0.5 mm, thickness depth 808.9–831.2 m (6); Vysokoe 1, depth 830–843 m (8); 0.04–0.09 mm. Lunaria are pene tra ted by num erous styleform Kustinskaya 1-op, depth 909.9–915.2 m (7); Ratajchitsy 12, struc tures (Fig. 3c, d) with diam eter s of 0.04–0.08 mm, each depth 952.5–968 m (3); Lesovchitsy 25, depth 808–813 m (2); lunaria contai ns 6–9 styleform struc tures. Styleform struc tures Borstchovo 10, depth 944 m (1); Brest 9, depth 743 m (1); have in dis tinct bound aries and wide cen tral cav i ties. In dis tinct Orlya 28, depth 1093.0–1100.5 m (3). small styleform struc tures (0.025–0.040 mm) are local ly devel - This specie s is wide spread in the Ordo vi cia n of the East Eu- oped in zooecial and exilazooecial walls. Walls thick ened to ro pean Plat form. 0.03–0.08 mm, pene tra ted by num erous pores of diam eter 0.02–0.05 mm. Exilazooecia rel a tively nu mer ous, with rounded out lines, di am e ter 0.08–0.34 mm. Di a phragms ab sent. Fam ily Dianulitidae Vinassa de Regny, 1920 Re marks. — Minutolunaria illustris (Pushkin, 1976) Ge nus Dianulites Eichwald, 1829 dif fers from M. rhombica (Bassler, 1911) in having num erous Dianulites petropolitanus (Pan der, 1830) exilazooecia and more num erous styleform struc tures in the (Fig. 4a–c) lunaria. Oc cur rence. — Caradoc, Kejla-Oandu regional stages, Belarus, Podlasie-Brest De pres sion, Lystchitsy For ma- 1830 Favosites petropolitanus Pander, p. 105, pl. I, figs. 7–11. tion, Novoselki 29 borehole, depth 892.5 m (1 spec im en). 1877 Dianulites petropolitanus Dybowski, p. 24, pl. I, figs. 4, 5. Ukraine, Dnestr River, vil lage Naddnestryanka, outcrop 279 1911 Dianulites petropolitanus Bassler, p. 232–237 (pars), pl. 2, figs. 4, 5 (non fig. 6); pl. 10, fig. 7 (non figs. 8–11); text-figs. 129 (?), 132 (non figs. (3). Latvia, Atashiene 9 borehole, depth 740.3 m (1). Esto nia, 130, 131). Laeva 6 borehole, depth 142.0–154.5 m (3). 2001 Dianulites petropolitanus Pushkin and Popov, pl. 5, fig. 9; pl. 6, figs. 1–4; pl. 7, fig. 7. 2001 Dianulites petropolitanus Jackcon et al. Lectotype: Spec i men il lus trated by Dybowski, 1877, p. 24, pl. I, figs. Or der Trepostomida Ulrich, 1882 4, 5, Mid dle Or do vi cian, Es to nia. Suborder Esthonioporina Astrova, 1978 Re vised di ag no sis:Dianulites with hemi spher i cal col o nies, con- Fam ily Esthonioporidae Vinassa, 1920 cen tri cally wrin kled and rarely nod u lar. Di am e ter of col o nies 20–200 mm, Ge nus Esthoniopora Bassler, 1911 height 10–50 mm. Zooecial openings regu lar -polygonal, usually 5–6 sides. Esthoniopora communis Bassler, 1911 Maculae well de vel oped. Di am e ter of zooecial openings in intermacular spaces 0.58–0.70 mm, in maculae 0.72–1.05 mm. Intermacular spaces 5–6 per (Fig. 3h–j) 2 mm, in maculae 3–4 zooecial open ings.Walls in dis tinctly-granular, thickness 0.02–0.04 mm. Di aphragm s in zooecial cham bers are dis trib uted rel a - tively regu larly, commontly 0.5–0.7 mm apart. Exilazooecia (? or juve nile 1911 Esthoniopora communis Bassler, p. 260, text-figs. 151–155. zooecia) very rare, having 4-sided outlines and of small di am eter 1978 Esthoniopora communis Astrova, pl. I, fig. 1. (0.15–0.30 mm). Lectotype (pro posed herein): Spec i men il lus trated by Bassler, 1911, Oc cur rence. — Llanvirn-Caradoc, Kunda-Jykhvi text-fig. 152, Caradoc, Jykhvi Regional Stage, Esto nia, Jewe. regional stages of the East Euro pean Plat form (for detai ls see De scrip tion and re marks. — Bassler, Pushkin and Popov, 2001). In the Podlasie-Brest De pres sion 1911, p. 260–263. the specie s descri bed here are found in the follow ing bore holes

Fig. 2. a–d — Ceramopora explicata Pushkin, 1976; BelNIGRI, holotype 12/11-185, Llanvirn, Uhaku Re gional Stage, Dolbnev For ma tion, Belarus, Brest re gion, Lesovchitsy 25 borehole, depth 817 m; tangen tial sections: a — show ing gen eral ar range ment of zooecial with lunaria, and exilazooecial openings, x 40; b — x 10; c — zooecial opening showing zooecial outline and struc ture of lunaria, x 80; d — lon gi tu di nal sec tion show ing zooecial and exilazooecial cham bers, porous walls, rather frequent dia phragm s; x 20. e–g — Favositella ? exserta Bassler, 1911: e, f — BelNIGRI, 12/1-132, Llanvirn, Uhaku Re- gional Stage, Dolbnev Form ation, Belarus, Brest re gion, Kustinskaya 1-op bore hole, depth 917.5 m; e — tan gen tial sec tion show ing gen eral ar range ment of zooecial (with poorly express ed lunaria) and exilazooecial openings, x 40; f — lon gi tu di nal sec tion show ing zooecial and exilazooecial cham bers with rare dia phragm s, x 10; g — BelNIGRI, 12/59-17, Llanvirn, Kukruse Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 824 m, longi tu di nal section show ing zooecial and exilazooecial cham bers and curved walls, x 10. h–j — Acanthoceramoporella brestica sp. nov.: h, i — BelNIGRI, holotype 12/59-63, Caradoc, Kejla Re gional Stage, Lystchitsy Form ation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 805.3 m; h — tan gen tial sec tions show ing gen eral ar range ment of zooecial and exilazooecial openings, x 40; i — lon gi tu di nal sec tion show ing ar range- ment of zooecial and exilazooecial cham bers, x 20; j — BelNIGRI, 12/41-2, Llanvirn, Uhaku Re gional Stage, Krashtaji For mation, Belarus, Vitebsk region, Vangishki 205 borehole, depth 460 m, tan gential section show ing outline of two zooecial openings, and styleform struc tures; x 64. k–o — Anolotichiina tabulatiformis (Pushkin, 1976), BelNIGRI: k–m — BelNIGRI, holotype 12/13-86, Caradoc, Jykhvi Re gional Stage, Vidomlya For ma tion, Belarus, Brest re gion, Novoselki 29 borehole, depth 896.1 m: k — tan gen tial sec tion show ing gen eral ar range ment of zooecial and exilazooecial openings, x 40; l — transverse section show ing genera l structure of a ramose colony, x 20; m — lon gi tu di nal sec tion show ing ar range ment of zooecial cham bers in endozone, and zooecial cham bers in exozone, x 40; n — BelNIGRI, 12/12-102, Caradoc, Idavere Regional Stage, Esto nia, Aluvere quarry, tan gen tial sec - tion show ing gen eral ar range ment of zooecial (with lunaria), exilazooecial openings, and small styleform struc tures, x 40; o — BelNIGRI, 12/74-46, Caradoc, Kejla Re gional Stage, Lith u a nia, Vilkavishkis 129 borehole, depth 944.8 m, tangen tial section show ing genera l ar range ment of zooecial (with lunaria) and exilazooecial openings, x 40 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 417 418 Victor Pushkin

(Lesovchitsy For ma tion): Kustinskaya 1-op, depth 917.5 m (1 Lat via, Vishki 25 borehole, depth 573.8–588.5 m (2); Ludza spec im en); Vitebsk re gion of Belarus: bore holes Vidzy, depth 15, depth 626.2–649.5 m (3) and others. 357.3–361.0 m (2); Vangishki 205, depth 449.1 m (2); Richany 209, depth 309.8 m (2); Otskovichi 5, depth 276.2 m (2). Fam ily Orbiporidae Astrova, 1978 Ge nus Orbipora (Eichwald, 1856) Dianulites janischewskyi Modzalevskaya, 1953 Orbipora distincta (Eichwald, 1829) (Fig. 3k–m) (Fig. 4d, e)

1829 Dianulites de tri tus Eichwald, p. 181. 1829 Orbitulites distinctus Eichwald, p. 180. 1856 Dianulites de tri tus Eichwald, p. 94. 1856 Orbipora distincta Eichwald, p. 93. 1860 Dianulites de tri tus Eichwald, p. 488, pl. XXVIII, fig. 8. 1860 Orbipora distincta Eichwald, p. 484, pl. XXVIII, figs. 6, 7. 1861 Dianulites de tri tus Eichwald, p. 115, pl. VII, fig. 8. 1861 Orbipora distincta Eichwald, p. 114, pl. VII, fig. 7. 1953 Dianulites janischewskyi Modzalevskaya, p. 138, pl. VII, figs. 5, 6; 1877 Orbipora distincta Dybowski, p. 60, pl. 2, fig. 10. text-fig. 18. 1911 Orbipora distincta Bassler, p. 253, pl. 3, fig. 10; text-figs. 144–147. 1978 Orbipora distincta Astrova, pl. II, fig. 1. Holotype: No. 15. Depart ment of Pa le on tol ogy, Geo log i cal Fac ulty of the Uni ver sity of St. Pe ters burg, Echinosphaerites limestone (= Tallinn Lectotype: No. 57328, United States Na tional Museum , Caradoc, Superstage — CI), Volkhovstroj For ma tion, Rus sia, Le nin grad re gion, Jykhvi Regional Stage, Esto nia, Jykhvi (Baron Toll’s es tate) (see Bassler, Volkhov River. 1911, text-fig. 146). Re vised di ag no sis: Dianulites with hemi spher i cal, nod u lar or De scrip tion. — Orbipora with flat tened, discoidal cone-shaped col o nies. Base of hemi spher i cal col o nies con cen tri cally wrin - kled. Diam eter of hemispher i cal colo nies 10–80 mm, height 5–60 mm; maxi - colo nies : di am eter 10–45 mm, height 1–10 mm. The colony mum diam eter of cone-shaped colo nies 20–23 mm, length 30 mm. Latera l height to di am eter rati o is usuall y 1:5–1:1. Base of col ony has a sur faces of cone-shaped col o nies cov ered by lon gi tu di nal epitheca. Zooecial wrin kled epitheca. The colony surface s smooth, without el e- open ings reg u lar-polygonal, 0.25–0.40 mm in di am e ter in intermacular vated maculae. Zooecial open ings po lyg o nal (5–7, usu ally spaces, 0.40–0.60 mm near maculae. Maculae having diam eter 1.2–1.4 mm com posed of exilazooecia (or ? juve nile zooecia), which devel oped mainly in 6-corner), very large, di am eter 0.70–1.00 mm. Approx i m ately maculae, rarely in intermacular spaces. Walls of zooecia and exilazooecia in - 2.5–3 openings per 2 mm. Walls uniform , indis ti nctly granu lar , distinct ly granu lar , slightly curved, thickness 0.025–0.04 m. Di aphragm s in thickness 0.3–0.7 mm. Dia phragm s absent . Styles very num er- zooecial and ? exilazooecial cham bers spread rel ativel y uniform ly, distance be tween di a phragms usu ally 0.5–0.9 mm. ous, 8–16 per 2 mm. Diam eter of styles 0.05–1.00 mm. Styles have thin in dis tinctly gran u lar walls and wide cav i ties. Re marks. — Dianulites janischewskyi Re marks. — Orbipora distincta (Eichwald, 1829) Modzalevskaya, 1953 differs from D. fastigiatus Eichwald, dif fers from O. solida Bassler, 1911 from the Lower Ordo vi - 1829, which also forms cone-shaped colo nies , in having more cian, Kunda Re gional Stage of the Bal tic-Ladoga Glint, in hav - fre quent di a phragms in zooecial and exilazooecial chambers. ing consid er ably more abundant styles and larger zooecia. Oc cur rence. — Arenig-Caradoc, Kunda-Kukruse Oc cur rence. — Llanvirn-Caradoc, Azeri-Jykhvi regional stages of the East Euro pean Plat form; Lower-Middle regional stages of the East Euro pean Plat form. Widely ranging Ordo vi cia n of Arcti c. In Belarus this specie s is found in the spe cies. In the Podlasie-Brest De pres sion this species was Podlasie-Brest De pres sion (Dolbnev-Lystchitsy for ma tions in found in the fol lowing bore holes (Dolbnev-Lystchitsy for ma- the fol low ing bore holes: Morozovichi 16, depth 903 m (1 spec - tions): Kustinskaya 1-op, depth 909–917.5 m (7 spec im ens); i men); Deshevichi 27, depth 639.7 m (1); Zhabinka 3, depth Pribugskaya 17, depth 808.3–820.7 m (4); Vysokoe 1, depth 583 m (1); Pribugskaya 17, depth 808.2–811.5 m (3); Vitebsk 831.6–843.0 m (3); Novoselki 29, depth 893.5–922.1 m (8); re gion, Otskovichi 5 borehole, depth 276.2 m (1); Vangishki Lesovchitsy 25, depth 805.5–821.0 m (6); Orlya 28, depth 205, depth 457.7 m (2); Verkhnedvinsk 1, depth 335.5–337.8 1099.8–1101.0 m (2); Ratajchitsy 12, depth 956–957 m (2); m (2). Lith u a nia, Butkunaji 241 borehole, depth 710.8 m (6); Deshevichi 27, depth 635.1–637.1 m (2). Tauchenis 49, depth 436.4 m (1); Ilgaji 54, depth 414 m (1).

Fig. 3. a–e — Minutolunaria illustris sp. nov.: a, b — BelNIGRI, holotype 12/13-71, Caradoc, Kejla-Oandu Re gional Stage, Lystchitsy Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 892,5 m; a — tan gen tial sec tion show ing gen eral ar range ment of zooecial and exilazooecial openings, x 40; b — lon gi tu di nal sec tion show ing zooecial cham bers, x 20; c–e — BelNIGRI, 12/40-34, Caradoc, Oandu Re gional Stage, Goraevo Form ation, Ukraine, Podolia, Naddnestrjanka village, outcrop 279; c — tan gen tial sec tion show ing large lunaria with styleform struc tures, x 40; d — tan gen tial sec - tion show ing the zooecial openings with lunaria which pierce styleform struc tures, x 64; e — lon gi tu di nal sec tion show ing zooecial and exilazooecial cham bers; x 20. f, g — Anolotichiina tabulatiformis (Pushkin, 1976): f — BelNIGRI, holotype 12/13-86, Caradoc, Jykhvi Re gional Stage, Vidomlya For - mation, Belarus, Brest re gion, Novoselki 29 borehole, depth 896.1 m, longi tu di nal section, x 15; g — BelNIGRI, 12/74-46, Caradoc, Kejla Re gional Stage, Lith u a nia, Vilkavishkis 129 borehole, depth 944.8 m, tangen tial section show ing maculae, protruding exilazooecia and styleform struc tures, well de vel - oped lunaria with centra l styleform struc tures, x 40. h–j — Esthoniopora communis Bassler, 1911: h — BelNIGRI, 12/38-551, Caradoc, Idavere Regional Stage, Belarus, Vitebsk re gion, Vishki 25 borehole, depth 565.1 m, base of colony with concen tri cally banded epitheca, nat u ral size; i —BelNIGRI, 12/38-12, Caradoc, Idavere Re gional Stage, Richany For ma tion, Lith u a nia, Vishki 25 borehole, depth 579.5 m, tan gential section, x 40; j — BelNIGRI, 12/1-117, Llanvirn, Kukruse Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Kustinskaya 1-op bore hole, depth 909 m, longi tu di nal section, x 10. k–m — Dianulites janischewski Modzalevskaya, 1953: k, l — BelNIGRI, 12/6-15, Llanvirn, Uhaku Re gional Stage, Dolbnev For ma tion, Belarus, Brest re gion, Morozovichi 16 borehole, depth 903 m; k — lon gi tu di nal sec tion show ing zooecial and ? exilazooecial cham bers with num erous reg u larly shaped di a phragms, x 10; l — tangen tial section, x 40; m — BelNIGRI, 12/57-2, Caradoc, Idavere Re gional Stage, Lith u a nia, Butkunai 241 borehole, depth 710.8 m, tanential sec tion show ing gen eral ar range ment of zooecial and ? exilazooecial openings, x 40 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 419 420 Victor Pushkin

Suborder Amplexoporina Astrova, 1965 open ings po lyg o nal or ir reg u larly-polygonal (usu ally Fam ily Amplexoporidae Miller, 1889 6–9-corners), di am e ter 0.37–0.64 mm. Ap prox i mately 4–5 Ge nus Amplexopora Ulrich, 1882 openings per 2 mm. Walls dense, straight or slightly wavy, ho- Amplexopora angustiformis Pushkin, 1976 moge nous, thickness com monly 0.010–0.015 mm, but local ly (Fig. 4f, g) increa sed to 0.020–0.025 mm. Dia phragm s very thin, regu lar ly spread, dis tance betwe en dia phragm s 0.23–1.4 mm, com monly 0.35–0.70 mm. Exilazooecia 4–5-corner quite num erous: 1–2 1976 Amplexopora angustiformis Pushkin, p.20, pl. XIV, fig. 3; pl. XV, fig. 1. exilazooecia per 1 zooecia. Di am e ter of exilazooecia Holotype: No. 12/8-65, BelNIGRI, Llanvirn, Uhaku or Kukruse re - 0.10–0.51 mm. Lon gi tu di nal sec tions of exilazooecia are iden - gional stages, Lesovchitsy Form ation, Belarus, Brest re gion, Vysokoe 1 bore- ti cal to zooecial sec tions. hole, depth 842.5–843.0 m. Re marks. — Monotrypa undulata (Nichol son, 1875) Re vised di ag no sis: Amplexopora with ramose col o nies: di am e ter dif fers from M. jewensis Bassler, 1911 from Caradoc, 1.5–5.0 mm, length 5–12 mm. Width of endo- and exozone ap prox i mately Jykhvi-Rakvere regional stages of the East Euro pean Plat form equal. Zooecial openings rounded or oval: maxi m um diam eter in intermacular spaces 0.11–0.16 mm; in indis tinct maculae 0.16–0.20 mm. Approx i m ately 9 in hav ing con sid er able more abun dant di a phragms in the openings per 2 mm.Walls in endozone thin, straight, in exozone thickened to zooecial chambers. 0.05–0.09 mm, with well devel oped dark centra l zone. Dia phragm s thin, dis- Oc cur rence. — Trenton of Canada, USA; tance be tween di a phragms in exozone 0.02–0.15 mm; locall y rare cystiphragms are de vel oped. Styles have rel atively wide cen tral cham ber and Llanvirn-Caradoc, Kukruse-Kejla regional stages of the East indis tinct outlines . Di am eter of styles 0.025–0.040 mm, near each zooecial Euro pea n Platform ; Belarus, Podlasie-Brest De pres sion, bore- opening 4–6 styles. holes: Novoselki 29, depth 912.6 m (1 spec im en — Re marks. — Amplexopora angustiformis Pushkin, Lesovchytsy For ma tion); Pribugskaya 17, depth 809.9 m (1 — 1976 differs from A. angusta Astrova, 1965 from the Middle Lystchitsy For ma tion). Lith u a nia, Vilkavishkis 129 borehole , Or do vi cian of Vajgach Island, in having a wide exozone and depth 948–951 m (2). Latvia, Vishki 25 borehole, depth larger styles with in dis tinct out lines. 570.0–573.8 m (2). Rus sia, Serebryaniki borehole, depth Oc cur rence. — Llanvirn, Uhaku or Kukruse re- 1014.3 m (1). gional stages, Lesovchitsy Form ati on of the Podlasie-Brest De- press ion, borehol es: Vysokoe 1, depth 842.5–843.0 m (3 spec i- mens); Kustinskaya 1-op, depth 909.9 m (1). Fam ily Atactotoechidae Duncan, 1939 Ge nus Atactopora Ulrich, 1879 Atactopora gregariaformis sp. nov. Ge nus Monotrypa Nichol son, 1879 (Fig. 5a–c) Monotrypa undulata (Nichol son, 1875) (Fig. 4h, i) Et y mol ogy: from Atactopora gregaria (Ulrich, 1882). Holotype: No. 12/13-140, Belarussian Geo log i cal Pros pecting Re- 1875 Chaetetes undulatus Nichol son, p. 176. search In sti tute (BelNIGRI), Caradoc, Jykhvi Re gional Stage, Vidomlya For - 1879 Monticulipora (Monotrypa) undulata Nichol son, p. 321, 322, pl. XIV, mation, Belarus, Brest re gion, Novoselki 29 borehole, depth 903.8 m. figs. 3, 4. 1881 Monticulipora (Monotrypa) undulata Nichol son, p.170, text-figs. 32, Di ag no sis: Atactopora with thin lamellar col o nies; zooecial openings 33. rounded or rounded-polygonal; zooecial walls com posed of dark car bonate 1883 Monotrypa undulata Foord, p. 14. ma te rial; di a phragms nu mer ous; exilazooecia very rare; styles num erous of 1970 Monotrypa undulatus Ross, p. 375, pl. 70, figs. 6, 7; pl. 71, figs. 1–6. dif fer ent sizes. Lectotype (proposed herein): Spec im en illus tra ted by Nichol son, 1879, De scrip tion. — Thin lami nar Atactopora, en - p. 321, 322, pl. XIV, figs. 3, 4, Middle Or dovi cian, Trenton, Hudson River crust ing ramose and massive bryozoa col o nies and Group, Canada, Toronto. Echinosphaeri tes. Col onies usuall y pluristratose, thickness of De scrip tion. — Monotrypa with irregular- lay ers 0.1–0.8 mm. Zooecial openings rounded or massive col onies with num erous growth layers. Base of colony rounded-polygonal, di am eter 0.15–0.29 mm. 7.5–8.5 openings cel lu lar. Max i mum size of col o nies 25´25´20 mm. Zooecial per 2 mm. Walls hom oge nous, dense, com posed of dark carbon ate ma te rial, thick ness 0.02–0.03 mm. Di a phragms nu mer-

Fig. 4. a–c — Dianulites petropolitanus (Pan der, 1830), BelNIGRI, 12/1-129, Llanvirn, Uhaku Re gional Stage, Lesovchitsy For ma tion, Belarus, Brest re - gion, Kustinskaya 1-op bore hole, depth 917.5 m: a — tan gen tial sec tion show ing gen eral ar range ment of zooecial openings (alter nation of maculae and intermacular spaces), x 10; b — tan gen tial sec tion show ing gen eral ar range ment of zooecial openings in intermacular space, x 40; c — lon gi tu di nal sec tion show ing zooecial cham bers with num erous dia phragm s, x 10. d, e — Orbipora distincta (Eichwald, 1829), BelNIGRI, 12/1-131, Llanvirn, Uhaku Re- gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Kustinskaya 1-op bore hole, depth 917 m: d — tan gen tial sec tion show ing gen eral ar range- ment of zooecial openings and num erous styles, x 40; e — lon gi tu di nal sec tion show ing zooecial cham bers without dia phragm s, x 30. f, g — Amplexopora angustiformis Pushkin, 1976, BelNIGRI, holotype 12/8-65, Uhaku Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Vysokoe 1 borehole, depth 842.5–843.0 m: f — tan gen tial sec tion show ing gen eral ar range ment of zooecial openings, struc ture of walls, and styles, x 40; g — lon gi tu di nal section show ing the zooecial cham bers with dia phragm s and cystiphragms; x 20. h, i — Monotrypa undulata (Nicholson, 1875), BelNIGRI, 12/13-204, Llanvirn, Kukruse Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 912.6 m: h — tan gen tial sec tion show ing the gen eral ar range ment of zooecial openings, x 40; i — lon gi tu di nal sec tion, show ing zooecial cham bers with num erous dia phragm s and wavy zooecial walls, x 10 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 421 422 Victor Pushkin ous, straight, distanc e betwe en dia phragm s 0.04–0.25 mm. In 0.55–0.70 mm. In intermacular spaces ap prox i mately 3–3.5 each zooecial cham ber 2–8 di aphragm s. Exilazooecia very openings per 2 mm. Walls of zooecia in all parts of colo nies rare, di am e ter 0.04–0.15 mm. Styles nu mer ous, di am e ter thin, straight, of thickness 0.010–0.015 mm. Dia phragm s thin, 0.02–0.08 mm, 3–5 styles near each zooecial opening. usuall y straight, but local ly curved; cystiphragm-like and in- Re marks. — Atactopora gregariaformis sp. nov. clined dia phragm s are observe d. The distanc e betwe en dia - dif fers from A. gregaria (Ulrich, 1882, 1893) from the Upper phragms 0.1–1.0 mm, com monly 0.2–0.5 mm. Mesozooecia Or do vi cian (For ma tion Lorrein) USA (Indi ana) in having rela - quite nu mer ous (2–4 mesozooecia per 1 zooecia), but never tively nu mer ous di a phragms in zooecial chambers and larger com pletely iso lated from zooecial openings. The size of poly g - zooecial openings. o nal (4–6-corner) mesozooecial openings is 0.05–0.40 mm. Oc cur rence. — Caradoc, Idavere-Kejla regional Dia phragms in mesozooecial cham bers fre quent, straight, sep- stages. Podlasie-Brest De pres sion (Vidomlya For ma tion), arat ed by 0.01–0.12 mm. Novoselki 29 borehole, depth 903.8 m (4 spec im ens). Latvia, Re marks. — Diplotrypa petropolitana (Nichol son, bore holes: Vishki 25, depth 552.3 m (1); Ludza 15, depth 603.9 1879) differs from D. densitabulata Modzalevskaya, 1953 (= m (1). D. petropolitana (Nicholson, 1879) — Astrova, 1965, pl. XXVII, fig. 2) from the Upper Ordo vicia n Nabala-Vormsi regional stages of the East Euro pean Plat form in having more rare and uniform ly spreaded straight dia phragm s in the Suborder Halloporina Astrova, 1965 zooecial chambers. Fam ily Halloporidae Bassler, 1911 Oc cur rence. — Wide spread specie s in the Middle Ge nus Diplotrypa Nichol son, 1879 Or do vi cian (Llanvirn-Caradoc, Uhaku-Rakvere regional Diplotrypa petropolitana (Nichol son, 1879) stages) of the East Euro pean Plat form. In the Podlasie-Brest (Fig. 5d–i) De pres sion (Lesovchitsy-Vidomlya form ati ons) found in the fol low ing bore holes: Novoselki 29, depth 893.5–920.0 m (6 spec i mens); Kustinskaya 1-op, depth 913.2–917.5 m (4); Vysokoe 1, depth 826.6–842.0 m (4); Borstchovo 10, depth ?1861 Chaetetes petropolitana Roemer, p. 28, pl. IV, fig. 8. 942.6–946.2 m (2); Ratajchitsy 12, depth 956–966 m (3); 1877 Callopora nummiformis (Hall) Dybowski, p. 14, pl. 5, fig.1. Lesovchitsy 25, depth 810–821 m (3); Deshevichi 27, depth 1879 Monticulipora (Diplotrypa) petropolitana Nichol son, p. 313, pl. XIII, 630.8–640.1 m (4); Orlya 28, depth 1099.0–1097.8 m (7); fig. 3. 1881 Monticulipora (Diplotrypa) petropolitana Nichol son, p. 156, Pribugskaya 31, depth 866.9 m (1). text-fig. 30. 1911 Diplotrypa petropolitana Bassler, p. 313, text-figs. 192–195. 1911 Hallopora ? dybowskii (pars) Bassler, p. 335, text-fig. 212 (non text-fig. 211). 1921 Diplotrypa petropolitana Bekker, p. 44, pl. X, figs. 1–11. Diplotrypa moniliformis Bassler, 1911 1965 Diplotrypa petropolitana Astrova, p. 183, pl. XXVII, fig. 2. (Fig. 5j, k) 1970 Diplotrypa petropolitana Nekhorosheva, p. 74, text-fig. 2. 1978 Diplotrypa petropolitana Astrova, pl. VIII, fig. 2. Lectotype (proposed herein): Spec im en illus tra ted by Nichol son, 1879, p. 313, pl. XIII, fig. 3, Caradoc, Chasmops limestone, Swe den, Ostrogothia (Bassler, 1911, text-fig. 192). 1911 Diplotrypa moniliformis Bassler, p. 321, text-fig. 199. 1921 Diplotrypa moniliformis Bekker, p. 43, pl. IX, figs. 7–9. De scrip tion . — Diplotrypa with massive (usu ally Holotype: No. 57413, United States Na tional Museum , Caradoc, hemispher ical) col o nies. The bases of col o nies are cov ered by a Jykhvi Regional Stage, Esto nia, Kukruse (Baron Toll’s es tate). strongly con cen tri cally wrin kled epitheca. The av er age spec i- mens are 2–3 cm in di am eter and 1–1.5 cm in height. Maxi - De scrip tion. — Diplotrypa with hemi spher i cal or mum diam eter of col onies 10 cm. Col onies surface smooth. nodu lar colo nies of rel ati vely small (0.5–1.5 cm) size. Bases of Zooecial open ings po lyg o nal (usu ally 6–9-corner): av er age di- hemi spher i cal col o nies with con cen tri cally wrin kled epitheca. am e ter in intermacular spaces 0.40–0.55 mm, in maculae Zooecial open ings po lyg o nal (usu ally ir reg u larly-polygonal),

Fig. 5. a–c — Atactopora gregariaformis sp. nov., BelNIGRI, holotype 12/13-140, Caradoc, Jykhvi Re gional Stage, Vidomlya For ma tion, Belarus, Brest re gion, Novoselki 29 borehole, depth 903.8 m: a, b — tan gen tial sec tions show ing gen eral ar range ment of zooecial openings and styles, x 40; c — longi tu - di nal sec tion show ing gen eral struc ture of zooecial cham bers, x 20. d–i — Diplotrypa petropolitana (Nicholson, 1879): d–f — BelNIGRI, 12/13-186, Llanvirn, Kukruse Re gional Stage, Lesovchitsy For mation; Belarus, Brest re gion, Novoselki 29 borehole, depth 914.5 m; d — tan gen tial section showing gen eral ar range ment of zooecial and mesozooecial openings, x 38; e — lon gi tu di nal sec tion show ing gen eral struc ture of zooecial and mesozooecial cham - bers, x 20; f — the same longi tu di nal section, x 38; g — BelNIGRI, 12/29-47, Caradoc, Idavere Re gional Stage, Richany For ma tion, Lith u a nia, Ilgaji 49 borehole, depth 405.6 m, tangen tial section across maculae showing large sizes of zooecial and mesozooecial openings, x 40; h, i — BelNIGRI, 12/41-20, Caradoc, Idavere Re gional Stage, Richany Form ation, Belarus, Vitebsk region, Vangishki 205 borehole, depth 447.5 m; h — lateral view of the colony, x 2; i — base of colo nies, x 2. j, k — Diplotrypa moniliformis Bassler, 1911, BelNIGRI, 12/29-46, Caradoc, Idavere Re gional Stage, Richany For ma tion, Lith u a nia, Ilgaji 49 borehole, depth 407.2 m: j — tan gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; k — longi - tu di nal sec tion show ing gen eral struc ture of zooecial and mesozooecial cham bers, curved dia phragm s in zooecial cham bers, wavy struc ture of walls, x 20. l, m — Diplotrypa hennigi Bassler, 1911, BelNIGRI, 12/4-27, Llanvirn, Uhaku Re gional Stage, Dolbnev Form ation, Belarus, Brest re gion, Zhabinka 3 borehole, depth 742 m: l — tan gen tial sec tion show ing gen eral ar range ment of zooecial and small mesozooecial openings, x 40; m — lon gi tu di nal sec tion show ing gen eral struc ture of zooecial cham bers, lacking (or rare) di aphragm s and small mesozooecial cham bers, x 40 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 423 424 Victor Pushkin

6–9-corner. Maculae absent or indis ti nct. Diam eter of openings m (2 speci m ens); Vysokoe 1, depth 820 m (1); Turna 5, depth 0.32–0.47 mm, 3–4 openings per 2 mm. Walls of zooecia thin, 742 m (1). usuall y strongly and ir regu lar ly curved, thickness 0.01–0.02 mm. Dia phragm s thin, straight, rela ti vely uniform ly spread, dis tance be tween di a phragms 0.2–0.8 mm. Mesozooecia abun- Diplotrypa scalaris L. Nekhorosheva, 1970 dant, but not isolat ed from zooecial open ings. Di am e ter of (Fig. 6a–d) mesozooecia 0.10–0.32 mm, dia phragm s as in zooecial chambers. Re marks. — Diplotrypa moniliformis Bassler, 1911 1970 Diplotrypa scalaris L. Nekhorosheva, p. 77, pl. IV, figs. 3, 4; pl. V, fig. differs from other spe cies of Diplotrypa by strongly and ir regu - 2; text-fig. 3. larly curved zooecial and exilazooecial walls of endo- and Holotype: No. 10161, Cen tral Geo log i cal Mu seum (CGM) in honour exozone of col onies . of F. N. Chernyshev (St. Pe ters burg), Caradoc, Yugor Re gional Stage, Beds Oc cur rence. — Llanvirn-Caradoc, Uhaku-Kejla with Christi an ia subquadrata, North Ural (Paj-Khoj). regional stages of the East Euro pean Plat form. In the Re vised di ag no sis: Diplotrypa with nod u lar and hemi spher i cal Podlasie-Brest Depres sion this specie s has found in the fol low- col o nies. Bases of hemi spher i cal col o nies with con cen tri cally wrin kled epitheca. Zooecial openings rounded or rounded-polygonal, diam eter ing bore holes (Lesovchitsy For ma tion): Novoselki 29, depth 0.27–0.44 mm. About 5–6 openings per 2 mm. Walls straight or slightly 920 m (2 spec im ens); Vysokoe 1, depth 831,6 m (1); Turna 5, curved. Di aphragm s rel ativel y num erous, straight or curved, distance betwee n depth 743.5 m (1); Zhabinka 3, depth 743.5 m (1). Specie s rel a- dia phragm s 0.07–0.85 mm, usually 0.2–0.4 mm. Mesozooecia rela tively nu - tively wide spread on the East Euro pean Plat form. merous, lo cally form one row between zooecial open ings; di am e ter of ir reg u- larly-polygonal mesozooecial openings 0.07–0.34 mm. Di aphragm s frequent, straight, slightly curved of the mesozooecial walls, dis tance be tween di a - phragms 0.06–0.16 mm. Colony bases al most com pletely com posed of mesozooecia or mesozooecia-shaped struc tures with frequent and thickened Diplotrypa hennigi Bassler, 1911 di a phragms (Fig. 6c). (Fig. 5l, m) Re marks. — Diplotrypa scalaris L. Nekhorosheva, 1970 differs from D. petropolitana (Nicholson, 1879) in having nu mer ous, fre quently curved di a phragms in zooecial cham- 1911 Diplotrypa hennigi Bassler, p. 322, text-fig. 200. 1965 Diplotrypa hennigi Astrova, p. 187, pl. XXX, fig. 1, text-fig. 34. bers. Oc cur rence. — Llanvirn-Caradoc, Yugor Re - Holotype: No. 57414, Unites States National Museum , Llanvirn, Kukruse Re gional Stage, Esto nia, near Tallinn (Baron Toll’s es tate). gional Stage of Vajgach Island; Idavere Re gional Stage (Vidomlya Form ati on) of the Podlasie-Brest De pres sion; De scrip tion. — Diplotrypa with nod u lar col o nies. Novoselki 29 borehole, depth 904.0–906.8 m (2 spec im ens); Di am e ter of col o nies 5–15 mm. Zooecial open ings po lyg o nal Belarus, Vitebsk region, Vangishki 205 borehole, depth (usu ally ir reg u larly-polygonal), 5–7-corner. Maculae ab sent or 436.7–439.8 m (2 spec im ens, Richany For ma tion). indis ti nct. Diam eter of openings 0.24–0.38 mm, 5.5–6.5 openings per 2 mm. Walls of zooecia thin, straight or curved, local ly gradu all y curved. Di aphragm s absent or very rare. Mesozooecia rel ati vely num erous (but in some parts of col o - Hallopora Bassler, 1911 nies com pletely absent ): on the aver age 1–2 mesozooecia per 1 Hallopora tolli Bassler, 1911 zooecia. Di am e ter of mesozooecia 0.10–0.21 mm, dis tance be- (Fig. 6e–i) tween dia phragm s 0.10–0.17 mm. Oc cur rence. — Llanvirn-Caradoc, Uhaku-Kejla 1911 Hallopora tolli Bassler, p. 333, text-fig. 1. regional stages of the East Euro pean Plat form. In the Pod- 1941 Hallopora tolli Fritz, p. 564, text-fig. 1. lasie-Brest De pres sion (Lesovchitsy-Lystchitsy for ma tions) 1967 Hallopora cf. tolli Bork and Perry, p. 1382, pl. 176, figs. 2–6. found in the fol lowing bore holes: Kustinskaya 1-op, depth 909 Lectotype: spec i men il lus trated by Bassler, 1911, p. 333, text-fig. 1, Caradoc, Jykhvi Regional Stage, Esto nia, Jewe.

Fig. 6. a–d — Diplotrypa scalaris L. Nekhorosheva, 1970: a, b — BelNIGRI, 12/13-244, Caradoc, Idavere Re gional Stage, Vidomlya For ma tion, Belarus, Brest re gion, Novoselki 29 borehole, depth 904 m; a — tangen tial section, x 40; b — lon gi tu di nal sec tion, x 20; c — BelNIGRI, 12/13-229, Belarus, Brest re gion, Novoselki 29 borehole, depth 906.8 m, longi tu di nal section show ing genera l structure of zooecial cham bers with num erous, fre quent incline d dia - phragms and mesozooecial cham bers with fre quent dia phragm s, x 20; d — BelNIGRI, 12/41-31a, Caradoc, Idavere Re gional Stage, Richany For ma tion, Belarus, Vitebsk region, Vangishki 205 borehole, depth 439.8 m, latera l view of small nodu lar colony, x 2. e–i — Hallopora tolli Bassler, 1911: e, f — BelNIGRI, 12/11-166, Llanvirn, Uhaku Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Lesovchitsy 25 borehole, depth 808 m; e — tan - gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; f — lon gi tu di nal sec tion show ing gen eral ar range ment of zooecial and mesozooecial cham bers, x 20; g, h — BelNIGRI, 12/38-150, Caradoc, Jykhvi Re gional Stage, Vangishki For ma tion, Lat via, Vishki 25 borehole, depth 560.1 m: g —tan gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; h — lon gi tu di nal sec tion, x 40; i — BelNIGRI, 12/50-21, Caradoc, Idavere Re gional Stage, Latvia, Ludza 15 borehole, depth 628.1 m, longi tu di nal section show ing genera l structure of zooecial cham bers, lack ing di a phragms, and mesozooecial cham bers with fre quent dia phragm s, x 15. j–l — Hallopora mckinneyi sp. nov.: j, k — BelNIGRI, 12/13-287a, Caradoc, Kejla-Oandu regional stages, Vidomlya Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 892.5 m; j — tan gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 48; k — lon gi tu di nal sec tion show ing gen eral struc ture of zooecial and mesozooecial cham bers, x 40; l — BelNIGRI, 12/13-263, Caradoc, Jykhvi Re gional Stage, Vidomlya For ma tion, Novoselki 29 borehole, depth 899.3 m, transverse section of ramose colo nies, x 20 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 425 426 Victor Pushkin

De scrip tion. — Hallopora with cy lin dri cal (sau - tion 6–7 openings. Zooecial walls in endozone thin, slightly sage-shaped) or ramose, rarely branched col o nies. Pres ence of curved. In exozone thickness of zooecial walls in creases to exozone is uncle ar. Colony surface s smooth. Di am eter of col o - 0.10–0.17 mm and walls display well-expressed slant- nies 4–8 mm, length 5–20 mm. Maculae not observe d. ing-lamellar microstructure with well-developed dark centra l Zooecial open ings po lyg o nal or rounded-polygonal, di am e ter zone. Di a phragms in endozone usuall y absent (but local ly 0.35–0.51 mm; 3.5–4.5 openings per 2 mm. Walls of zooecia quite abundant) , in exozone alway s 1–5 (usuall y 3–4) straight thin, straight, thickness 0.01–0.02 mm. Dia phragm s usuall y ab - or curved di aphragm s. Mesozooecia quite num erous, two or sent or very rare. Mesozooecia rel ati vely abundant, but not iso- three around each zooecia, devel oped with base of endozone. lated from zooecial open ings. Di am e ter of mesozooecia Di am e ter of mesozooecia varies from 0.05 to 0.34 mm, usuall y 0.12–0.33 mm, dia phragm s straight, distanc e betwe en dia - 0.07–0.15 mm. About colony surface s mesozooecial chambers phragms 0.08–0.16 mm. over grown by a car bon ate sub stance. Di a phragms in Re marks. — This spe cies dif fers from other species mesozooecial chambers straight, frequen t, dis tance be tween of Hallopora in hav ing cyli n dri cal (sau sage-shaped) col o nies them 0.03–0.11 mm. and an in dis tinctly de vel oped exozone. Re marks. — These speci m ens have been ear lier er ro - Oc cur rence. — The species is rel atively wide spread neously descri bed (Pushkin, 1987a) as H. onealli (James, in the Middle Ordo vi cia n of the East Euro pean Plat form. In Es- 1875) and H. ovata (Mc Kinney, 1971) (see synon ym y). An to nia — Uhaku-Kejla re gional stages. Lith u a nia, Butkunai 241 exam ina ti on of these speci m ens with the addi ti on of a new ex - borehole, depth 677.0 m (1 spec im en). Latvia, Vishki 25 bore- ten sive ma te rial (es pe cially from the Kibartaji 14 borehole) has hole, depth 560.1 m (1); Ludza 15 borehole, depth 628.1 m (1). shown that this specie s belongs to the new specie s (H. Rus sia, Serebryaniki borehole, depth 999.8–1043.7 m (3); in the mckinneyi) wide spread in the Middle Ordo vi cia n Podlasie-Brest Depres sion (Lesovchitsy For ma tion): (Idavere-Oandu regional stages) of the East Euro pean Plat - Lesovchitsy 25 borehole, depth 804.8–810.7 m (3); Middle Or- form. H. mckinneyi, sp. nov. differs from H. onealli (James, dovi cia n, Black River Form ati on of Canada (Gaspe); Gattenberg 1875) from the Upper Ordo vi cia n (Cincinnatian) of the North For ma tion of USA (Il li nois State). Amer i can Plat form (Nichol son, 1881; Bassler, 1906; Cumings, 1908; non Ross, 1969) in having a wider exozone of col onies , larger mesozooecia and more rare dia phragm s in zooecial cham bers in exozone; from H. ovata (Mc Kinney, 1971) from Hallopora mckinneyi sp. nov. Chicamauga Group (Trenton) of Ala bam a State USA it differs (Figs. 6j–l and 7a–e) in dis playing larger zooecia and sharply bent zooecial chambers in the transi ti on from endo- to exozone. 1987a Hallopora onealli (James); Pushkin, p. 150, pl.VI, figs. 4, 5. Oc cur rence. — Caradoc, Idavere-Oandu regional 1987a Hallopora ovata (Mc Kinney); Pushkin, p. 151, pl. VII, figs. 1, 2. stages. Belarus, Podlasie-Brest De pres sion (Vidomlya- Et y mol ogy: in honour of Dr. Frank Mc Kinney. Lystchitsy for ma tions), bore holes: Vysokoe 1, depth 820 m (1 spec i men); Novoselki 29, depth 892.5–901.5m (17); Vitebsk Holotype: No. 12/8-48, BelNIGRI, Caradoc, Kejla-Oandu regional stages, Lystchitsy Form ation, Belarus, Brest re gion, Vysokoe 1 borehole, region, Vidzy, depth 331.2 m (1). Latvia, Vishki 25 borehole, depth 820 m. depth 552.3–570.0 m (7). Lithu a nia, Kibartai 14 borehole, Di ag no sis: Hallopora with ramose colo nies; transi tion from endo- to depth 1213.2–1230.5 m (more then 70). exozone of colo nies rela tivel y sharp; width of exozone repre sents 20–30% of branch width; zooecial openings rounded or oval; zooecial walls in endozone thin, slightly curved, in exozone thickened; di aphragm s in endo- and exozone de vel oped ir reg u larly; mesozooecia quite abundant and large with frequent Ge nus Diazipora Vinassa, 1920 straight di a phragms. Diazipora milleporacea (Bassler, 1911) De scrip tion. — Col onies ramose, length of frag- (Fig. 7f–j) ments 10–20 mm, diam eter 2–5 mm. Exozone of col onies quite wide, com prising 20–30% of the width of a branch. Zooecia in 1911 Mesotrypa milleporacea Bassler, p. 201, text-fig. 109. endozone oriente d verti cally, then sharply bent and opens at the 1911 Mesotrypa milleporacea parva Bassler, p. 203, text-fig. 110. surface at an angle of 80–90°. Zooecial openings rounded or 1970 Diazipora milleporacea Nekhorosheva, p. 78, pl. III, fig. 1, text-fig. 5. oval; diam eter betwe en maculae 0.19–0.34 mm (usuall y Holotype: No. 57284, United States Na tional Museum , Caradoc, 0.24–0.30 mm), at maculae 0.30–0.47 mm. Five to seven open- Chasmops lime stones, Swe den, Is land of Oeland, south of Bodahamm. ings per 2 mm along longi tu di nal axes, in perpen dic u lar direc -

Fig. 7. a–e — Hallopora mckinneyi sp. nov.: a–d — BelNIGRI, holotype 12/8-48, Caradoc, Kejla-Oandu regional stages, Lystchitsy For ma tion, Belarus, Brest re gion, Vysokoe 1 borehole, depth 820 m: a, b — tan gen tial sec tions show ing gen eral ar range ment of zooecial and mesozooecial openings and struc ture of wall, x 40; c, d — lon gi tu di nal sec tions show ing gen eral struc ture of zooecial and mesozooecial cham bers and dis po si tion of di a phragms, x 20; e — BelNIGRI, 12/51-82, Caradoc, Oandu Re gional Stage, Lith u a nia, Kibartaji 14 borehole, depth 1213.2 m. f–j — Diazipora milleporacea (Bassler, 1911): f–h — BelNIGRI, 12/59-15, Llanvirn, Kukruse Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 824 m: f — tan gen tial sec tion show ing ar range ment of zooecial and mesozooecial out lines at maculae area, x 40; g — the same sec tion show ing ar range - ment of zooecial and mesozooecial openings at intermacular area; h — lon gi tu di nal sec tion show ing of the dis tri bu tion of di a phragms in the zooecial cham bers, x 40; i, j — BelNIGRI, 12/1-67, age the same, Vysokoe 1 borehole, depth 843 m; i — tangen tial section, x 40; j — lon gi tu di nal sec tion, x 40 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 427 428 Victor Pushkin

De scrip tion. — Col o nies ir reg u larly-mas sive, fre - 1953 Mesotrypa bystrowi Modzalevskaya, p. 114, pl. II, figs. 1, 2; text-fig. 5. 1953 Mesotrypa bystrowi var. tuberculata Modzalevskaya, p.116, pl. II, figs. quently nodu lar , local ly hollow or lamellar. Size 5 mm to 3 cm. 3, 4; text-fig. 6. Zooecial open ings rounded (lo cally ir reg u larly-rounded), di- 1953 Mesotrypa piriformis Modzalevskaya, p.118, pl. II, figs. 5, 6; text-fig. 7. am eter 0.25–0.41 mm, around maculae 0.41–0.65 mm. 1961 Mesotrypa excentrica (pars) Myannil, p. 129, pl. I, fig. 7, 8; pl. VII, fig. Maculae rare, com posed of ac cu mu lations of neozooecia, sur - 3; pl. VIII, figs. 1, 7. rounded by large zooecia, size of maculae 0.7–1.5 mm. Ap- Holotype: No 392, Depart ment of Pa le on tol ogy, Geo log i cal Fac ulty of prox i mately 5–6 zooecial openings per 2 mm in intermacular the Uni ver sity of St. Pe ters burg, Caradoc, Jykhvi Regional Stage, Esto nia, Aluvere quarry. spaces. Walls of zooecia thin, ho mog e nous, thick ness 0.010–0.015 mm. Dia phragm s in zooecial chambers are usu - Di ag no sis: Mesotrypa with mas sive, gen er ally hemi spher i cal col o - nies; base of col o nies cel lu lar; zooecial openings com monly rounded, alway s ally num erous, com monly curved (Fig. 7h, j) (es pe cially fre - in contact with each other; di aphragm s in zooecial cham bers de vel oped very quent on new col ony surface ), aver age distanc e betwe en dia - ir reg u larly, straight or curved; mesozooecia with tri an gu lar-quadrangular phragms 0.02–0.40 mm. In some col onies (or their parts) di a- openings, quite num erous, but not isolate d zooecial open ings; styles small, phragms may be com pletely (or al most com pletely) absent , but short, devel oped only near colony sur face. usu ally are nu mer ous. Neozooecia very num erous, usuall y De scrip tion. — Col onies massive , gener all y com pose small ac cu mu la tions in the cor ners be tween zooecia, hemi spher i cal, rarely ir reg u larly mas sive or nod u lar. Av er age but as a rule are not isolat ed from zooecial openings. In di am e ter of hemi spher i cal col o nies 10–20 mm, height maculae neozooecia form larger ac cu mu la tions (Fig. 7f). Di- 5–10 mm. Maxi m um size of col onies 4–5 cm. Cellu lar bases of am e ter of neozooecia 0.03–0.27 mm, com monly 0.05–0.10 col o nies form mesozooecia (or ? mesozooecia-like structures), mm. Di a phragms in neozooecia usuall y absent , but local ly very flat, fre quently with concen tri c wrinkles . Col ony surface thin hor i zon tal di a phragms, moniliformly curved of smooth or with el evate d maculae. Zooecial openings rounded neozooecial walls, are devel oped (Fig. 7h, j). Dis tance be tween or slightly rounded-polygonal, alway s in contac t with each dia phragm s 0.03–0.10 mm. Local ly in the corners of the inter - other; di am eter of openings be tween maculae 0.25–0.40 mm, sec tions of the zooecia and mesozooecia walls rare, very small on aver age 0.30–0.32 mm. Zooecial di am e ter in maculae (0.01–0.02 mm) poly morphic style-like structure s are devel - 0.4–0.5 mm, on aver age 0.45 mm. In intermacular spaces 5–6 oped, but in most speci m ens these are absent . openings per 2 mm, in maculae about 4. Zooecial walls thin as Oc cur rence. — Widespread spe cies in endo- and exozone. Dia phragm s in some zooecial chambers (or Llanvirn-Caradoc, Uhaku-Kejla regional stages of the East their parts) al most com pletely absent , in others are num erous. Eu ro pean Plat form. Mid dle Or do vi cian, Yugor Re gional Stage Usually dia phragm s straight or slightly curved (rare of North Ural (Paj-Khoj). In the Podlasie-Brest De pres sion cystiphragm-like), mean distanc e betwe en them 0.3–0.8 mm. founded in the follow ing (Dolbnev-Vidomlya for ma tions) Locally at periph eral parts of col onies dia phragm s strongly bore holes: Kustinskaya 1-op, depth 907.5–914.3 m (6 spec i- curved and very frequent; in this case distanc e betwe en dia - mens); Vysokoe 1, depth 843.5 m (1); Novoselki 29, depth phragms is 0.1–0.4 mm. Mesozooecia quite num erous (but 896.1–921.0 m (11); Pribugskaya 17, depth 812.4–829.0 m (4). never isolat ed from zooecial openings), with tri angu - lar-quadrangular openings, diam eter 0.07–0.23 mm. Dia - phragms in mesozooecial cham bers com mon, straight, sepa - rated by 0.10–0.15 mm. Styles small, short, with thin walls, de- Fam ily Mesotrypidae Astrova, 1965 veloped only at colony surface s; di am eter styles about Ge nus Mesotrypa Ulrich, 1893 0.02–0.03 mm. Mesotrypa bystrowi Modzalevskaya, 1953 Re marks. — Modzalevskaya (1953) descri bed (Fig. 8a–h) from the Llanvirn-Caradoc regional stages (CI –DII) 7 species and sub spe cies of Mesotrypa from the Bal tic-Ladoga Glint (Lenin grad region of Russia and Es tonia) . All specie s described have mas sive (gen er ally hemi spher i cal) col o nies and 1829 Orbitulites hemisphaericus Eichwald, p. 179. 1856 Chaetetes (Orbitulites) hemisphaericus Eichwald, p. 91. are num erous in these rocks. Myannil (1959a, b; 1961) pro- 1860 Chaetetes hemisphaericus (pars) Eichwald, p. 476. posed that M. excentrica, M. bystrowi, M. bystrowi 1861 Chaetetes hemisphaericus Eichwald, p. 112.

Fig. 8. a–h — Mesotrypa bystrowi Modzalevskaya, 1953: a–c — BelNIGRI, 12/5-50, Llanvirn, Uhaku Re gional Stage, Lesovchitsy For ma tion, Belarus, Brest re gion, Zhabinka 3 borehole, depth 583 m; a, b — tan gen tial sec tions show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; a — intermacular ar range ment; b — maculae; c — lon gi tu di nal sec tion show ing gen eral ar range ment of zooecial and mesozooecial cham bers, x 10; d, e — BelNIGRI, 12/11-219, Llanvirn, Uhaku Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Lesovchitsy 25 borehole, depth 815 m; d — tan - gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; e — lon gi tu di nal sec tion, x 20; f — BelNIGRI, 12/59-36, Caradoc, Jykhvi Re gional Stage, Vidomlya Form ation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 814 m, tangen tial section, x 40; g — BelNIGRI, 12/1-130, Llanvirn, Uhaku Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Kustinskaya 1-op bore hole, depth 907.5 m, tan gential sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; h — BelNIGRI, 12/59-43, Caradoc, Kejla Re gional Stage, Lystchitsy Form ation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 809.9 m, tan gential section show ing genera l ar range ment of zooecial and mesozooecial openings, x 40. i–l — Mesotrypa excentrica Modzalevskaya, 1953: i, j — BelNIGRI, 12/1-91, Llanvirn, Uhaku Re gional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Kustinskaya 1-op bore hole, depth 911.2 m; i — tan gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; j — lon gi tu di nal sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 20; k — BelNIGRI, 12/1-93, loca tion and age the same, longi tu di nal section, x 6.2; l — BelNIGRI, 12/1-157, Mid dle Or do vi cian, Rus sia, Le nin grad re gion, Popovo (col lec - tion of E. Eichwald, No. 1/157), colo nies, latera l view, nat u ral size Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 429 430 Victor Pushkin tuberculata and M. piriformis (Myannil, 1959b, p. 264–271) 953.2 m (1); Lesovchitsy 25, depth 801.2–815.0 m (17); can all be con sid ered as Mesotrypa excentrica Deshevichi 27, depth 635.1–642.2 m (16); Orlya 28, depth Modzalevskaya, 1953 (ac cording to the rule of “page prior - 1100.5 m (1). ity”). This name (Mesotrypa excentrica Modzalevskaya, 1953) has been used in num erous publi cati ons (Myannil, 1959 a, b, 1961; Pushkin, 1973, 1975, 1976, 1977, 1978, Mesotrypa excentrica Modzalevskaya, 1953 1981, 1986, 1987a, b, c, 2001 and others). Our exam ina ti on of (Figs. 8i–l and 9a–c) a large col lec tion of tan gen tial and lon gi tu di nal sec tions of Mesotrypa from Regional stages CI–DII of the East Euro pean Platform has shown that two differ ent, but re lated spe cies (M. 1829 Chaetetes pyriformis Eichwald, p. 181, pl. 2, fig. 2 (non fig. 1). bystrowi Modzalevskaya, 1953 and M. excentrica 1860 Chaetetes pyriformis Eichwald, p. 478. Modzalevs kaya, 1953) are pres ent in these depos it s, but M. 1861 Chaetetes pyriformis Eichwald, p. 112. 1877 Callopora piriformis Dybowski, s. 117, pl. IV, figs. 6, 6b. bystrowi (non M. excentrica) pre dom i nates. Pres ent ob ser va - 1911 Callopora piriformis Bassler, 1911, p. 343, pl. V, figs. 6, 6b. tions thus agree with Modzalevskaya’s data (Modzalevskaya, 1953 Mesotrypa excentrica Modzalevskaya, p. 112, pl. IV, figs. 1, 2; text-fig. 1953, p.112–115). Pre sum ably M. bystrowi was con sid er ably 4. 1953 Mesotrypa piriformis Modzalevskaya, p. 118, pl. II, figs. 5, 6; text-fig. 7. more widesprea d in the Re gional Stages CI–DII in the East Eu - ro pean Plat form then M. excentrica (by an order of magni - Holotype: No. 731, Depart ment of Pa le on tol ogy, Geo log i cal Fac ulty of the Uni ver sity of St. Pe ters burg, Es to nia, Aluvere quarry, Caradoc, Idavere tude). Mesotrypa bystrowi Modzalevskaya, 1953 differs from Re gional Stage. M. excentrica Modzalevskaya, 1953 in having mainly rounded zooecial openings in contac t with each other (M. Di ag no sis: Mesotrypa with hemi spher i cal or nod u lar col o nies; zooecial openings polyg o nal or rounded-polygonal, frequently sepa rat ed by a excentrica has mainly poly go nal zooecial openings, which row of mesozooecia; di a phragms in zooecial cham bers ir reg u larly de vel oped; are fre quently sepa rated from each other by mesozooecia). In mesozooecia nu mer ous, with po lyg o nal (4–5-cornered) open ings; styles ad di tion, M. bystrowi is char ac ter ised by orig i nally tri an gu lar small, short, devel oped only at col ony sur faces. or qua dran gu lar mesozooecial openings while M. excentrica De scrip tion. — Col onies mas sive, hemi spher i cal has poly go nal (four- or five sided) mesozooecial openings. or depress ed (pastiliform), lo cally nod u lar (Dybowski, 1877, pl. Our ex am i na tion of Early Pa leo zoic bryozoa from Eichwald’s IV, fig. 6; Bassler, 1911, pl. V, fig. 6). Surface of col onies col lec tion (i.e. Pushkin and Gataulina, 1992) has shown that smooth. Zooecial open ings po lyg o nal or rounded-polygonal, Orbitulites hemisphaericus Eichwald, 1829 from Pulkovo frequentl y sepa rat ed by a row of mesozooecia. Zooecial di am e- (see syn on ymy) is the spe cies Mesotrypa bystrowi ter 0.30–0.45 mm; maculae not observe d. Approx i m ately 5 Modzalevskaya, 1953. The restudy also assigne d the specie s zooecial openings per 2 mm. Zooecial walls thin, straight or Mesotrypa pyriformis (Eichwald, 1829) (Modzalevskaya er - slightly curved in endo- and exozone. Di a phragms ir reg u larly rone ously named this specie s as Mesotrypa piriformis de vel oped: in some zooecial cham bers (or their parts) al most (Eichwald, 1853)) to M. excentrica (see be low). com pletely ab sent, in oth ers nu mer ous. Di a phragms usu ally hor- Oc cur rence. — Llanvirn-Caradoc, Azeri-Kejla izon tal or oblique (but not cystiphragm-like), mean dis tance be - regional stages (CIa–DII) of the East Euro pean Plat form. Ex- tween them 0.2–0.6 mm. Mesozooecia abun dant with po lyg o nal cep tionally wide spread spe cies (Modzalevskaya,1953; open ings, com monly qua dran gu lar-pentagonal in out line, di am - Pushkin, 1973, 1975, 1978, 1981, 1986, 2001). In the eter 0.08–0.17 mm. Dia phragm s straight, abundant, distanc e be- Podlasie-Brest Depres sion found (Dolbnev-Lystchitsy for - tween them 0.10–0.17 mm. Styles small, short, devel oped only mati ons) in the fol lowing bore holes: Kustinskaya 1-op, depth at colony surface s. Di am eter of styles 0.015–0.025 mm. 907.5–915.2 m (96 spec im ens); Turna 5, depth 743.5–747.0 Re marks. — A com par i son with M. bystrowi m (5), Zhabinka 3, depth 583 m (2); Ratajchitsy 12, depth Modzalevskaya, 1953, is given in the de scripti on of that spe cies. 956–968 m (2); Vysokoe 1, depth 820.0–836.9 m (5); Our re study of Early Palaeozoic bryozoa from Eichwald’s col lec- Morozovichi 16, depth 890.5 m (1); Borstchovo 10, depth tion has shown that specie s Chaetetes pyriformis Eichwald, 1829

Fig. 9. a–c — Mesotrypa excentrica Modzalevskaya, 1953: a — BelNIGRI, 12/13-62a, Caradoc, Kejla Re gional Stage, Vidomlya For mation, Belarus, Brest re gion, Novoselki 29 borehole, depth 903.2 m, tangen tial section show ing polyg o nal zooecial and mesozooecial openings, x 40; b — BelNIGRI, 12/13-129, Llanvirn, Uhaku Regional Stage, Lesovchitsy Form ation, Novoselki 29 borehole, depth 920.5 m, longi tu di nal section show ing genera l ar - range ment of zooecial and mesozooecial cham bers and the cavi ties (3) of a commensal worm, x 10; c — BelNIGRI, 12/10-10, Llanvirn, Uhaku Regional Stage, Lesovchitsy Form ation, Belarus, Brest re gion, Deshevichi 27 borehole , depth 635.5 m, tangen tial section show ing genera l ar range ment of zooecial and mesozooecial (po lyg o nal) open ings, x 40. d–g — Mesotrypa mesoporica (Pushkin, 1976): d, e — BelNIGRI, 12/13-227, Caradoc, Idavere Regional Stage, Vidomlya Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 906.4 m; d — tan gen tial sec tion show ing gen eral ar range ment of zooecial and mesozooecial openings, x 40; e — lon gi tu di nal sec tion, x 15; f — BelNIGRI, 12/59-8, Llanvirn, Kukruse Re gional Stage, Lesovchitsy For - mation, Belarus, Brest re gion, Pribugskaya 17 borehole, depth 825 m, tangen tial section show ing genera l ar range ment of zooecial and mesozooecial openings, x 40; g — BelNIGRI, 12/8-55, Llanvirn, Azeri-Lasnamyagi region al stages, Dolbnev Form ation, Belarus, Brest re gion, Vysokoe 1 borehole, depth 843 m, the same, x 40. h–l — Mesotrypa gutta Pushkin, 1987: h–j — BelNIGRI, 12/13-273, Caradoc, Kejla Re gional Stage, Lystchitsy Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 893.5 m; h, i — tangen tial sections, x 64; j — lon gi tu di nal sec tion, x 40; k — BelNIGRI, 12/13-258, Caradoc, Jykhvi Re gional Stage, Vidomlya Form ation, Belarus, Brest re gion, Novoselki 29 borehole, depth 901 m, tan gential section show ing genera l ar - range ment of zooecial and mesozooecial openings, x 40; l — BelNIGRI, 12/13-62; Caradoc, Jykhvi Re gional Stage, Vidomlya For ma tion, Belarus, Brest re gion, Novoselki 29 borehole , depth 903.2 m, tan gential section show ing genera l ar range ment of zooecial and mesozooecial openings, x 40 Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 431 432 Victor Pushkin

(spec im ens 1/157; 1/163 from Eichwald’s col lec tion) from tions of the zooecial and mesozooecial walls. 6–12 styles Pulkovo belongs to the specie s Mesotrypa excentrica around each zooecial opening. Modzalevskaya, 1953. Later this form (pyriformis non piriformis) Re marks. — Mesotrypa mesoporica (Pushkin, 1976) was redescribed by Eichwald (1860, 1861), Dybowski (1877), differs from all known specie s of Mesotrypa by the very nu- Bassler (1911) and Modzalevskaya (1953) (see synon ym y). mer ous mesozooecia, formed be tween zooecia 1–2 rows and Oc cur rence. — Llanvirn-Caradoc, Azeri-Kejla re- very small, nu mer ous, in dis tinct styles. gional stages (CIa–DII) of the East Euro pean Plat form. Widely Oc cur rence. — Llanvirn-Caradoc, Lasna - ranging spe cies. In the Podlasie-Brest Depres sion found in the myagi-Idavere re gional stages of Belarus (Podlasie- Brest De- Dolbnev-Lystchitsy form ati ons in the fol lowing bore holes: press ion, Dolbnev-Vidomlya form ati ons) and Lithu a nia . Bore - Ratajchitsy 12, depth 958 m (1 spec im en); Turna 5, depth holes: Kustinskaya 1-op, depth 909.9–913.2 m (5 spec im ens); 740–746 m (2); Deshevichi 27, depth 635.5 m (1); Pribugskaya Brest 9, depth 745 m (1); Vysokoe 1, depth 831–843 m (2); 13, depth 730.2–732.6 m (3); Orlya 28, depth 1091.5–1101.0 Borstchovo 10, depth 942.5–945.0 m (2); Lesovchitsy 25, m (6); Kustinskaya 1op., depth 911.2 m (3); Novoselki 29, depth 813 m (1); Novoselki 29, depth 904–913 m (8); depth 903.2 m (1). In addi ti on this specie s was found in the Pribugskaya 17, depth 819.4–825.0 m (3); Ilgaji 54, depth Vitebsk re gion of Belarus, Lithu a nia, Lat via and Russia in 412.5 m (1); Kibartaji 14, depth 1236 m (1). boreholes and outcrops: Vidzy, depth 326.0–340.7 m (4); Vangishki 205, depth 434.3–449.1 m (3); Ilgaji 54, depth 414.0 m (6); Tauchenis 49, depth 434.9–440.0 m (3); Vilkavishkis Mesotrypa gutta Pushkin, 1987 129, depth 949–960.7 m (15); Vishki 25, depth 546.5–579.5 m (Fig. 8h–l) (8); Ludza 15, depth 600–611.5 m (4); Serebryaniki, depth 1091–1096 m (25); Popovo (1). 1987a Mesotrypa gutta Pushkin, p. 155, pl. IX, fig. 4; pl. X, fig. 1. Holotype: No. 12/13-273, BelNIGRI, Belarus, Brest re gion, Mesotrypa mesoporica (Pushkin, 1976) Novoselki 29 borehole, depth 893.5 m, Caradoc, Kejla Re gional Stage, (Fig. 9d–g) Lystchitsy Form ation. Di ag no sis: Mesotrypa with small, nodu lar , sometim es hollow col o - nies; zooecial openings rounded or oval, contact ing with each other; dia - phragms in zooecial cham bers usu ally ab sent; mesozooecia quite num erous, 1976 Diplotrypa mesoporica Pushkin, p. 28, pl. X, fig. 3. small, po lygo nal in outline; styles very small, in dis tinct, 1–5 styles around Holotype: No. 12/8-55, BelNIGRI, Belarus, Brest re gion, Vysokoe 1 each zooecial opening. borehole, depth 843 m, Llanvirn, Azeri-Lasnamyagi regional stages, Dolbnev For ma tion. De scrip tion. — Col onies small, nod u lar, di am e- ter 1–5 mm, local ly hollow. Zooecial openings rounded or Di ag no sis: Mesotrypa with lamellar or hemi spher i cal col o nies; zooecial openings rounded-polygonal, usually isolate d from each other by oval, zooecial walls always in con tact with each other, di am eter mesozooecia; maculae ab sent from larger zooecia; di a phragms in zooecial 0.17–0.34 mm. Maculae not observe d. Approx i m ately 8 cham bers ir reg u larly de vel oped; mesozooecia very num erous, form 1–2 rows zooecial openings per 2 mm. Zooecial walls straight, thin be tween zooecia; styles very small, indis tinct , num erous: 6–12 styles about each zooecial opening. (thickness 0.010–0.015 mm). Dia phragm s in zooecial chambers usuall y ab sent or single, straight or curved. Mesozooecia De scrip tion. — Col onies lamellar or hemisph er i - quite nu mer ous but zooecial openings not isolat ed. Usually 2–4 cal, rarely nod u lar. Bases of col o nies with basal epitheca. Di- mesozooecia per each zooecia. Di am e ter of po lyg o nal am eter of large hemispher i cal colo nies 18–22 mm, height to mesozooecial openings 0.03–0.13 mm. Dia phragm s in 6–14 mm. Thickness of lamellar col onies 0.6–5.0 mm. Surface mesozooecial chambers straight, distance be tween them of col o nies smooth. Zooecial openings rounded-polygonal 0.03–0.1 mm. Walls of mesozooecia straight (not moniliform). usuall y isolat ed from each other by mesozooecia. Di am e ter of Styles very small (0.01 mm), indis ti nct, devel oped only around openings 0.21–0.38 mm. Maculae com prising of larger zooecia colo nial surface . 1–5 styles around each zooecial opening. ab sent, but small ac cu mu la tions of mesozooecia are oc casion - Re marks. — Mesotrypa gutta Pushkin, 1987 differs ally observe d. These ac cum ula ti ons (size 0.4–0.6 mm) are sur- from M. strumaeformis Pushkin, 1987 from the Oandu and rounded by smaller (!) then usual zooecial open ings (di am e ter Rakvere regional stages of the Balti c Province in having 0.14–0.20 mm). Usually 4.5–5.5 zooecial openings per 2 mm. smaller zooecial openings (per 2 mm 8 against 5–6 openings in Zooecial walls straight, lo cally slightly waved or curved, thick - M. strumaeformis) and in the absenc e of moniliform walls of ness in all parts of col onies 0.015–0.025 mm. Dia phragm s ir- mesozooecia. reg u larly de vel oped: in some zooecial chambers al most com- Oc cur rence. — Caradoc, Idavere-Kejla regional pletely absent , in others, the dis tance betwe en dia phragm s is stages of Belarus (Podlasie-Brest De pres sion, 0.08–0.80 mm. Mesozooecia very num erous, al ways com - Lystchitsy-Vidomlya form ati ons) and Latvia. Bore holes: pletely (or al most completely) sep arated from zooecial open- Novoselki 29, depth 893.5–903.2 m (7 spec im ens); ings. Di a phragms in mesozooecial cham bers nu mer ous, hor i- Pribugskaya 13, depth 844.7–847.5 m (3); Vangishki 205, zontal , dis tance betwe en them 0.03–0.14 mm. Styles very small depth 430.3–439.8 m (3); Ludza 15, depth 597.5 m (2). (0.005–0.015 mm), num erous, indis ti nct, placed at inter sec - Middle Ordovician bryozoa from the Podlasie-Brest Depression (Belarussian part)... 433

BIOGEOGRAPHY CONCLUSIONS

The result s of these bryozoa in ves ti ga tions in the Belarus 1. This is the first monographi c study of the Ordo vi cia n part of the Podlasie-Brest De pres sion sup port the hy poth e sis bryozoa of the orders Cystoporida and Trepostomida from the that during the Llanvirn and Caradoc this area repre sented an Belorussian part of the Podlasie-Brest De pres sion. inde pend ent biogeographical region of the western part of the 2. 23 bryozoa spe cies (4 new spe cies, one new family) are Bal tic Pro vinces (= the Baltic Basin). The de posit s of this descri bed from the Belarussian part of the Podlasie-Brest De- biogeographical region are consid ered as an inde pend ent press ion. Brest-Volyn confacies (Pushkin, 1998, p. 50). In the west 3. On the whole the taxo nomic compo siti on of the bryozoa (Po land) this confacies grades into the Central- Bal tic and studied is simi lar to that of the Bal tic-Ladoga Glint and other Skanian confacies (Modliński, 1973; Jaanusson, 1976; parts of the Bal tic Prov inces, but it is char acter ised by sev eral Modliński and Szymański, 2001), which is consid ered as pe cu liar en demic “Podlasie-Brest” el e ments. deeper-wa ter. In the Brest-Volyn confacies a shal low-wa ter benthos (bryo zoans, brachi o pods, cri noids, mol lusks, some- Ac knowl edge ments. I am grateful to Dr. Caroline Buttler of times trilobites) is pre domi nan t, while in the Cen tral-Bal tic the Nati onal Museum of Wales (United Kingdom ) and Dr. confacies trilobites and graptolites are much more impor tant . Urszula Hara of the Polish Geolog i cal Insti tut e (Poland) for their The tax o nomic com po si tion of bryozoa from Brest-Volyn criti cal and construc tive com ments on the manuscri pt. I wish to confacies dif fers from the “classic” Baltic one by the presence thank Dr. Zdzisław Modliński (Pol ish Geo log i cal In sti tute), of rel a tively nu mer ous en demic “Podlasie-Brest” el e ments Larisa Kozmyan and Svetlana Rozhanskaya (BelNIGRI) for (see “Intro duc ti on” in this paper). their help in the prepa ra ti on of this manuscri pt for publi ca ti on.

REFERENCES

ASTROVA G. (1965) — The morphol ogy , history of devel op ment and sys- FRITZ M. (1941) — Baltic Ordo vician fauna in Gaspe. J. Paleont., 15: tem at ics of Or do vi cian and Si lu rian bryozoa (in Russian) . Trudy 564. Paleont. Inst. Akad. Nauk SSSR. JAANUSSON V. (1976) — Faunal dynam ics in the middle Ordo vician of ASTROVA G. (1978) — The history of devel op ment, systema and phylog - Balto-Scandia. In: The Or dovi cian Sytstem: Pro ceedings of a eny of Bryozoa. Or der Trepostomida (in Russian) . Trudy Paleont. Inst. Palaeont. Ass. Symp. Bir mingham , 1974: 301–326. Cardif f. Akad. Nauk SSSR, 169. JACKSON P. N. W., BUTTLER C. J. and KEY M. M. (2001) — Dianulites BASSLER R. (1906) — A study of the James types of Or dovi cian and Silu - petropolitana Dybowski, 1877 and Diplotrypa petropolitana Nichol - rian Bryozoa. U.S. Nat. Mus. Proc., 30 (1442). son, 1879 (Bryozoa): proposed conser va tion of the specific names. BASSLER R. (1911) — The Early Paleo zoic Bryozoa of the Bal tic Prov - Bull. Zoolog. No men cla ture, 58 (3): 215–219. inces. Bull. Smith so nian Inst., U.S. Nat. Mus., 77. JAMES U. (1875) — Cata logue of Lower Silu ria n fossils at Cincinnati, BEKKER H. (1921) — The Kuckers Stage of the Or dovi cian Rocks of NE Ohio, and vicin ity , with descri p tions of some new species of Corals Es to nia. Acta Com ment. Univ. Dorpatensis, A.2.1. and Polyzoa: 1–8. Cincinnati. BORK B. and PERRY T. (1967) — Bryozoa (Ectoprocta) of Champlainian KARKLINS O. (1984) — Trepostome and cystoporate bryo zoans from the age (Mid dle Or do vi cian) from north west ern Il li nois and ad ja cent parts Lexington Limestone and Clays Ferry Form ations (Middle and Up per of Iowa and Wiscon sin. Part 1. Amplexopora, Monotrypella, Or do vi cian) of Ken tucky. Geol. Surv. Pro fess. Pa per, N 1066-1 (6). Hallopora and Batostoma. J. Paleont., 41 (6): 1365–1392. McKINNEY F. (1971) — Trepostomatous Ectoprocta (Bryozoa) from the CUMINGS E. (1908) — The Stratig ra phy and pale on tology of the Lower Chicamauga Group (Mid dle Or do vi cian), Wills Val ley, Ala - Cincinnati Serie s of Indi ana. Indi ana Dep. Geol. Nat. Res., 32nd Ann. bama. Bull. Amer. Paleont., 60 (267): 195-337. Re port: 605–1189. MODLIŃSKI Z. (1973) — Stra tig ra phy and de vel op ment of Or do vi cian DYBOWSKI W. (1877) — Die Chaetetiden der Ostbaltischen in north eastern Po land (in Polish with English summ ary). Pr. Inst. Silur-Formation. Verhandlungen der Russisch-Keiserlichen Min eral. Geol., 72. Gesellshaft zu St. Pe ters burg, 2 (14). MODLIŃSKI Z. and SZYMAŃSKI B. (2001) — Stra tig ra phy and li thol - EICHWALD E. (1829) — Zoologia Specialis quam expositis animalibus ogy of Ordovician in the Suwałki Area (north eastern Po land) (in Pol- tum vivis tum fossilibus potissimum Russiae in universum et Poloniae ish with Eng lish summ ary). Biul. Państw. Inst. Geol., 394: 55–72. in spe cie, Vilnae (Bryozoa) 1:179–180; 198–201. MODZALEVSKAYA E. (1953) — Trepostomaty ordovika Pribaltiki i ikh EICHWALD E. (1856) — Beitrag zur geographischen Verbreitung der stratigraphicheskoe znachenie (in Rus sian). Trudy Vsesoyuznogo fossilen Thiere Russlands. Bull. Soc. Imper. Natur. Moscou Neftyanogo Nauchno-Issledovatel’skogo Geologorazvedochnogo (Bryozoa), 29: 91–96. Instituta (VNIGRI), 78: 91–167. EICHWALD E. (1860) — Lethaea Rossica, ou Paleontologie de la Russie. MYANNIL R. (1959a) — Voprosy stratigrafii i mshanki ordovika Estonii 1 — Ancienne Pe riod. Stuttgard. (in Russian). Avtoreferat kandidatskoj dissertatsii. Tallin. EICHWALD E. (1861) — Paleontologiya of Rossii. Drevnij period. 2 — MYANNIL R. (1959b) — Voprosy stratigrafii i mshanki ordovika Estonii Fauna grauwakkovoj, gornoizvestkovoj i medistoslanzevoj formatsij (in Russian). Dissertatsiya na soiskanie uchenoj stepeni kandidata Rossii (in Russian). geologo-mineralogicheskikh nauk. Tallin. FOORD A. (1883) — On the Monticuliporidae of the Chazy, Black River, MYANNIL R. (1961) — K morphologii polusfericheskikh mshanok and Trenton form ations, with descri p tions of ten new species . Contri - otryada Trepostomata (in Russian with Eng lish summ ary). Eesti NSV bu tions to the Micro- Palaeontology of the Cambro-Silurian Rocks of Teaduste Akad. Geol. Inst., Uurimuse, 6: 113–140. Can ada. Part 1. Geol. Natur. His tory Surv. Can ada. 434 Victor Pushkin

NEKHOROSHEVA L. (1970) — Ordovikskie mshanki severa Paj-Khoya, PUSHKIN V. (1987b) — Ordovikskie mshanki Vostochno-Evropejskoj Vajgacha i yuga Novoj Zemli (in Rus sian). Trudy NIIGA. Opornyj platformy (sostav, rasprostranenie, soobstchestva) (in Russian). razrez ordovika Paj-Khoya, Vajgacha i yuga Novoj Zemli: 63–95. Avtoreferat doktorskoj dissertatsii. Moskva. NICHOLSON H. (1875) — Report upon the Pale on tol ogy of the Province PUSHKIN V. (1987c) — Structura soobstchestv mshanok Baltijskogo of Ontar io-Toronto. Edinburg. bassejna (in Rus sian). Trudy 29 sessii Vsesoyuznogo NICHOLSON H. (1879) — On the struc ture and affinites of the “Tabu late Paleontologicheskogo obstchestva: 45–59. Lenin grad. Corals” of the Pa leo zoic pe riod with crit i cal de scrip tions of il lus tra tive PUSHKIN V. (1990) — Mshanki semejstva Ceramoporidae iz ordovika spe cies: 253–327. Edinburg. Vostochno-Evropejskoj platformy. Novye predstaviteli iskopaemoj NICHOLSON H. (1881) — On the structure and af fin i ties of the ge nus fauny i flory Belorusi i drugikh rajonov SSSR (in Rus sian): 5–34. Monticulipora and its sub-genera with crit ical de scrip tions of illus tra- Minsk. tive spe cies. Edinburg. PUSHKIN V. (2001) — Ordovikskaya sistema (in Russian). Geologiya PANDER C. (1830) — Beitrage zur Geognosie des Russischen Reiches. Belarusi (eds. A. S. Makhnach, R. G. Garetskij, A. V. Matveev et al.): Pe ters burg. 157–171. Minsk. PUSHKIN V. (1973) — Biostratigrafiya i mshanki ordovika i silura PUSHKIN V. and GATAULINA G. (1992) — A revi sion of Early Paleo - Brestskoj vpadiny (in Russian). Avtoreferat dissertatsii na soiskanie zoic Bryozoa of the order Cystoporida from Eichwald’s collec tion (in uchenoj stepeni kandidata geologo-mineralogicheskikh nauk. Rus sian). Voprosy Paleont., 10: 88–97. Moskva. PUSHKIN V. and MODLIŃSKI Z. (2002) — Llanvirnian and Caradocian PUSHKIN V. (1975) — Kompleksy mshanok iz otlozhenij ordovika i brachi o pod and bryozoa as so ci a tions of the Podlasie-Brest Depres - silura Brestskoj vpadiny i ikh paleogeograficheskoe znachenie (in sion. Tezisy dokladov V Bal tic Strati graphi cal Con fer ence. Rus sian). Voprosy geologii, geokhimii i geofiziki zemnoj kory PUSHKIN V. and POPOV L. (2001) — Rod Dianulites (Bryozoa, Belorussii: 155–161. Minsk. Trepostomida) v arenige i llanvirne Vostochno-Evropejskoj platformy PUSHKIN V. (1976) — Novye vidy ordovikskikh i silurijskikh mshanok (in Rus sian). Litasphera: 12–32. Brestskoj vpadiny (in Russian). Novye vidy iskopaemykh zhivotnykh ROEMER C. (1861) — Die fossile Fauna der Silurischer i rastenij Belorusi: 3–40. Minsk. Diluvial-Geschiebe Nieder-Schlesien: 1–81. Breslau. PUSHKIN V. (1977a) — O sistematicheskom polozhenii i sostave roda ROPOT V. and PUSHKIN V. (1987) — Ordovik Belorussii (in Russian) Dittopora (Bryozoa) (in Rus sian). Zhizn’ Zemli. Trudy Muzeya (ed. A. S. Makhnach). Nauka i Tekhnika. Minsk. zemlevedeniya MGU. Vypusk, 12: 97–113. Moskva. ROSS J. (1969) — Champlainian (Or do vi cian) Ectoprocta (Bryozoa), PUSHKIN V. (1977b) — Novyj rod ordovikskikh mshanok (in Russian). New York State. Part 2. J. Paleont., 43 (2): 257–284. Paleont. Zhurn., 4: 67–72. ROSS J. (1970) — Distri bu tion, Paleoecology and Cor re la tion of PUSHKIN V. (1978) — Biostratigraficheskaya kharacteristika ordovika v Champlainian Ectoprocta (Bryozoa), New York State. Part 3. J. razreze skv. Vidzy (Vitebskaya obl. BSSR) (in Russian) . Sovremen. Paleont., 44 (2): 346–382. probl. geol. BSSR: 15–22. Minsk. ULRICH E. (1882) — Ameri can Pa leo zoic Bryozoa. J. Cincinnati Soc. PUSHKIN V. (1981) — Stratigrafiya i korreljatsiya Natur. His tory, 5: 121–175; 232–257. nizhne-sredreordovikskikh otlozhenij Belorusi (in Russian). ULRICH E. (1893) — On Lower Silu ria n Bryozoa of Min nesota. Minne - Geologiya zapada Vostochno-Evropejskoj platformy (ed. R. G. sota Geol. Natur. His tory Surv. Min ne ap o lis, 3 (1): 96–332. Garetskij): 73–91. Minsk. UTGAARD J. (1968) — A revi sion of North Ameri can genera of PUSHKIN V. (1986) — Soobstchestva bryozoan and brachio pods in ceramoporoid bryozoans (Ectoprocta). 1 — Anolotichiidae. J. nizhne-sredneordovikskikh otlozheniyakh Yuzhnoj Pribaltiki (in Rus - Paleont., 42 (4): 1033–1041. sian). Paleontologija i ee rol’ v poznanii geologicheskogo stroeniya UTGAARD J. (1969) — A revi sion of North Ameri can genera of territorii Belorusi: 33–63. Minsk. ceramoporoid bryozoans. (Ectoprocta). 3 — the ceramoporoid genera PUSHKIN V. (1987a) — Ordovikskie mshanki podotryada Halloporina Ceramopora, Papillalunaria, Favositella and Haplotrypa. J. Paleont., Belorussii i smezhnykh rajonov Vostochno-Evropejskoj platformy (in 43 (2): 289–297. Rus sian). Ordovik Belorusi (ed. A. S. Makhnach). Nauka i Tekhnika: 145–197. Minsk.