Papiliograptus retimarginatus Lenz & Kozlowska-Dawidziuk 2002, n. sp.

Papiliograptus retimarginatus n. sp. (Figs 1; 2A, C, D; 3) urn:lsid:zoobank.org:pub: 6FCD1C79-A0BC-4C6A-97F2-5727E5FFECD7 Retiolites (Plectograptus) retimarginatus – Jaeger (nomen nudum). — Maletz 2010: 503, fig. 1 (no description). Papiliograptus retimarginatus – Maletz 2010: 505, fig. 2 (no description). Papiliograptus papilio – Kozłowska & Radzevičius 2013: 14-15, figs 3, 4. — Kozłowska 2016: 539, fig. 4A. Papiliograptus sp. — Maletz et al. 2017: 218, fig. 12.9D. HOLOTYPE. — ZPAL G.62/1 is from depth 1647.9 m, Bartoszyce IG-1 core, Poland. DIAGNOSIS. — Papiliograptus with single genicular structure formed as long lateral lists, thinning distally and lacking a ventrally continuous (connecting) rim; delicate reticulum in the proximal part of the hoods, growing from geniculum and reaching sideways onto the preserved spiny extensions. ETYMOLOGY. — The name of the species retimarginatus is from the Latin: reti means reticulum; marginatus means having a border or margin. It is based on the reticulated margins of the elongated genicular processes of this taxon. The name is retained from the specimen of Hermann Jaeger, who called the taxon Retiolites (Plectograptus) retimarginatus in his notes with no year. LOCUS TYPICUS AND STRATUM TYPICUM. — Bartoszyce IG-1core, north eastern Poland; lower part of the praedeubeli /deubeli Biozone, upper Homerian, Wenlock, Silurian. MATERIAL EXAMINED. — Several specimens from depths 1647.9 m and 1649.0 m, Bartoszyce IG-1core, mostly fragments, two specimens with proximal end. Paratype (ZPAL G.62/3-5) comes from depth 1649.0 m. The material is associated with Gothograptus auriculatus Kozłowska, Bates, Zalasiewicz & Radzevičius, 2019; and Colonograptus praedeubeli Jaeger, 1990. A single juvenile specimen (MBg 1092; JM 59) comes from a glacial boulder, Hiddensee, Rügen Island, northern Germany. C A B DESCRIPTION The holotype is a proximal fragment with about five pairs of thecae. The specimen is preserved on an SEM stub in obverse view and is nearly completely flattened, showing a slightly distorted and rotated lateral preservation with the ventral side of thecal series two shown completely, while the apertural orifices of thecal series one are covered and only the lateral genicular constructions are visible (Figs 1; 2A). The specimen has a maximum length of c. 4.5 mm. The paratype specimen represents the proximal part of a tubarium in which only the first two thecal pairs are preserved and the genicular processes of th11 and 21 are well-developed (Fig. 3). The tubarium widens slightly from the level of the ancora umbrella rim, which is the narrowest part of the colony. The approximate lateral width of the holotype tubarium, measured between the pleural lists below the lip of th11, is 0.7 mm and reaches 1.1 mm at the level of the lip of th32. The 2TRD, two thecae repeat distance (Howe 1983) at th 41 is 1.38 mm. The nema is free inside the tubarium, but appears to be connected to a rounded list, probably representing part of th 61 in the holotype, which may indicate a finite growth of the colony. The length of the sicula cannot be determined from this specimen and has not been recognized in other material. The ancora umbrella is formed from seven meshes and is fairly asymmetrical, as the paired ventro-lateral ancora umbrella lobes reach much higher on the th21 side. The rim of the ancora umbrella is strongly lobate and shows paired lobes on the ventro-lateral sides of both thecal series and two lobes on the lateral sides of the tubarium, which are distinctive in ventral view of well-preserved material, but difficult to see in the flattened type material. The ancora umbrella is moderately deep, reaching a width of c. 0.8 mm on the obverse and reverse sides and a depth of c. 0.65 mm at the ventro-lateral lobes in the holotype, but as the specimen is flattened, this might not be accurate. The single specimen from the Jaeger collection preserved in full relief is about 0.7 mm wide and c. 0.5 mm high. Drawing by Jaeger (Maletz 2010: fig. 1) shows the reverse side of the specimen and highlights the characteristic lateral, nearly vertical lobes of the ancora umbrella. The width across these lateral lobes of the ancora umbrella is 0.55 mm in the Jaeger specimen (Fig. 2D). The shape of the proximal ventral orifice on the theca one series is approximately hexagonal on the holotype (Figs 1; 4). In the Jaeger specimen the proximal ventral orifice of the theca two series is tetragonal. The rounded proximal lateral orifices are located centrally on the lateral sides of the tubarium. They may appear as of kidney shape when the colony is flattened and the lateral lobes rotated upwards as in the holotype of the species.However, in the original three-dimensionally preserved material, they show a widely arched rim with a horizontal base. The ancora sleeve is outlined on the ventral (thecal orifice) sides by pleural lists, the lateral apertural rods, genicular lists and thecal lips. The genicular lists are thinner than thecal lips, lateral apertural rods and pleural lists and in more distal thecae it is difficult to distinguish them from the reticulum of the genicular structure. The mid-ventral lists are relatively thin in the available material and appear to be constructed at a later stage of the colony development (Figs 1; 4). Thus, they appear to be incomplete in distal parts of the few available specimens and are difficult to differentiate from other lists on the ventral side of the tubarium. The lateral walls of the ancora sleeve show a distinct dense meshwork of lists, showing an indistinct zigzag pattern of slightly wider main lists, while smaller meshes are aligned in curved rows. The single larger specimen from Lithuania appears to show a more regular zigzag pattern (Kozłowska & Radzevičius 2013; Kozłowska 2016: fig. 4A) in the medial and distal part of tubarium. The cortical bandages show the distinctive, regularly developed pustules on the surface. The thecal orifices have a semi-rectangular shape and increase slightly in size and regularity towards the distal end. They bear paired, long and outwards directed genicular processes with seams on the inside, indicating the former presence of a nonpreserved membrane. The membranes supported a delicate reticulum spreading along the spines and being widest in the centre. The genicular processes of Papiliograptus retimarginatus n. sp. represent some of the largest genicular constructions among retiolitids. The distance between the tips of the lateral lists of the genicular processes is about 1.8-2.0 mm in th12, about 2.5 mm in th22. The genicular processes appear to start as “spiny” extensions from the genicular edges of the thecal orifices and the delicate reticulum developed along the genicular lists as well as these processes which grow out for a considerable distance. Strong, curved bounding lists then appear at the geniculum and spread on the inner side of the lateral genicular “spines” to form a meshwork of fine meshes. At most a maximum of two layers of meshes can be seen along the genicular processes, but it may be assumed that a much wider membrane was extending between the processes. DISCUSSION OCCURRENCE OF PAPILIOGRAPTUS SPECIES Papiliograptus species appear to be restricted to Laurentia and Baltica, evolving during the post- lundgreni extinction interval, during the recovery phase of graptolite faunas. The type species Papiliograptus papilio Lenz & Kozłowska-Dawidziuk, 2002 is described from the Arctic Canada, Laurentia, from the middle part of the praedeubeli /deubeli Biozone (Lenz & Kozłowska-Dawidziuk 2002). The second species of the genus, Papiliograptus retimarginatus n. sp. is described herein from Poland, East European Platform, Baltica, from the praedeubeli /deubeli Biozone. Kozłowska& Radzevičius(2013) described Papiliograptus papilio from the lower part of the praedeubeli Biozone of the Šiupyliai-69 drill core of Lithuania, based upon a number of fragments and a single mature specimen. This specimen is comparable to Papiliograptus retimarginatus n. sp. in the development of the genicular extensions which have destroyed distal ends.We include this material in Papiliograptus retimarginatus n. sp. because the remnants of the genicular processes show big similarity of the construction to the new species.There are some fragments of the thicker “spiny” extensions and delicate reticulum between them. A single immature specimen known from a North German glacial boulder, referred in manuscript notes to the praedeubeli Biozone by Jaeger, is regarded as Papiliograptus retimarginatus n. sp. However, the characteristic genicular structures are not well-developed and partly destroyed (Fig. 2D). Porębska et al. (2004: fig. 3F) illustrated a single specimen with a proximal end and three pairs of thecae as Papiliograptus papilio (?) from the praedeubeli Biozone of Poland, East European Platform, Baltica. Specimens identified on the range chart as Papiliograptus papilio from the base of the praedeubeli Biozone from Lithuania, East European Platform, Baltica (Radzevičius et al. 2014: fig.2) have not been illustrated. Thus, their identity remains uncertain. GENICULAR STRUCTURES IN PAPILIOGRAPTUS SPECIES Papiliograptus papilio and Papiliograptus retimarginatus n. sp. can be differentiated easily by the shape and size of their respective genicular processes.The genicular hood of Papiliograptus papilio is a two-lobed single hood construction with a rounded rim on the geniculum of the thecae (Fig. 5B). The rim is continuous and composed of a delicate reticulum, not strong bordering lists as in Papiliograptus retimarginatus n. sp. This hood extends horizontally from the ventral wall of the tubarium or bends slightly downwards in the distal end at the rim. A distinct lateral thickening as in the processes of Papiliograptus retimarginatus n. sp. is not developed in Papiliograptus papilio.They are much smaller and only slightly extend beyond the borders o

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