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古地理学报 ›› 2024, Vol. 26 ›› Issue (2): 387-400. doi: 10.7605/gdlxb.2024.02.023

• 生物古地理学及古生态学 • 上一篇    下一篇

新疆东准噶尔地区早泥盆世软舌螺的发现及其古生态和古地理意义*

黄烈斌1, 刘一龙2, 纵瑞文3, 高丹霞1, 申岑1   

  1. 1 昆明理工大学国土资源工程学院,云南昆明 650031;
    2 中国地质大学(武汉)地球科学学院,湖北武汉 430074;
    3 中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉 430074
  • 收稿日期:2023-08-01 修回日期:2023-09-22 出版日期:2024-04-01 发布日期:2024-04-03
  • 通讯作者: 申岑,女,1985年生,副教授,主要从事寒武纪磷酸盐化化石研究。E-mail: cshen@kmust.edu.cn。
  • 作者简介:黄烈斌,男,1998年生,硕士研究生,主要从事泥盆纪古生物学与地层学研究。E-mail: hliebin@163.com。
  • 基金资助:

    *云南省高层次人才培养支持计划“青年拔尖人才”专项和昆明理工大学分析测试基金(编号: 2022M20212101024)联合资助

Discovery of the Early Devonian hyoliths in East Junggar,Xinjiang and their palaeoecological and palaeogeographic significances

HUANG Liebin1, LIU Yilong2, ZONG Ruiwen3, GAO Danxia1, SHEN Cen1   

  1. 1 Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650031,China;
    2 School of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,China;
    3 State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences(Wuhan),Wuhan 430074,China
  • Received:2023-08-01 Revised:2023-09-22 Online:2024-04-01 Published:2024-04-03
  • Contact: SHEN Cen,born in 1985,is an associate professor. She is engaged in the research of Cambrian phosphatized fossils. E-mail: cshen@kmust.edu.cn.
  • About author:HUANG Liebin,born in 1998,is a master’s degree candidate. He is engaged in the study of Devonian palaeontology and stratigraphy. E-mail: hliebin@163.com.
  • Supported by:

    Co-fund by the top-notch young person under the “Ten thousand Talents Program” in Yunnan Province and Kunming University of Science and Technology Analysis Test Fund(No.2022M20212101024)

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摘要：

本文首次系统报道了来自中国新疆东准噶尔地区早泥盆世地层中的软舌螺化石,共计3属3种,分别为: 王氏富蕴螺Fuyunotheca wangi gen. et sp. nov.,施氏纵肋螺Costulatotheca schleigeri Earp,2019和奥氏螺未定种Ottomarites sp.。其中,王氏富蕴螺作为首次发现的新属种,典型特征为横切面呈扁椭圆形至亚三角形,背部膨胀,具有1条贯穿壳体的背中脊,腹部较平至微微凸起,壳体前1/3处具有横向成组的肋,整个壳体装饰着横向比纵向明显的细线。古生态学分析表明,王氏富蕴螺是一类生活在具有一定水动力的、富氧的正常浅海环境中的软舌螺。另外,笔者总结了包括新属种在内的目前所有报道过的整个泥盆纪产出的软舌螺的有效属种(不包括未定种和未定属),共计来自11个国家12个地区的14属66种,依据其古地理分布特征,认为泥盆纪的软舌螺主要分布在南半球的劳俄大陆和冈瓦纳大陆附近,其他地区仅零星出现。此次新疆东准噶尔地区软舌螺化石的发现, 不仅扩大了早泥盆世软舌螺类的古地理分布范围,同时为洲际间的地层对比提供了更多依据。

关键词: 软舌螺, 早泥盆世, 古生态, 古地理, 东准噶尔

Abstract:

The newly discovered hyoliths yielded from the Lower Devonian of East Junggar of Xinjiang,China,are documented herein for the first time,including three genera and three species: Fuyunotheca wangi gen. et sp. nov.,Costulatotheca schleigeri Earp,2019,and Ottomarites sp. As a new genus and species,F.wangi gen. et sp. nov. is mainly distinguished by typically oblate oval to subtriangular cross-section,swollen dorsal side with a pronounced median ridge,ventral side weakly convex. Surface sculpture prominent transverse striations and weakly longitudinal streaks on both dorsum and venter,and several sets of remarkable ribs parallel to the aperture in the anterior third of the conch. Palaeoecological analysis shows that F.wangi gen. et sp. nov. is a kind of orthothecids,which could live in a normal,oxygenated shallow-marine environment with certain degree of hydrodynamics. Furthermore,based on the Devonian hyoliths reported so far from all over the world,it has been recognized 14 genera and 66 species as valid from 12 areas in 11 countries(excluding indeterminate genera and species). Palaeogeographic distribution analysis shows that the Devonian hyoliths were mainly distributed in the southern hemisphere,that were positioned near the Laurussia and Gondwana,with a few species sporadically distributed in other plates or blocks. Newly discovered specimens of these early Devonian hyoliths not only expands the palaeogeographic distribution range of hyoliths during the Devonian period,but also provides new evidence for inter-continental biostratigraphic correlation.
Phylum uncertain
Class Hyolitha Marek, 1963
Order Orthothecida Marek, 1966
Family INDET.
Fuyunotheca gen. nov.
Type species Fuyunotheca wangi gen. et sp. nov.
Etymology Fuyun(Gr.)is derived from the Chinese Pinyin of the word “Fuyun” of Fuyun County,Altay Prefecture,Xinjiang. The theca(Gr.)means the capsule,membrane,sheath,and shell of organisms.
Diagnosis Orthothecids having straight and middle-sized conch with oblate oval to subtriangular cross-section;swollen dorsal side with a pronounced median ridge;ventral side flat to weakly convex. Aperture straight or almost straight. Apical part of shell blunt. No apical septa were found. Surface sculpture prominent transverse striations and weakly longitudinal streaks on both dorsum and venter,and several sets of remarkable ribs parallel to the aperture in anterior third of the conch near the apertural side. The separation distances between each set of transverse ribs gradually widen from the aperture to the apical end of the shell. Operculum is unknown.
Remarks The main difference between Hyolithida and Orthothecida is that the former has protrusions(lips)on the ventral side of aperture(Malinky and Racheboeuf,2010). The aperture of the new genus Fuyunotheca gen. nov. is straight and without protrusions,so it can be attributed to the order Orthothecida Marek,1966. According to the taxonomy of Orthothecidae Sysoev,1958 revised by Malinky(2009b),its venter is concave to flat,and sculpture of conch consists of longitudinal ridges or lines,without transverse ornamentation. The new genus has the similar conch with that of the family Orthothecidae,but differs from them in having a flat to slightly convex venter and sets of unique transverse ribs on the conch. The new genus is similar to Bolitheca Marek and Isaacson,1992 and Neobactrotheca Marek and Isaacson,1992 from the Middle Devonian Icla Formation of Bolivia. However,specimens of Bolitheca exhibit pronounced longitudinal ridges on the dorsum,the semi-elliptical cross-section,and rounded lateral ridges(Malinky and Racheboeuf,2011). Specimens of Neobactrotheca have many longitudinal ridges and no median ridges on the dorsum. Besides,the conch of Neobactrotheca differs from that of this new species by having elliptical cross-section and smooth transitions to the lateral ridges(Marek and Isaacson,1992). It is for this reason that we establish a new genus,belonging to the indeterminate family.
Fuyunotheca wangi gen. et sp. nov.
Fig.2
Etymology The species is named in honor of Wang Hongzhen,the famous paleontologist who described hyoliths from China for the first time.
Holotypoe One well-preserved dorsum of conch,specimen number: XJLD-001(Fig.2-A).
Paratype One well-preserved venter of conch,specimen number: XJLD-003(Fig.2-C).
Other materials Specimen registration number: XJLD-002,004—046. Venter or dorsum of 44 conchs with incomplete aperture or initial part.
Diagnosis As for the genus.
Description The conch is straight and conical,expanding gradually and evenly from the apex to the aperture, and the aperture is thickened(Fig.2-E,ta). The growth angle of the conch is about 9.90°. The length of the shell is about 41 mm,and the diameter of the aperture is about 9 mm. The dorsum passes through the oblate lateral ridge to the venter,and its cross-section has oblate oval to subtriangular shape(Fig.2-B2). There is a median ridge running through the conch(Fig.2-A,B1,dmr)in the middle of dorsum. There are slightly inclined surfaces on both sides of the ridge,and a longitudinal groove on the right slope(Fig.2-A,gr). Sets of remarkable ribs(Fig.2-A,2-C,2-D,tr)parallel to the aperture are distributed in the anterior third of the conch. There are five groups of ridges(Fig.2-A,tr1-tr5)which are made up of 2-5 transverse ridges in each group. The separation distances between each set of transverse ribs gradually widen from the aperture to the apical end of the shell. Surface of shell from the middle to the initial part covered with slight growth lines(Fig.2-F,tl). In addition,the conch is also decorated with weakly longitudinal lines(Fig.2-G,ll),that are most prominent next to aperture but become fainter in direction of apex. But longitudinal lines become thicker near the lateral ridge(Fig.2-G,tll),which may be caused by pressure applied to the shell during diagenes. Ventral side almost flat to very slightly convex,and bears the same ornamentation as the dorsum without a median ridge(Fig.2-C,2-D,tr). The apex is damaged to some extent,but it still can be seen that it is bluntly rounded in form,and no septa are visible.
Locality and horizon The first member of the Tuoranggekuduke Formation,Emsian Age,Lower Devonian,Chawukar area,Fuyun County,Altay Prefecture,Xinjiang.

Key words: Hyoliths, Lower Devonian, Palaeoecology, Palaeogeography, East Junggar

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