No. 1] Proc. Japan Acad., 61, Ser. B (1985) 5

2. The Taihungshaniidae and Birmanitidae, Trilobita

By Teiichi KoBAYASHI, M. J. A.

(Communicated Jan. 12, 1985)

It was in 1936 that I have pointed out that Miquelina Thoral, 1935 is syn- onymous with Taihungshania Sun, 1931 and Asaphelina Munier-Chalmas and Bergeron, 1889 belongs to the Taihungshaninae in the Asaphidae. Later two more genera, Omeipsis Kobayashi, 1951 and Tungtzuella Sheng, 1957 were added to them and the subfamily was accepted as a distinct family in the Asaphacea in Moore's Treatise of Invertebrate Paleontology (1959). According to Lu (1975) 6 species of Taihungshania, one of Omeipsis and 4 species of Tungtzuella are known :from China. Tungtzuella occurs in lower Arenigian in central and southwest China, Taihungshania in Arenigian and lower Llanvirnian in Hubei, Guizhou and Sichuan and Omeipsis in upper Llanvirnian, Sichuan. Beside these I could find 2 species of Tungtzuella and four of Taihung- shania which were described by Sheng, Yin and Xia from Hubei and Guizhou in Palaeontological Atlases of Southwest China (1977) , Guizhou (1978) and Ichang Gorge Biostratigraphy (1978) . Thus the Chinese species total no less than 10 and 8 for Taihungshania and Tungtzuella respectively. Taihungshania miqueli was reported to occur in China by Chou et al. (1977). As I prevised in 1960 that two lineages may be distinguishable in Taihung- shania, namely, T. shui series having semiparabolic and multisegmented pygidia and T. brevica series having semicircular and paucisegmented pygidia, the inter- specific relationship of these genera must be an interesting subject for future study. According to Courtessole, Pillet and Vizcaino (1981) the Mongtagne Noire forms of Taihungshania are classifiable into T. miqueli (Thoral) and two Thoral's subspecies of T. shui Sun. It is known further that Taihungshania occurs in the Malyi Karatau range in Kazakhstan (Acad. Sci. Kazakhstan, 1984). These three authors distinguished two subspecies, barroisi and bernardi in Asaphelina barroisi Bergeron, 1889, from the Arenigian of Mongtagne Noire, South France. Another species is A. boliviensis Pribyl and Vanek, 1980, from Arenigian in Bolivia. The third species may be Asaphelina (?) magna Tschu- gaeva, 1973, from the late Lower Ordovician in Northeast USSR. Of Asaphelina (?) sp. by Ross (1951) from the Garden City formation, Utah, he states that the pygidial similarity is so striking that their close relation is more than probable. Thus the genus was distributed from the western Mediterranean to the Andes and probably the Cordilleran of North America and on the other side into the Asiatic part of the Soviet Union in the late Lower Ordovician age. In 1940 I have referred Dionide hectori Reed, 1926, from New Zealand to Taihungshania. Recently Lu (1975) proposed Hectoria for it. Its age is known now Tremadocian, instead of Arenigian (Cooper, 1979). In summarizing the existing facts gathered during the past half century it can be concluded at present that Taihungshania is a key to the Arenigian- Llanvirnian from France to China through Kazakhstan. Remarkably enough, T. miqueli is a trans-Eurasiatic Arenigian species. The family, Taihungshaniidae, has flourished most in China where three genera, Tungtzuella, Taihungshania and 6 T. KOBAYASHI [Vol. 61(B),

Omeipsis occur. The next is France whence two genera, Asaphelina and Tai- hungshania are known. Asaphelina indicates the trans-Atlantic branch in the late Lower Ordovician age when it was probably distributed also to Northeast Asia. The oldest genus of the family would be Hectoria. Omeipsis which appeared just before the disappearance of the family had the highly specialized pygidium.

Figs. 1-3. 1 Birmanites birmanicus (Reed). 2 Birmanites (Birmanitella) hupeiensis Yi. 3: Pseudobirmanites leiboensis Lee.

Now Birmanites is to be discussed. B. birmanicus has two pairs of weak lateral furrows on the glabella, anterior ones of which being oblique and the posteriors transversal, and the niobi-form facial sutures. The second species is Birmanites hupehensis Yi, 1957, from the Miaopa formation (upper Llandeilo- lower Caradocian) , Hubei in which the facial suture is isoteli-form and its glabella has the triangular basal lobes. A median tubercle is present in front of the occipital ring, the genal spine long, the median preglabellar fold particularly prominent and the pygidium has interpleural furrows. Therefore I proposed in 1960 a new subgenus, Birmanitella, for the second species. Recently Lu (1975) said that B. birmanicus had a pair of basal lobes as seen in a specimen (Reed, 1915, pl. 5, fig. 18), but the lobes are evidently the secondary products by lateral compression causing a sharp frontal angle of the glabellar outline. The basal lobes are inrecognizable not only in Reed's other specimens including the holotype, but also in Sheng's specimens from Zhejiang, East China. On this occasion Lu added two Middle Ordovician species, B. yangtzensis and B. politus. Since then seven new species were added by Lu, Yin, Lee and Ju through Palaeontological Atlases of Southwest China, Guizhou, Sichuan, Northwest China and East China (1977-83). Arenigian B. sichuanensis bears basal lobes, a median tubercle and long genal spines, but the suture appears niobi-form. Among Zhong's three Middle Ordovician species from Xinjian the basal lobes of the glabella and isoteli-form suture are recognizable in B. kan- iongensis and B. gilangensis. Lower Ashgillian B. dabashanensis Lu from Hubei is represented by a pygidium having double pleural ribs of Birmanitella. B. juxianensis Ju from Zhejiang is another Upper Ordovician species whose glabella has basal lobes, but its facial suture appears niobiform. The associate pygidium with the distinct marginal border of this species may not belong to Birmanites. In looking through various species of Birmanites the basal lobes are more important than the facial sutures for the distinction of Birmanitella from No. 1] Taihungshaniidae, Birmanitidae 7

Birmanites, s. str. This genus is so aberrant for asaphoids that it cannot be referred to the Asaphinae, Ogygiocarinae or any other subfamily of the Asaphidae. To involve it in the family it requires certain important modification of the family-diagnosis with regard of the short glabella, large eyes in posterior and close to glabella, very narrow axial lobe of the thorax and the extraordinary development of the marginal brims of the cephalon and pygidium. The Birmani- tidae is such a distinct family probably of the Asaphacea. Tomkolian Ogyginus aff. cordensis from South Korea and Lower Ordovician Ogygites ( ?) annamensis Mansuy, 1920 are probably referable to Birmanites (Kobayashi, 1950; Lu, 1975) . Middle Ordovician B, almatyensis (Tschugaeva, 1958) from Kazakhstan may be a B. (Birmanitella) . According to Lu Birmanites occurs further in Llanvirnian of Ordos, Inner Mongolia. In short, Birmanites is an important Ordovician genus in Eastern and Central Asia in the range from Tremadocian to early Ashgillian. Finally, sundry taxonomic notes are added. In 1960 I placed provisionally Tropidopyge Harrington and Kay, 1951 and Hagiorites Kobayashi, 1950 both represented by pygidia, in the Birmanitidae. The former is based on Tremadocian Dikelocephalus broggeri Moberg and Segerberg, 1906, and primarily included in the Dikelocephalidae, but later it was transferred into the Hypermesecaspididae in Moore's Treatise (1959) and also by Forty (1974), in describing T. alvrus, nov. with the cranidium. The latter's type species is Hagiorites omeishanensis whose pygidium differs essentially from that of Tropidopyge in the absence of the post-axial ridge. Metatemnoura Sun, 1977 is represented by monotypic M. magna Sun from the Miaopa formation, Hubei which is a large trilobite having a roundly sub- quadrate pygidium protruded behind on the lateral sides of the posterior margin, like T emnoura and Dainellicauda. Although its cephalon is not well known, the forked hypostoma, large posterior eyes, eight thoracic segments and broad brims of the cephalon and pygidium reveal its intimate relationship to Birmanites. Finally, Pseudobirmanites Lee, 1976 is represented by P. leiboensis Lee from the Upper Ordovician (Ashgillian) of Sichuan. In the small micropygous dorsal shield about 1 cm long, three transveral furrows on the relatively short glabella, very small eyes near the middle part of the glabella, linear folds radiat- ing from the glabella, narrow marginal border clearly defined by marginal furrows, absence of genal spines and two straight branches of the facial sutures rec- tangularly divergent from the eyes on the cephalon, much narrower thorax than cephalon, its axial ring subequal to pleuron in breadth, somewhat truncated pleural terminus and small subelliptical pygidium with breviconic axial lobe composed of three rings, paucisegmented pleural lobes and distinct narrow marginal border, this trilobite is so distinct from the Asaphidae and also other families that it required a new family for which Pseudobirmanitidae is here proposed.

References)

Academy Sci. Kazakh SSR (1984) : Trilobites and Condonts from the Batyrbay Section (Uppermost Cambrian-Lower Ordovician) in Malyi Karatau Section (Atlas of Pal. plates). 48 pp.

*' See also Kobayashi (1985) , preceding article. 8 T. KOBAYASHI [Vol. 61(B),

Chou Hong-an et al. (1983) : Trilobita, pp. 28-254. Palaeont. Atlas of East China (1), Early Palaeozoic. 657 pp., 176 pls. Cooper, R. A. (1979) : Lower Palaeozoic rocks of New Zealand. J. Roy. Soc. N. Z., 9(1), 29-84. Forty, R. A. (1974) : The Ordovician trilobites of Spitzbergen. I, Olenidae. Norsk. Polarinst. Skrift, NR. 160, 129 pp., 24 pls. Harrington, H. J., and Kay, M. (1951) : Cambrian and Ordovician faunas of eastern Columbia. J. Pal., 25, 655-668, pls. 96-97. Kobayashi, T. (1940) : On the occurrence of Taihungshania a characteristic Arenigian trilobite in New Zealand. Japan. J. Geol. Geogr., 17, 195-201, pl. 20. (1950) : On Birmanites, a Lower Ordovician genus of trilobite. J. Geol. Soc. Japan, vol. 35, pp. 523-526. (1951) : On the Ordovician trilobites in Central China. J. Fac. Sci. Univ. Tokyo, sec. 2, 8, pt. 1, 1-87, pls. 1-5. Ross, R. J. (1951) : Stratigraphy of the Garden City formation in Northeastern Utah and its trilobite faunas. Peabpdy Mus. Nat. Hist. Yale Univ., Bull. 6, 161 pp., 36 pls. Sheng, S. F. (1934) : Lower Ordovician trilobite fauna of Chekiang. Pal. Sinica, B, 3, fasc. 1, 19 pp., 4 pls. Zhang, Ta-Rong (1981) : Trilobita, pp. 134-213. Palaeont. Atlas of Northwest China, Xinj fang Weiwur Autonomic Province (1). 332 pp., 92 pls.