Bathonian–Callovian (Middle Jurassic) Ammonites from Northwestern

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Proceedings of the Geologists’ Association 127 (2016) 247–265

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Bathonian–Callovian (Middle Jurassic) ammonites from northwestern

Qiangtang Block, Tibet, and the revised age of the Suowa Formation

Jiarun Yin *

China University of Geosciences (Beijing), 29 Xueyuan Lu, Beijing 100083, PR China*Tel.: ++86 1084825070.

A R T I C L E I N F O A B S T R A C T

Article history: The age of the Suowa Formation, the latest Jurassic marine deposit in the Qiangtang Block, is important

Received 22 August 2015

not only because of its great hydrocarbon potential, but also because it deﬁnes the termination of the

Received in revised form 6 February 2016

Jurassic ocean in the area. New ammonite evidence from the upper part of the Suowa Formation in the

Accepted 10 February 2016

northwestern Qiangtang region allows us to revise the age of the formation previously regarded as late

Available online 19 March 2016

Jurassic due to the absence of time-diagnostic fossils. Newly collected ammonites include Gracili-

sphinctes suprapanatinus (Arkell), Oxycerites orbis (Giebel), Macrocephalites (Macrocephalites) madagas-

Keywords:

cariensis Lemoine, Macrocephalites compressus (Quenstedt), Nothocephalites semilaevis (Waagen) [M],

Qiangtang Block (northern Tibet)

Nothocephalites asaphus Spath [m], Eucycloceras cf. cogginbrowni Spath, Choffatia (Subgrossouvria)

Bathonian–Callovian

Ammonite recuperoi (Gemmellaro) and Choffatia cf. sakutala Spath. Correlation with the biostratigraphical

Biostratigraphy framework based on ammonites from Kachchh, western India, places the age of the Suowa Formation as

Suowa Formation Middle Bathonian to Early Middle Callovian. An unconformity and depositional break between the

Suowa Formation and the overlying Lower Cretaceous Xueshan Formation is proposed. Characteristic

ammonite-taxa of Kachchh appearing in the northwestern Qiangtang area document signiﬁcant

dispersal from the Indo-Malgach Province to the northern margin of eastern Tethys region for the ﬁrst

time.

1. Introduction sedimentary environments (Tan et al., 2002, 2003, 2004; Jin et al.,

2006; Zeng et al., 2012a,b).

The Qing-Zang (Qinghai-Xizang) Plateau consists of three The Jurassic lithostratigraphical units of the Yanshiping section

tectonic terrains, from north to south they are the Qiangtang, comprise the Quemocuo, Buqu, Xiali, Suowa, and Xueshan

Lhasa and Himalayan blocks. The Qiangtang Block including formations in ascending order (Yin, 1986; Yang and Yin, 1988;

northern Tibet, parts of southern Qinghai and western Yunnan Bai, 1989). Depositional environments were either tide-dominated

provinces was subjected to continental collision with the southern shelf or inner carbonate shelves throughout Jurassic times, and

margin of the Eurasian continent by the late Triassic and were bivalve fossils are quite diverse and abundant, being represented

separated from the Lhasa Block by the Bangonghu-Nujiang Ocean by marine, brackish-water, and freshwater forms (Yin, 1989a,b,

during the Jurassic (Wang, 1985). The ammonite specimens 1990; Yin and Fu¨ rsich, 1991; Yin et al., 1993). Therefore the

studied here are from northern Tibet (Fig. 1). stratigraphical units above have been dated only by their bivalve

Jurassic strata are well developed and widely distributed in the assemblages, and the Suowa Formation has been regarded as Late

Qiangtang region, an area of approximately 650 km from east to Jurassic in age (Yin, 1986, 1987; Yang and Yin, 1988; Bai, 1989).

west and 300 km from north to south. Different depositional basins This stratigraphical scheme has been applied in both geological

existed in the north and south, separated by an uplift zone around a survey mapping and petroleum oil exploration in the Qiangtang

latitude of 338 N (Fig. 1, right). As a result, different Jurassic region since the early 1990s (Fig. 2).

sedimentary facies developed (Wang et al., 2001, 2004, 2009; Zhao Jurassic ammonite assemblages were not reported from

et al., 2001). The northern Qiangtang region can be subdivided into northern Qiangtang until the 1988, particularly in the area from

the eastern Yanshiping-Cuoriju area and the western Bailong- Yanshiping to Cuoriju where ammonites are extremely rare due to

binghe-Bandaohu (Changhonghe) area based on differences in the very shallow-water facies. The only ammonite previously

known from the area is Collotia sp. (Wang et al., 1979). The ﬁrst

report of Late Jurassic ammonites in the Bailongbinghe section of

E-mail address: [email protected]. northwestern Qiangtang (Fig. 1, right) was made by Fan et al. (1988)

http://dx.doi.org/10.1016/j.pgeola.2016.02.005

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Fig. 1. Tectonic suture zones of the Qinghai-Xizang (Tibet) Plateau (left) and Middle Jurassic ammonite localities known in the Qiangtang Block (right).

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 249

Fig. 2. Middle Jurassic, Upper Jurassic and Lower Cretaceous lithostratigraphical schemes in northern Qiangtang.

and these ammonites were neither ﬁgured or described, but many the Spiti Shale depositional environments, by containing shallow-

taxa were listed, such as Virgatosphinctes sp., V. cf. subfrequens, V. water carbonate platforms, but also because the fossil assemblage

minusculus, V. cf. pompeckji, V. cf. kraffti, V. cf. frequens, Spiticeras, lists have been compiled by researchers inexperienced in the

Paraboliceras, and Perisphinctes. Most of these ammonites are determination of ammonites. It is highly unlikely that so many

characteristic forms of the South-Tethyan margin, being known Spiti Shale ammonite species were able to survive in such

mainly from the Spiti area of the Himalaya (Uhlig, 1903–1910). In shallow-water environments, and the so-called Late Jurassic

fact, all ammonite names that Fan et al. (1988) listed are from a book, ammonites recorded from above are likely to have been

in which the ammonites from the Agri area, Himalayan Tibet, misidentiﬁed, as highlighted by Yin (2005), Yin et al. (2005)

originally studied by Uhlig (1903–1910) have been re-ﬁgured and and Yin (2010a,c).

re-described in a Chinese translation by Zhao (1965). A recent study on ammonites from Qiantang has made it

Yi et al. (2003) provided a further list of ammonites from the possible to date the age of the Suowa, Xiali, and Buqu formations as

Suowa Formation in the Bandaohu (Changhonghe) area: Aulaco- Middle Jurassic. In northern Qiangtang three ammonite levels were

sphinctoides sp., A. infundibulum, A. hollandi, A. rareplicatus, A. recognized in the Buqu Formation of the Cuoriju section (N 33840 ,

moerikeanus, A. spitiensis, Virgatosphinctes dacquei, V. haydeni, V. E 91840 ) (see Fig. 13). The specimens have been referred to

multifasciatus, V. frequens, V. lemoinei, V. broilli, V. kutianus, V. Procerites sp., Siemiradzkia cf. matisconensis (Lissajous, 1923),

indistinctus, V. subfrequens, V. holdhausi, Haplophylloceras, Blanfor- Neuqueniceras cf. yokoyamai Kobayashi and Fukada, 1947, and

diceras cricki, B. celebrant, Berriasella, Paraboliceras spitiense, Choffatia (Choffatia) cf. vicenti Mangold, 1970, indicating a Middle

Dhosaites sp., Uhligites griesbachi, Substeueroceras sp., and Kossma- to Late Bathonian age (Yin, 2005). About 120 km south of the

tia sp. These are well known taxa of the Spiti Shale fauna described Yanshiping section an isolated specimen from the Suowa Forma-

by Uhlig (1903–1910) and are mainly Tithonian elements. tion has been referred to Reineckeia (Yin, 2005). Westermann and

Unfortunately, as in the case of ammonites, reported by Fan Wang (1988) described Macrocephalites cf. macrocephalus from the

et al. (1988), it is impossible to examine these ‘so-called’ Tithonian neighbourhood of Dingqing.

specimens, because their whereabouts is unknown. Since that time It is pertinent that Lu and Xu (2001) provided an ammonite

ammonite names listed by Fan et al. (1988) and Yi et al. (2003) have list with ﬁgures from the Xiali Formation in the Changhonghe

repeatedly been cited to document the Late Jurassic (mainly section, including Oxycerites sp., Choffatia cf. madani Spath, C. cf.

Tithonian) age of the Suowa Formation (Sun and Xu, 1998; Fang baliensis (Neumayr, 1875), and Macrocephalites cf. macrocephalus

and Liang, 2000; Fang et al., 2000, 2002; Li et al., 2005; Lu and Xu, (Schlotheim, 1813). These authors therefore regarded the Xiali

2001; Wang et al., 2001, 2009; Yi et al., 2005; Tan et al., 2004; Zeng Formation as Callovian in age. However, the species cited by Lu and

et al., 2012a,b) (Fig. 2). Xu (2001) has now been revised as Oxycerites orbis (Giebel, 1852),

It is known that the Late Jurassic ammonite faunas of the so- Macrocephalites madagascariensis Lemoine, 1911, respectively (see

called Spiti Shales are characterized by a high level of endemicity below). Thus, the Xiali Formation has been proven on the basis of

at the generic level within the southwestern Paciﬁc region (Page, these ammonites to contemporary with the Suowa Formation

1996; Enay and Cariou, 1997; Enay and Cariou, 1999; Hallam, (Bathonian–early Middle Callovian) in the Chonghonghe section,

2001; Yin and Enay, 2004; Enay, 2009). In Himalayan Tibet, a sea- this is further demonstrated below.

level rise in the latest Early Tithonian is well documented, ﬁrst by Yi et al. (2005) have listed many Late Jurassic ammonites from

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the Virgatosphinctes broilli-raja group assemblage, then by the the 114 Daoban section (N 32826 , E 92817 ), Amdo county in the

Uhligites-Aulacosphinctes-Pseudolissoceras assemblage, and ﬁnally southern Qiangtang Basin, such as Blanfordiceras, Aulacosphinctes,

by the Haplophylloceras assemblage of the earliest Late Tithonian, Virgatosphinctes and Spiticeras. It is again impossible to examine

when the sea level reached its maximum (Yin, 2007). In contrast to this ‘so-called’ Tithonian assemblage. However, two specimens

the Himalayan region, the Suowa Formation in northern which they considered to be the best preserved were referred to

Qiangtang is proven to be a regressive sequence, changing from Blanfordiceras curvatum Uhlig (Yi et al., 2005, pl. 1, Fig. 9) and

inner shelf to tidal-inﬂuenced environments (Yin, 1989a, 1991; Aulacosphinctes hollandi Uhlig (Yi et al., 2005, pl. 1, Fig. 11),

Tan et al., 2004; Jin et al., 2006; Zeng et al., 2012a,b). The sudden respectively. These are, to date, the only published ﬁgured

appearance of so many taxa in northwestern Qiangtang, which specimens of the presumed Tithonian ammonites from the

previously had only been known from the western Himalayas, Qiangtang area. These two specimens are re-ﬁgured here (Fig. 3)

raises doubts, not only because the Suowa Formation differs from despite their poor preservation.

250 J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265

Fig. 3. Ammonite specimens (re-figured), first illustrated and identified as Blanfordiceras curvatum Uhlig (left) and Aulacosphinctes hollandi Uhlig by Yi et al. (2005, pl. 1, Figs.

9 and 11) (right).

Professor Yi made a second ammonite collection from the 114 Eucycloceras cf. cogginbrowni Spath

Daoban section in 2001. The specimens were sent to the author for Nothocephalites asaphus Spath [m]

examination. The ammonites occur at the top of the Suowa Nothocephalites semilaevis (Waagen) [M]

Formation. The results of the study was published some years ago Macrocephalites compressus (Quenstedt)

(Yin, 2005, 2010a), indicating that the Suowa Formation in Choffatia cf. sakutala Spath

southern Qiangtang is also Middle rather than Late Jurassic in Choffatia (Subgrossouvria) recuperoi (Gemmellaro)

age. In 2003 colleagues from the China University of Geosciences in Macrocephalites madagascariensis Lemoine

Beijing collected ammonites from the Suowa Formation at the 114 Oxycerites orbis (Giebel)

Daoban section. The Suowa Formation here is about 800–900 m

thick, and Neuqueniceras cf. yokoyamai Kobayashi et Fukada, Oxycerites orbis (Giebel) has been known from the Tibetan

Oxycerites sp. and Homoeoplanulites sp. have been found in the Himalayas and southern Qiangtang (Yin, 2010a,b) and Kachchh

upper part of it. These ammonites from both the southern and (Jain, 2014) before, it occurs in both the Xiali and Suowa

northern Qiangtang indicate that the age of the Suowa Formation is formations. This implies that not only parts of the Suowa

Middle Jurassic (Yin, 2005, 2010a,c). Formation represent the Upper Bathonian but also parts of the

underlying Xiali Formation.

2. Ammonite assemblages from the Changhonghe section, Macrocephalites madagascariensis Lemoine, a species which has

northwestern Qiangtang been known from Madacascar (Lemoine, 1911; Collignon, 1958),

Kachchh (Spath, 1928; Krishna and Westermann, 1987; Roy et al.,

This study is based on a new collection from the Changhonghe 2007) and Germany (Schlegelmilch, 1985). It has been known from

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section (N 34805 , E 88819 ) in the Bandaohu area, northwestern the Lower Callovian of Kachchh previously (Krishna and Wester-

Qiangtang, made by Zeng from the Chengdu Institute of Geology mann, 1985, 1987), but is now regarded as indicating the topmost

and Mineral Resources of the China Geological Survey Bureau in Upper Bathonian strata (Roy et al., 2007; Jain and Desai, 2014). The

2011. In the ﬁeld the ammonite-bearing beds occur in the Suowa number of endemic ammonite species within the Indo-Malgach

Formation, and the formation has been regarded as the Upper faunal Province is now greatly reduced within Kachchh, proven not

Jurassic in age, and overlain by the Xueshan Formation (Zeng, pers. only by Macrocephalites madagascariensis (Krishna and Cariou,

comm. 2011, also see Fig. 4). The ammonites were kindly sent to 1990, 1993; Jain, 2014) but also by the occurrence of Reineckia in

the author together with stratigraphical information. The section is Kachchh and northern Qiangtang (Cariou and Krishna, 1988; Yin,

composed of the Xiali, Suowa and Xueshan formations, and the 2005) and of Neuqueniceras in Himalayan Tibet (Yin, 1996) and

primary identiﬁcation done by the author, was published in a Nothocephalites semilaevis and N. asaphus from Kachchh in

report by Zeng et al. (2012a). Qiangtang (the present account).

The ammonites studied in the present paper are from two levels Evidence of Lower Callovian strata are Nothocephalites semi-

in the Suowa Formation of the Changhonghe section: laevis, N. asaphus, Macrocephalites compressus (Quenstedt), and

Level 1: Ammonites from Bed 8 with a thickness in 35 m, Choffatia (Subgrossouvria) recuperoi (Gemmellaro). Nothocephalites

associated with bivalves and brachiopods in the base of the bed, has been regarded as endemic to Kachchh in the past, and

Gracilisphinctes suprapanatinus Arkell occurs. This species, origi- Nothocephalites semilaevis is an indicator of the Semilaevis Subzone

nally known from the Aspidoides Bed in Schwandorf, Southern at the top of the Lower Callovian (Krishna and Westermann, 1987;

Germany (Arkell, 1951b), is regarded as an indicator of the early Jana et al., 2005). Macrocephalites compressus was ﬁrst found in

Middle Bathonian. Gracilisphinctes suprapanatinus is the ﬁrst Sicily, Italy (originally by Gemmellaro, 1873, and revised by Pavia

evidence of the Middle Bathonian in northwestern Qiangtang. and Cresta, 2002, p. 265, Fig. 181), and subsequently in the

Level 2: Bed 18 is 16 m thick, and consists of siltstone, limestone, Formosus Zone or in the Gracilis Zone in Kachchh (Spath, 1928;

and sandy limestone. About 60 samples in total have been Jaitly and Singh, 1984) and in Germany and France (Schlegelmilch,

labelled as Bed 18 but their precise horizon remains unknown. It 1985; Mangold, 1970). This ammonite has not been previously

appears that they have been collected from scree as most reported from Tibet.

specimens are partly covered with a secondary calcareous crust Eucycloceras cf. cogginbrowni is a fairly large ammonite in

due to weathering. The surface of the specimens has been diameter, and corresponds closely to Subkossmatia cogginbrowni

discoloured pink by the iron content in the surrounding matrix. Spath (1928, p. 212, pl. 31, Fig. 6; pl. 41. Fig. 4a–c) with respect to

No suture lines are preserved. The following forms have been ribbing and its wide umbilicus. Jana et al. (2005) in their contribution

identiﬁed from level 2: on Eucycloceratinae, suggest Subkossmatia cogginbrowni to be a

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 251

Fig. 4. Ammonite levels of the Changhonghe section, northern Qiangtang.

synonymy of Subkossmatia opis, and that Subkossmatia should be indicated. The following parameters were measured: D, diameter

replaced by Eucycloceras. Eucyloceras opis is a subzonal species in the of the shell (mm); H, height of whorl section (mm); U, umbilical

basal Middle Callovian in Kachchh (Jana et al., 2005). Taking into diameter (mm); W, width of whorl section (mm); h, H/D; u, U/D; w,

account the biostratigraphical framework of Kachchh, ammonites of W/D; r/WH, number of ribs per half whorl; Ph and BC refer to

the Changhonghe section document the Early Late Bathonian, phragmocone and body-chamber, respectively. [M], macroconchs;

Oxycerites orbis assemblage, Late Bathonian Macrocephalites mada- [m], microconchs. All photographs are natural size, and the scale

cascariensis assemblage, and a late Early Callovian assemblage, bar is 50 mm except when otherwise stated. Specimen numbers

represented by Macrocephalites compressus and Choffatia (Subgros- bear the following institutional repository preﬁx: A2014CUGB,

souvria) recuperoi, Nothocephalites semilaevis and N. asaphus. These China University of Geosciences, Beijing. Specimens are deposited

species represent the topmost Early Callovian in both Kachchh and in the Museum of the University.

Qiangtang, and Eucycloceras cf. cogginbrowni and Choffatia cf.

sakutala most likely indicate the basal Middle Callovian (Fig. 5). Class CEPHALOPODA Cuvier, 1795.

Subclass AMMONOIDEA von Zittel, 1884.

3. Systematic palaeontology Order AMMONITIDA Fischer, 1882.

Suborder AMMONITINA Fischer, 1882.

The classiﬁcation follows the Treatise on Invertebrate Paleon- Superfamily Haploceratoidea von Zittel, 1884

tology (Arkell et al. (1957) and Donovan et al. (1981) and more Family Oppeliidae Bonarelli, 1894

recent amendments (e.g., Roy et al., 2007; Alberti et al., 2015), as Subfamily Oppeliinae Douville´, 1890 252 J.

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Fig. 5. Ammonite assemblages from the Changhonghe section in northern Qiangtang and correlation with the ammonite zones of Kachchh, western India and West Tethys.

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Genus Oxycerites Rollier, 1909 2001 Macrocephalites cf. macrocephalus (Schlotheim, 1813);

Type species. Ammonites aspidoides Oppel, 1857 Lu et Xu, pl. 30, Figs. 8 and 9 [without description].

2001 Cadomites? sp.; Lu et Xu, pl. 31, Figs. 9 and 10 [without

Oxycerites orbis (Giebel, 1852)

description].

Fig. 10, d1–3

2007 Macrocephalites madagascariensis Lemoine; Roy et al., p.

1852 Ammonites orbis sp. n.; Giebel (re-ﬁgured in Dietl, 1982). 630, Fig. 2.

1967 Oxycerites oppelli sp. n.; Elmi, p. 534, pl. 1, Figs. 1–5. 2012 Macrocephalites cf. compressus (Quenstedt, 1846);

Seyed-Emami et al., p. 53, Fig. 6e, f.

1982 Oxycerites orbis (Giebel); Dietl, p. 1–21, pl. 3, Figs. 1–3.

2012a Macrocephalites cf. verus (Buckman, 1922); Zeng et al.,

1997 Oxycerites oppeli Elmi; Cariou and Hantzpergue, pl. 18,

pl. 2, Fig. 4a, b.

Figs. 7 and 8.

2001 Oxycerites sp.; Lu and Xu in Zhao et al., pl. 31, Figs. 1 and 2. Material. 16 specimens including one body-chamber and ﬁve

relatively complete phragmocones and whorl fragments

2005 Oxycerites oppeli Elmi; Yin, p. 4; pl. 2, Fig. 4a, b.

A2014CUGB1011-1013, 1018–1020 (illustrated) and

2010a Oxycerites orbis (Giebel); Yin, p. 99, pl. 1, Figs. 5, 7–9, pl. 2, A2014CUGB2010-2019.

Figs. 1–3.

Description. Specimens highly weathered; partly covered with

Material. One incomplete phragmocone from the scree of Bed 18 in calcareous crust and stained pink. Suture not seen; diameter

the section studied (A2014CUGB1014). varying from 36 to 114 mm, maximum rate of shell thickness to

Description. This extremely involute, compressed oxyconic shell diameter 50 (wh/D 100), umbilicus deep and moderately

specimen is the last whorl of a phragmocone with D 75 mm. wide with steep wall and well-deﬁned margin. Primary ribs

Whorl ﬂank with median spiral ridge corresponding to the number about 36–40 per whorl, counted along the umbilical seam,

maximum whorl width (17 mm). Series of short, narrow arcuate and well developed. Starting from the lower margin of the

ribs developed in the upper quarter of ﬂank height. Ribs widely umbilicus, they are usually rursiradiate near the umbilical seam,

spaced, usually numbering 16–20 per whorl. Inner whorl ﬂanks then sweep slightly forward, on the median whorl-side appear

smooth. secondary ribs, including intercalated simple and bifurcated ribs.

Remarks. Both Elmi (1967) and Dietl (1982) recognized that it is On the outer whorl ﬂank the ribs become coarse, rounded, nearly

not correct to designate Oxycerites aspidoceras (Oppel) as the index identical to each other in strength, and pass straight over the

species of the Late Bathonian Aspidoceras Zone as has been done in venter. Maximum shell thickness slightly below the middle of the

the early literature, because the holotype of Oxycerites aspidoceras whorl ﬂank; whorl cross-section sub-triangular with broad,

(Oppel) was found in the Parkinsoni or Zigzag Zone. Dietl (1982) rounded venter.

suggested to replace the Aspidoceras Zone by the Orbis Zone with Remarks. ‘‘The ammonite of the genus Macrocephalites must rank

Oxycerites orbis (Giebel, 1852) as the index species. Oxycerites among the most familiar to geologists and palaeontologists the

oppelli Elmi, 1967 has been thought to be a junior synonym of world over. . .’’ (Callomon, 1971, p. 114), however, the genus has

Oxycerites orbis (Dietl, 1982). Oxycerites has recently been recorded rarely been recorded from the Qiangtang Block before, although

from both Himalayan Tibet (Yin et al., 2000; Yin, 2010a) and Jurassic strata are widely distributed in the region. To date, the

Qiangtang, North Tibet (Lu and Xu, 2001; Yin, 2005). Both the present specimens number the largest macrocephalitid collection

Himalayan and the present specimen greatly resemble the from Qiangtang (North Tibet), consisting of the madagascariensis-

specimen, referred to Oxycerites orbis by Giebel, 1852, re-ﬁgured group and compressus-group, whereby the former is dominant and

by Dietl (1982), with respect to the inﬂated spiral ridge and the best matches Macrocephalites madagascariensis Lemoine (Spath,

short, widely interspaced ribs. The present specimen is incomplete, 1928, p. 181, pl. 22, Fig. 3) in having more inﬂated whorls, a wider

and the suture line is not visible. umbilicus and somewhat coarse ribs. In addition, there are

specimens whose measurements are transitional between the

two groups, which also are referred to Macrocephalites madagas-

Superfamily Stephanoceratoidea Neumayr, 1875

cariensis rather than the compressus group based on their costation

Family Sphaeroceratidae Buckman, 1920

and the number of ribs (Fig. 9).

Subfamily Macrocephalitinae Salfeld, 1921

Specimens referred to Macrocephalites madagascariensis were

Genus Macrocephalites Zittel, 1884

collected from ammonite level 2 in the Changhonghe section. Most

Type species. Ammonites macrocephalus Zittel, 1884, p. 470, Fig.

655 of the specimens are phragmocones, only one specimen is

preserved with body-chamber and reaches 114 mm in diameter.

Macrocephalites madagascariensis Lemoine, 1911[M] and [m] It matches specimen from Kachchh best (Krishna et al., 1988, pl. 2a,

Fig. 6, a1–3, b1–2, c1–2; Fig. 7, a1–2; Fig. 10, e1–2, f1–2, g1–2 b), its last whorl is smooth, the length is about one-quarter of a

whorl, and its phragmocone seems to be complete with a diameter

1911 Macrocephalites madagascariensis sp. nov; Lemoine, p.

of about 90 mm. This is nearly as large as the phragmocones of

51, 1910, pl. 5, Fig. 3a, b.

three other well-preserved specimens in the collection, indicating

1928 Macrocephalites madagascariensis Lemoine; Spath, p. that the specimen with the body-chamber preserved is an adult.

181, pl. 22, Fig. 3a, b. The Tibetan specimens preserved as phragmocones agree well

with Macrocephalites madagascariensis from Kachchh (Spath, 1928,

1971 Macrocephalites madagascariensis Lemoine; Callomon,

p. 181, pl. 22, Fig. 3a, b). Superﬁcially, the present madagascar-

p. 114–130.

iensis-group resembles also Macrocephalites verus Buckman from

1985 Macrocephalites (Macrocephalites) madagascariensis

Ehningen (Wu¨ rttemberg), Germany (Buckman, 1922, pl. 334A,

Lemoine; Schlegelmilch, p. 105, pl. 37, Fig. 6.

Figs. 1 and 2), but differs mainly in the position of the maximum

1987 Macrocephalites madagascariensis Lemoine; Krishna and

thickness on the whorl ﬂank. The maximum thickness of

Westernmann, p. 1574–1575, pl. 2, Fig. 3.

Macrocephalites verus is near the umbilicus, which results in a

1988 Macrocephalites madagascariensis Lemoine; Krishna, narrower sub-triangular cross-section of the last whorl (body-

Cariou and Enay, p. 387, pl. 2, Fig. 1a, b. chamber) than in Macrocephalites madagascariensis. In addition, the

254 J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265

Fig. 6. a1–3, b1–2, c1–2. Macrocephalites madagascariensis Lemoine. a1, lateral view, a2, cross-section, a3, ventral view of a well preserved specimen, A2014CUGB1019. b1,

lateral view, b2, ventral view, A2014CUGB1020 and this specimen shows its cross-section transitional between Macrocephalites madagascariensis and Macrocephalites

compressus. c1, ventral view, c2, lateral view, A2014CUGB1018 with outer whorls. The black arrow denotes the estimated start of the body-chamber. Scale bar = 50 mm.

primary ribs at the umbilical seam vary between 36 and 50 in studied the related specimens available in European museums. He

number, which is a little less than those of Macrocephalites verus, suggested that the three species should be neotypes of a

moreover, the ribs are coarser and less dense as in Macrocephalites biospecies, and regarded Macrocephalites macrocephalus Zittel as

verus. type species of the genus. In addition, in his synonymy list of

Macrocephalites madagascariensis has been recorded from the Macrocephalites macrocephalus Zittel (Callomon, 1971, p. 127) he

Changhonghe section before, identiﬁed as Macrocephalites cf. included the formosus-madagascariensis group of Spath (1928) as

macrocephalus (Schlotheim) from the Suowa Formation and as the Indian equivalent of the European Macrocephalites macro-

Cadomites? sp. from the Xiali Formation (see synonymy list). cephalus. Callomon (1971, p. 126) regarded ten species of the early

Westermann and Wang (1988) identiﬁed an isolated specimen classical literature as synonymy of Macrocephalites macrocephalus

from the Dingqing area as Macrocephalites cf. macrocephalus, but its Zittel, including M. madagascariensis Lemoine, 1911 and M.

whorl cross-section is much more inﬂated than that of Macro- compressus Quenstedt, 1849. However, Callomon et al. (1992)

cephalites madagascariensis. had revised his early conclusions.

Callomon (1971) traced the history of Macrocephalites macro- One of the present specimens was previously referred to as

cephalus (Schlotheim, 1813), Macrocephalites macrocephalus Zittel, Macrocephalites cf. verus (Buckman, 1922) by the author (see

1884, and Macrocephalites verus Buckman, 1922 in detail and synonymy list).

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 255

Fig. 7. a1–2. Macrocephalites madagascariensis Lemoine. a1, lateral view, a2 ventral view, A2014CUGB1022. The whorl cross-section of this specimen is transitional between

M. madagascariensis and M. compressus. b1–2, c1–3. Macrocephalites compressus (Quenstedt). b1, lateral view, b2, ventral view of inner whorls, A2014CUGB1023. c1, ventral

view, c2, cross-section, c3, lateral view, A2014CUGB1021. d1–2, e1–3. Nothocephalites asaphus Spath, 1928 [m]. d1, lateral view, d2, ventral view, A2014CUGB1025. e1, lateral

view, e2, cross-section of whorls. e3, ventral view, A2014CUGB1024. Scale bar = 50 mm.

Macrocephalites compressus (Quenstedt, 1846) 2001 Epimayaites? sp.; Lu and Xu, pl. 33, Figs. 12 and 13.

Fig. 7, b1–2, c1–3

2012a Macrocephalites cf. gracilis (Spath, 1928); Zeng et al. pl.

2, Fig. 5a, b.

1846 Ammonite macrocephalus compressus sp. nov.; Quen-

Material. Three specimens, two phragmocones specimen illus-

stedt, p. 184, pl. 15, Fig. 1.

trated (A2014CUGB1021, 22), and one small individual.

1907 Macrocephalus compressus Quenstedt; Blake, p. 45, pl. 4,

Description. Whorl cross-section elliptical with somewhat

Fig. 4.

ﬂattened venter. Ribs sweeping radially and not combining

1985 Macrocephalites compressus (Quenstedt, 1846); Schle- into groups near the umbilicus, but bifurcated half way up

gelmilch, p. 226, pl. 38, Fig. 1. the whorl ﬂank which is only faintly arched. Greatest thickness

256 J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265

between the umbilical seam and the middle of the whorl likely a preservation artefact. Nothocephalites has only been known

ﬂank. from Kachchh until now. The suggestion of Jana et al. (2005) that

Remarks. In the present collection Macrocephalites compressus is Nothocephalites asaphus is a microconch and N. semilaevis a

distinctly thinner and more involute than M. madagascariensis. It macroconch is accepted here (see below).

differs from M. madagascariensis by its ﬁne and regular ribs.

Nothocephalites semilaevis (Waagen, 1875) [M]

Macrocephalites compressus differs from the compressed Macro-

Fig. 8, a1–3; Fig. 11, c1–2; Table 2

cephalites gracilis (Spath, 1928) by fewer ribs and greater inﬂation.

Both species are well known from Europe (England and Germany).

1875 Stephanoceras semilaeve sp. nov.; Waagen, p. 119, pl. 28,

In Kachchh, Macrocephalites madagascariensis and M. lamellosus

Fig. 3a, b.

(Lemoine, 1911) apparently form a dimorphic pair (Krishna and

Westermann, 1987), but Macrocephalites compressus is character- 1928 Nothocephalites semilaevis (Waagen); Spath, p. 207, pl.

ized with finer ribs and more flattened flanks, and is less inflated 30, Fig. 1; pl. 33, Fig. 12; pl. 36, Fig. 9; pl. 38, Fig. 4.

than M. lamellosus. Macrocephalites formosus (Sowerby, 1840) 1987 Macrocephalites semilaevis (Waagen); Krishna and

found in the Golden Oolite of Kheera Dome, Kachchh; it differs Westermann, p. 1580, pl. 4, Fig. 4.

from the present species by its subtriangular whorl cross-section

Material. Two macroconchs (A2014CUGB1026-27).

(Krishna and Westermann, 1987, p. 1576, pl. 5, Fig. 1a, b).

Description. The larger specimen (about 200 mm in diameter) is

Specimens referred to Macrocephalites cf. compressus (Quenstedt,

preserved with incomplete body-chamber, the other (100 mm in

1846) by Seyed-Emami et al. (2012, p. 53, Fig. 6e, f) is more inﬂated

diameter) is a phragmocone. Apart from their size the macro-

than the present Macrocephalites compressus and more similar to

conchs specimens differ from Nothocephalites asaphus [m] by

Macrocephalites madagascariensis. Epimayaites? sp. previously

inﬂated whorls. Region of greatest inﬂation is near the middle of

recorded from the Suowa Formation of the Changhonghe section

the whorl ﬂank, the whorl cross-section lenticular, the umbilicus

(Lu and Xu, 2001, pl. 33, Figs. 12 and 13) is compressed and its

narrow, incised with rounded shoulder. Style of ribbing apparently

whorl cross-section is identical to that of the present Macro-

as in the microconch, only simple, slightly prorsiradiate ribs.

cephalites compressus. There is no evidence that the range of

Venter more arched than in the microconch, ribs disappearing at a

Epimayaites extended beyond the Malgach Gulf and adjacent

diameter of about 200 mm, indicating that the complete shell

regions at the southern margin of the Tethys, the Oxfordian

would be much larger than the present specimens.

Subfamily Mayaitinae consisting largely of endemic taxa (Alberti

Remarks. The two macroconch specimens referred to Nothoce-

et al., 2015). This specimen was identiﬁed previously by the author

phalites semilaevis (Waagen) are characterized by their distinct

as Macrocephalites cf. gracilis (Spath, 1928) (see Zeng et al., 2012a,

whorl cross-section, in which they differ from Macrocephalites

and synonymy list).

formosus and Nothocephalites asaphus. Waagen (1875) recorded the

Subfamily Eucycloceratinae Spath, 1928 size of four specimens, the largest being 180 mm in diameter. Their

Genus Nothocephalites Spath, 1928 narrow umbilicus makes the Tibetan specimens identical to

Type species Nothocephalites asaphus Spath, 1928 Waagen’s type, but they differ in this respect from the specimens

of Spath (1928, pl. 30, Fig. 1; pl. 33, Fig. 12), this was also

Nothocephalites asaphus Spath, 1928 [m]

recognized by Spath (1928). Nothocephalites mondegoensis (Spath,

Fig. 7, d1–2, e1–3

1928, p. 207, pl. 36, Fig. 16) is quite evolute, unlike the present

Nothocephalites semilaevis (Waagen) [M] and Nothocephalites

1928 Nothocephalites asaphus sp. nov.; Spath, p. 208, pl. 28,

asaphus Spath [m].

Fig. 2a, b.

Subfamily Eucycloceratinae Spath, 1928

Material. Two microchonch specimens (A2014CUGB1024-25).

Genus Eucycloceras Spath, 1924

Description. Compressed and involute, 62 and 68 mm in diameter,

Type species. Stephanoceras eucyclum Waagen, 1875

respectively, whorl ﬂanks fairly ﬂat, venter arched. Greatest

inﬂation near the umbilicus, producing an elongated-subquadrate

Eucycloceras cf. cogginbrowni Spath, 1928

whorl cross-section. Umbilicus narrow, deep; primary ribs simple,

Fig. 8, b1–2

coarse, dense, slightly prorsiradiate, starting at the rounded

umbilical edge. At the middle of the ﬂank simple secondary ribs

cf. 1928 Subkossmatia cogginbrowni Spath; p. 212, pl. 31, Fig. 6;

are intercalated. Ribs crossing the venter, suture unknown.

pl. 41, Fig. 4a–c.

Remarks. Spath (1928) placed Nothocephalites, Eucycloceras,

Subkossmatia, and Idiocyloceras within the family Eucycloceratidae. Material. One specimen (A2014CUGB1028).

Nothocephalites differs from Eucycloceras mainly by being involute, Description. Poorly preserved, compressed specimen, both umbi-

from Macrocephalites by its simple ribbing and compressed, licus and ribbing distinct. Ornamentation consisting of simple and

planulate shape. Nothocephalites shares some features with bifurcated ribs which are stout, coarse and weakly prorsiradiate;

Macrocephalites such as being involute and having a smooth adult umbilicus very wide with rounded shoulder and steep wall. Whorl

body-chamber. Donovan et al. (1981) regarded eucycloceratinids ﬂanks ﬂat, venter arched, whorl cross-section elliptical, suture

as the sub-Austral and Indo-Malgach descendents of Macrocepha- unknown.

lites into the Middle Callovian, and worth retaining as a separate Remarks. The Tibetan specimen is fairly large, and matches

Subfamily, which is followed here. Spath (1928) recognized four Subkossmatia cogginbrowni Spath (1928, p. 212, pl. 31, Fig. 6; pl. 41,

species of Nothocephalites, the closest to the Tibetan specimens Fig. 4a–c) in its characteristic ribs and umbilicus. Jana et al. (2005)

being Nothocephalites asaphus which was established on a single revised in detail Spath’s Eucycloceratinae, suggesting that Sub-

specimen (Spath, 1928, p. 208). The Tibetan specimens referred to kossmatia cogginbrowni is a synonymy of Subkossmatia opis and

Nothocephalites asaphus are a little larger than the HT, but they share replaced Subkossmatia by Eucycloceras. The Tibetan specimen is

the same style of ribbing. The ribs of the Tibetan specimens are not as almost 100 mm in diameter, even though not completely

ﬁne as those of the HT; they seem to be somewhat swelling, possibly preserved. Subkossmatia cogginbrowni (= Eucyclocera opis accord-

due to a weathering crust. Spath (1928) mentioned that the inner ing to Jana et al., 2005) is thought to be a microconch, whereas the

ﬂanks of whorls in the HT are smooth, without ribs, but this is most present specimen is likely the phragmocone of a macroconch.

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 257

Fig. 8. a1–3. Nothocephalites semilaevis (Waagen) [M]. a1, cross-section, shaded area: body-chamber, a2, lateral view with outer whorls, the black arrow possibly denotes the

start of the body-chamber, a3, ventral view of inner whorls, A2014CUGB1027. b1–2. Eucycloceras cf. cogginbrowni Spath, 1928. b1, lateral view, b2, ventral view,

A2014CUGB1028. Scale bar = 50 mm.

Superfamily Perisphinctoidea Steinmann, 1890 Material. Three specimens A2014CUGB, 1011–1013.

Family Perisphinctidae Steinmann, 1890 Description. Shell compressed planispiral, whorl width in-

Subfamily Zigzagiceratinae Buckman, 1920 creased rapidly during ontogeny, umbilicus wide with a sloping

Genus Gracilisphinctes Buckman, 1920 wall. More than six whorls can be seen. Inner whorls with two or

Type species. Ammonites gracilis Buckman, 1920 three constrictions per whorl. Ribs on inner whorls strong,

primary ribs rectiradiate, regularly interspaced, bifurcating at

Gracilisphinctes suprapanatinus Arkell, 1951b [m]

around two-thirds of ﬂank height. Secondary ribs with

Fig. 10, a1-2, b1-3, c1-3; Table 1

intercalated simple ribs, identical in strength. Height of last

whorl increasing rapidly, whorl section oval in outline. Outer

1951b Gracilisphinctes suprapanatinus sp. nov.; Arkell, p. 13, pl.

whorl of specimen (Fig. 10, a1) 89 mm in diameter, outer whorl

3, Fig. 2a, b.

apparently smooth. Specimen (Fig. 10, c3) fairly evolute, 74 mm

2012a Homoeoplanulites cf. baliensis (Neumayr, 1873); Zeng in diameter, the whorl following a constriction smooth.

et al. pl. 1, Fig. 5. Specimen (Fig. 10, a) consists of inner whorl with two or three

2012a Homoeoplanulites cf. pseudoanularis (Lissajous, 1923); constrictions per whorl, whorl section subquadrate, suture not

Zeng et al. pl. 2, Fig. 1a, b. seen.

258 J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265

Fig. 9. Diagram of whorl section of Macrocephalites and Eucycloceras from the Changhonghe section, northwestern Qiangtang.

Remarks. These specimens were identiﬁed previously by the 1873 Perisphinctes recuperoi sp. nov. Germmellaro, p. 26, pl. 5,

author as Homoeoplanulites cf. baliensis (Neumayr, 1873) and H. Figs. 9 and 11.

cf. pseudoanularis (Lissajous, 1923) (see synonymy). Even with

1928 Choffatia (Subgrossouvria) recuperoi (Gemmellaro); Spath,

complete body-chamber, the size of the three Tibetan specimens

p. 358.

would be much smaller than Arkell’s holotype from Germany.

1958 Choffatia (Loboplanulites) recuperoi (Gemmellaro); Arkell,

Consequently they are probably microconchs. The umbilicus in

p. 221, text-ﬁg. 80, 1a,b [re-ﬁgured Gemmellaro, 1873]

any of the species known from Kachchh, (Pandey and Callomon,

1995; Roy et al., 2007; Jain, 2014) and Europe (Westermann, 1970 Choffatia (Subgrossouvria) recuperoi (Gemmellaro); Man-

1958; Schlegelmilch, 1985), except Gracilisphinctes suprapana- gold, p. 161; pl. 10, Figs. 2 and 3.

tinus Arkell, 1951b, is not as wide as that in the Tibetan 2002 Choffatia (Subgrossouvria) recuperoi (Gemmellaro); Pavia

specimens. Collignon (1958) erected three new species of and Cresta, p. 265, ﬁg. 181 [re-ﬁgured the specimen of

Gracilisphinctes from Madagascar: Gracilisphinctes arkelli (Col- Gemmellaro, 1873].

lignon, 1958, pl. 6, Figs. 31–33), Gracilisphinctes lemoinei (pl. 7,

2012a Homoeoplanuites cf. furculus (Neumayr, 1871); Zeng et al.

Fig. 35) and Gracilisphinctes andranomantsyensis (pl. 7, Fig. 36).

pl. 1, Fig. 3.

All of them show a relatively narrow umbilicus. Pandey and

2012a Homoeoplanulites cf. acuticosta (Roemer, 1911); Zeng et al.

Callomon (1995) illustrated numerous well preserved speci-

pl. 1, Fig. 2a, b.

mens from Kachchh, referred to Gracilisphinctes arkelli, suggest-

ing that all three species erected by Collignon (1958) should be Material. Nine relatively complete specimens with some whorl

regarded as Gracilisphinctes arkelli. Recently Jain (2014) de- fragments (A2014CUGB1030-32, 35, 37, 39 illustrated and

scribed Procerites (Gracilisphinctes) intermedius Jain [m] and A2014CUGB2020-21).

Procerites (Gracilisphinctes) progracilis arkelli Collignon [M] and Description. Evolute shells with wide umbilicus, rounded

[m] from Kachchh. The Tibetan Gracilisphinctes suprapanatinus umbilical shoulder, and steep umbilical wall. Regarding the

differs from the Kachchh specimens by being more compressed, ribbing, the last complete whorl carries between 26 and 27 ribs.

with ﬂatter ﬂanks and a wider umbilicus, and in having The primary ribs are sharp, strong, regularly but distantly spaced

pronounced whorl constrictions; all these features can be and they trifurcate into secondaries slightly ventrally of the middle

observed on both Tibetan and German specimens of Gracili- of the whorl ﬂank. Whorls inﬂated and cross-section of whorl

sphinctes suprapanatinus. Superﬁcially, the Tibetan Gracili- circular to subtrapezoidal. Last whorl of the large Tibetan specimen

sphinctes suprapanatinus also resembles Procerites (Procerites) 1030 (pl. 7, Fig. 1a, b) with three constrictions, the specimen

quercinus (Hahn, 1969, pl. 8, Fig. 2; Schlegelmilch, 1985, p. 240, terminating with a constriction, at a diameter of 110 mm a

pl. 45, Fig. 1), but the inner three whorls of the Tibetan constriction is followed by a whorl with weak ribs, which probably

specimens consistently have two or three constrictions per indicates the beginning of the body-chamber.

whorl, a feature not visible in Procerites (Procerites) quercinus. Remarks. The best match with the Tibetan specimens is provided

Based on the evolute shell and presence of constrictions, the by specimen of Choffatia (Subgrosouvria) recuperoi from Sicily

best match with the Tibetan specimens is Gracilisphinctes (Gemmellaro, 1873, pl. 5, Figs. 9–11), which has been re-ﬁgured

suprapanatinus from Schwandorf, Bavaria, Germany (Arkell, and described by Arkell (1958) and Pavia and Cresta (2002). In

1951b, p. 13, pl. 3, Fig. 2a, b), and for this reason the Tibetan comparison with French specimen from Chanaz (Savoie) (Mangold,

specimens are placed into Gracilisphinctes suprapanatinus with 1970, p. 161; pl. 10, Figs. 2 and 3) the Tibetan specimen has an

certainty. The present specimens are from ammonite level 1 in identical ribbing style, and the primary ribs of the last complete

the Changhonghe section. Gracilisphinctes suprapanatinus was whorl total, as in the French specimen, 26–27 in number. However,

originally recorded from the Middle Bathonian Aspidoides Bed some of smaller Tibetan specimens show denser and stronger

of Holz-Berg, Schwandorf, Germany (Arkell, 1951b). primary ribs (about 35–40 on the last whorl). In the Tibetan, French

and Italian specimens the distance between ribs increases and

Subfamily Pseudoperisphinctinae Schindewolf, 1925

their number decreases with whorl growth. Thus it is proposed

Genus Choffatia Siemiradzki, 1898

that the differences in ribbing between the specimens most likely

Type species Perisphinctes cobra Waagen, 1875

represent different growth stages. Alternatively, the differences

Choffatia (Subgrossouvria) recuperoi (Gemmellaro, 1873) could represent different ornamentation of macroconchs and

Fig. 11, a1–2, b1–2; Fig. 12, a1–2, b, d; Table 3 microconchs. This cannot be conﬁrmed in the Tibetan specimens

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 259

Fig. 10. a1–2, b1–3, c1–3. Gracilisphinctes suprapanatinus (Arkell) [m]. a1, lateral view, a2, cross-section, shaded area is body-chamber, A2014CUGB1011. b1, lateral view, b2,

cross-section, of lateral view, b3, ventral view, A2014CUGB1013, inner whorls. c1, ventral view, c2, cross-section, c3, lateral view, A2014CUGB1012. Note the smooth whorl

following the constriction at end of the outer whorl. d1–3. Oxycerites orbis (Giebel). d1, ventral view, d2, lateral view, d3, cross-sectional view, A2014CUGB1014. Note that the

specimen is partly covered with a calcareous crust. e1–2, f1–2, g1–2. Macrocephalites madagascariensis Lemoine. e1, lateral view, e2, ventral view, A2014CUGB1015 with inner

whorls. f1, Lateral view, f2, ventral view, A2014CUGB1016. g1, lateral view, g2, ventral view, A2014CUGB1017 with outer whorls. Scale bar = 50 mm.

due to the lack of suture lines. The specimens, illustrated by Zeng species due to the absence of constrictions. In fact, the last whorl of

et al. (2012a), were referred to as Homoeoplanuites cf. furculus the French specimen is clearly terminated by a constriction. Spath

(Neumayr, 1871) and Homoeoplanulites cf. acuticosta (Roemer, (1928, p. 358) thought that the small specimens from Kachchh

1911) previously by the author and are now revised as synonymy ﬁgured by Waagen (1875) are true Choffatia (Subgrossouvria)

here. recuperoi.

Pavia and Cresta (2002) argued that the specimen from France, In Sicily, this species occurs from the topmost Lower Bathonian to

referred to Choffatia (Subgrossouvria) recuperoi (Gemmellaro) by the basal Middle Callovian (Pavia and Cresta, 2002), in Kachchh in

Mangold (1970, p. 161, pl. 10, Figs. 2 and 3) does not belong to the the Lower Callovian Diamatus and Rehmanni zones (Spath, 1928),

260 J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265

Table 1

Measurement of Gracilisphinctes suprapanatinus, G. progacilis and Procerites (Procerites) quercinus.

Specimen (in order from small to large in size) D U u H h W w Appearing in ﬁgure as

Gracilisphinctes suprapanatinus 89.0 35.0 39 30.0 33 25.0 27 1011, pl.1-1

2012 74.0 30.0 40 23.0 31 21.0 28 1012, pl.1-2

2013 35.0 16.0 45 13.0 37 11.0 31 1013, pl.1-3 This paper

Gracilisphinctes suprapanatinus HT 82.0 32.0 39 29.0 35 25.0 30 Arkell (1953)

35.0 18.0 51 9.0 25 12 34

Gracilisphinctes progracilis 146.0 41.0 28 45 30 – – Buckman (1920)

Procerites (Procerites) quercinus 96.0 42.0 46 30.0 30 25.0 26 Schlegelmilch (1985)

and in France possibly also in the Lower Callovian Koenigi Zone Material. Two specimens, A2014CUGB1037 (illustrated), 38.

(Mangold, 1970; Mangold and Rioult, 1997). Description. Whorl-section compressed, the large-sized specimen

being 122 mm in diameter (pl. 9, Fig. 1a, b). Umbilicus wide, whorls

Choffatia cf. sakutala Spath, 1928

slightly compressed, whorl ﬂanks ﬂat, whorl cross-section

Fig. 12, c1–2

consequently narrow-subquadrangular, but this most likely

cf. 1928 Choffatia sakutala sp. nov.; Spath, p. 351, pl. 68, Fig. 4a, b. results from compaction, primary ribs stout, bifurcating into

Fig. 11. a1–2, b1–2. Choffatia (Subgrossouvria) recuperoi (Gemmellaro), a1, lateral view, a2, cross-section, A2014CUGB1030. b1, lateral view, b2, ventral view,

A2014CUGB1039. c1-2, Nothocephalites semilaevis (Waagen), c1, lateral view, c2, cross-section, crushed, possibly phragmocone, A2014CUGB1026. Scale bar = 50 mm.

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 261

Table 2

Measurement of Macrocephalites, Northocephalites and Eucyloceras.

Species D U u H h W w r/h Appearing in ﬁgure as

madagascariensis-group 36.0 5.0 13 15.0 41 15.0 41 1015, p2.1-1

(including transitional forms) 59.0 7.0 11 28.0 47 24.0 40 1016, pl.2-2

69.0 10.0 14 39.0 56 31.0 44 1017, pl.2-3

75.0 9.0 12 42.0 56 31.0 41 18 1022, pl.4-1

83.0 – – 45.0 54 34.0 40 Not illustrated

90.0 15.0 16 45.0 50 40.0 44 17 1021, pl.3-3

93.0 14.0 15 50.0 53 45.0 48 18 1019, pl.3-1,

114.0 10.0 (?) 8 (?) 65.0 57 55.0 48 1018, pl.2-4

compressus-group 35.0 5.0 14 17.0 51 12.0 34 1023, pl.4-2

92.0 9.0 9 50.0 54 33.0 35 25 1023, pl.4-3

Northocephalites asaphus 62.0 9.0 14 34.0 54 21.0 33 – 1024, pl.5-1

68.0 10.0 14 36.0 52 22.0 32 – 1025, pl.5-2

Northocephalites semilaevis 103.0 11.0 10 60.0 58 28.0 27 – 1026, pl.5-3

203.0 15.0 7 112.0 55 72.0 35 – 1027, pl.6-1

Eucyloceras sp. 113 26 23 48 42 37 32 1028, pl.6-2

Fig. 12. a1–2, b, d. Choffatia (Subgrossouvria) recuperoi (Gemmellaro), a1, lateral view, a2, cross section, A2014CUGB1032. b, lateral view, specimen 1031. d, lateral view of the

inner whorls, A2014CUGB1035. c1–2. Choffatia cf. sakutala Spath, c1, lateral view of the inner (?) whorls, c2, cross-section, A2014CUGB1037. Scale bar = 50 mm.

262 J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265

Table 3

Measurement of Choffatia.

Species D U u WW w WH h WW/WH PR/HW Appearing in ﬁgure as

Choffatia recuperoi 118 60 50 22/24 18/20 24/32 20/27 26 1030, pl.7-1

85 40 47 26 30 29 34 25 1033, pl.7-4

85 43 50 22 25 23 27 ? 1032, pl.8-1; pl.7-3

88 37 42 17 19 20 22 – 1034, pl.8-2

98 – 26 26 31 31 – 1031, pl.8-3, pl.7-2

108 55 50 25 23 30 28 16 –

116 60 51 26 22 26 22 13 –

98 48 48 22 22 25 25 15 1038, pl.9-2

Choffatia cf. sakutala 104 52 50 29 28 31 30 14 1037, pl.9-3

122 53 43 22 18 31 25 20 1036, pl.9-1

secondary ribs on the outer whorl ﬂank, occasionally with Bailongbinghe-Bandaohu area. In the northwestern Qiangtang area

intercalated simple ribs. the Jurassic depositional regime of the northern Qiangtang

Remarks. The distinctive whorl cross-section makes it difﬁcult to ﬂuctuated frequently between lagoonal and shallow-water car-

compare this with other species, and it is likely to be a macroconch bonate shelves (Fang and Liang, 2000; Fang et al., 2000; Jin et al.,

due to its large size. The Tibetan specimens resemble Choffatia 2006; Wang et al., 2009; Sun et al., 2013). The Xialia and Suowa

sakutala Spath (1928, p. 351, pl. 68, Fig. 4a, b) in ribbing style and formations in the Changhonghe section show that the lithological

compressed whorl cross-section, but differ by being more evolute succession is almost equivalent in northern Qiangtang, ranging

and having a more compressed whorl cross-section. These from the Middle Bathonian to Middle Callovian depending on the

specimens clearly differ from Choffatia (Subgrossouvria) recuperoi ammonite assemblages. Ammonites from the Buqu Formation in

(Gemmellaro) by having weak primary ribs and a compressed the Cuoriju section indicate the Middle to Late Bathonian in age

whorl section in the present collection. The outline of the whorl (Yin, 2005).

section is probably distorted due to compaction, but still differing Based on ammonite evidence, it is now recognized that the

from other species known in this genus. Choffatia sakutala Spath bivalve assemblages of the Yangshiping section represent an

occurs in the Middle Callovian Anceps Zone in Kachchh (Spath, ecological response to changes of depositional environment during

1928). Middle Jurassic times, and that the bivalve succession adds little to

the biostratigraphical framework, supposed from the Middle to

4. Conclusions Upper Jurassic of the region. The faunal succession in the

Yanshiping section reﬂects facies changes rather than any major

In general during the Middle Jurassic the marine depositional biostratigraphical differences (Fig. 13).

environment progressively deepened and siliciclastic sediment The Xueshan Formation overlying the Suowa Formation in the

input decreased from the east from the Yangshiping area to the northern Qiangtang is known to yield Early Cretaceous palynoﬂoras,

Fig. 13. Jurassic bivalve succession in the Yangshiping section and ammonite levels in the Cuoriju and Changhonghe sections in northern Qiangtang.

J. Yin / Proceedings of the Geologists’ Association 127 (2016) 247–265 263

Ammonoidea. The University of Kansas Press and Geological Society of America,

petriﬁed woods and non-marine bivalves (Yin et al., 1993; Tan et al.,

New York, NY/Lawrence, KS, L1–L475.

2003, 2004; Li and Batten, 2004; Zhu et al., 2012; Zeng et al., 2012b).

Bai, S.H., 1989. Recent achievement of marine Jurassic in southern Qinghai Province.

It is proposed that this indicates a hiatus across the entire northern Geological Review 35, 529–536.

Bardhan, S., Sardar, S., Jana, S.K., 2002. The Middle Jurassic Kheraiceras SPATH 1924

Qiangtang region spanning at least the entire Upper Jurassic

from the Indian Subcontinent. Abhandlungen der Geologischen Bundesanstalt

between the marine Suowa and non-marine Xueshan formations.

57, 265–277.

It suggests that the Jurassic Tanggula ocean (= northeastern Blake, J.F., 1907. A Monograph of the Fauna of the Cornbrash. Monograph of

Palaeontographical Society London, Cambridge University Press 138 pp.

Qiangtang area of Wang, 1985) disappeared as early as the Middle

Bonarelli, G., 1894. Hecticoceras, novum genus Ammonidarum. Bolletino della

Jurassic (the Callovian Stage), not as has been stated by Wang (1985),

Societa Malacolica Italiana 18 (1893), 73–104.

in the Late Jurassic. Buckman, S.S., 1909–1930. Type Ammonites. Weldon and Wesley, Thame and

With the discovery of hydrocarbon reservoir rocks in the Suowa London 7 vols., 790 pls.

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and Xiali formations (Wang et al., 2001, 2004, 2009; Tan et al.,

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2002; Du et al., 2003; Li et al., 2005; Sun et al., 2013) the age of the 114–130.

Suowa Formation also becomes highly signiﬁcant. The study of Callomon, J.H., 1993. On Perisphinctes congener Waagen, 1875, and the age of the

Patcham Limestone in the Middle Jurassic of Jumara, Kutch, India. Geologischen

Jurassic ammonite assemblages of the northern Qiangtang are

Bla¨tter fu¨ r Nordostbayern 43, 227–246.

signiﬁcantly advanced by the ammonite fauna of Kachchh and its

Callomon, J.H., Dietl, G., Niederhon, J.H., 1992. On the true stratigraphic position of

biostratigraphical framework (Spath, 1928; Callomon, 1993; Macrocephalites macrocephalus (Schlotheim, 1813) and the nomenclature of the

standard Middle Jurassic Macrocephalus Zone. Beitrcep zur Naturkunde B185,

Pandey and Callomon, 1995; Bardhan et al., 2002; Jana et al.,

65 pp.

2005; Roy et al., 2007; Jain, 2014; Jain and Desai, 2014). This

Cariou, E., Krishna, J., 1988. The Tethyan Reineckeiinae of Kachchh and Jaisalmer

enables the possibility of the discussing the Tibetan ammonite (West India): systematic, biostratigraphic and biogeographic implications.

Palaeontographica A 203, 149–170.

assemblage at the biochron level. The ammonite succession from

Cariou, E., Hantzpergue, P., 1997. Biostratigraphie du Jurassique ouest–Europe´en et

the Middle Bathonian to Early Middle Callovian in the Chon-

me´diterrane´en. Bulletin du Centre de Recherches Elf Exploration Production

ghonghe section has been established and includes several Me´moire 17, 423 pp.

Collignon, M., 1958. Atlas des fossiles caracte´ristiques de Madagascar. Fascicule 2

hiatuses. Late Jurassic ammonites are so far absent due to the

(Bathonien, Callovien). Service Ge´ologique de Tananarive, 1–33 pls.

large-scale destruction of the carbonate platform and shelf

Cuvier, G., 1795. Second Me´moire sur l’organisation et les rapports des animaux a`

habitats attributed to a regression that must have occurred in sang blanc, dans lequel on traite de la structure des Mollusques et de leur

post-Middle Callovian times in northern Qiangtang. division en ordre, lu a` la socie´te´ d’Histoire Naturelle de Paris, le 11 prairial an

troisie`me. Magazin Encyclope´dique, ou Journal des Sciences, des Lettres et des

The ammonite fauna discussed here is characterized by low

Arts 1795 [1. anne´e] 2, 433–449.

diversity and is mainly composed of species formerly considered

Dietl, G., 1982. Das wirkliche Fundniveau von Ammonites aspidoides Oppel (Ammo-

endemic to Kachchh and Madagascar, such as Eucycloceras cf. noidea, Mittl. Jura) am locus typicus. Stuttgarter Beitra¨ge zur Naturkunde B87,

1–27.

cogginbrowni Spath, Nothocephalites asaphus Spath [m], Nothoce-

Donovan, D.T., Callomon, J.H., Howarth, M.K., 1981. Classiﬁcation of the Jurassic

phalites semilaevis (Waagen) [M], and Choffatia cf. sakutala Spath.

Ammonitina. In: House, M.R., Senior, J.R. (Eds.), The Ammonoidea. Systematic

Other species are widespread in Europe (Italy, Germany, and Association, Special Volume, 18, 101–155.

Douville´, H., 1890. Sur la classiﬁcation des Ce´ratites de la Craie. Bulletin de la Societe

England) and also occur in Kachchh and Madagascar, including

Geologique de France (series 3) 18, 275–292.

Macrocephalites compressus (Quenstedt), Choffatia (Subgrossouvria)

Du, B., Tan, F., Wang, J., Wang, X., 2003. Discovery of the largest asphalt veins in

recuperoi (Gemmellaro) and Macrocephalites (Macrocephalites) Qiangtang Basin and its signiﬁcance. Sedimentary Geology and Tethyan Geolo-

gy 1, 69–74.

madagascariensis Lemoine. The Middle Bathonian to Middle

Fischer, P., 1882. Manuel de conchyliologie et de pale´ontologie. F. Savy, Paris 1369

Callovian ammonites from the northern Qiangtang area suggest

p., 23 pls.

that ammonite faunal provincialism was less pronounced and that Elmi, S., 1967. Le Lias supe´rieur et le Jurassique moyen de l’Arde´che. Documents des

Laboratoires de Ge´ologie de la Faculte´ des Sciences de Lyon 41, 376 p.

exchange between the east Tethyan and Indo-Malgach provinces

Enay, R., 2009. Les faunes d’ammonites de l’Oxfordien au Tithonien et la

was stronger than previously thought.

Biostratigraphie des Spiti-shales (Callovian superieur-Tithonien) de Thak-

khola, Nepal Central. Documents des Laboratoires de Geologie Lyon 166, 351

Acknowledgements pp.

Enay, R., Cariou, E., 1997. Ammonite fauna and palaeobiogeography of the Himala-

yan belt during the Jurassic: Initiation of a Late Jurassic austral ammonite fauna.

I wish to acknowledge John Callomon who ﬁrst drew my Palaeogeography, Palaeoclimatology, Palaeoecology 134, 1–38.

Enay, R., Cariou, E., 1999. Jurassic ammonite faunas and their bearing on the

attention to ammonite research in Tibet. I am grateful for the help

palaeobiogeography of the Himalayan belt. Journal of Asian Earth Sciences

given to me by him in the past. The results here have advanced

17, 829–848.

signiﬁcantly the understanding of the collection made by Zeng and Fan, H., Yang, J., Zhang, P., 1988. Late Jurassic strata in northern Tibet. Journal of

Stratigraphy 12, 66–70 (in Chinese).

his colleagues (Chengdu) for which I am grateful for access. I am

Fang, D., Liang, D., 2000. New advances in the research on the Upper Jurassic in the

indebted to Franz Fu¨ rsich for his constructive suggestions and

Middle of the North Qiangtang Basin. Journal of Stratigraphy 24, 163–167 (in

improvement in the English of the manuscript. I am also indebted Chinese).

to Robert Chandler and John Cope for their help in the course of Fang, D., Pang, Q., Zhang, Y., Miao, H., 2000. Discussion on the stratigraphic

classiﬁcation of the upper Jurassic of Donghu Region in Qiangtang Basin. Journal

producing the manuscript. I would like to express my gratitude to

of Daqing Petroleum Institute 24, 15–18 (in Chinese).

two anonymous reviewers for their constructive comments and

Fang, D., Yun, J., LI, C., 2002. Discussion of the Xueshan Formation in the north of

remarks. This work has been ﬁnancially supported by the Project Qiangtang basin, Qinghai-Tibet Plateau. Journal of Stratigraphy 26 (1), 68–72

(in Chinese).

973-2012CB822001 from Ministry of Science and Technology of

Gemmellaro, G.G., 1873. Sopra i cefalopodi della zona con Stephanoceras macro-

China.

cephalum, Schloth. sp. della Rocca chi parra presso Calataﬁmi, provincia di

Trappani. Atti dell’Accademia Gioenia di Scienze Naturali 8, 165–202.

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