A taxonomical revision of ‘Dongfangaspis qujingensis’ from the Lower Devonian of Qujing, Yunnan Province

doi:10.19615/j.cnki.2096-9899.240321

Abstract

Abstract:

The affinity of ‘Dongfangaspis qujingensis’, initially assigned to Dongfangaspis but later to Laxaspis, has long been controversial. However, the taxonomical revision raises a new problem of junior homonym since the type species of Laxaspis is L. qujingensis. Here, we describe some new materials of ‘Dongfangaspis qujingensis’ and Damaspis vartus from the Xishancun Formation (early Lochkovian, Early Devonian) in Qujing, Yunnan Province. ‘Dongfangaspis qujingensis’ strikingly resembles Damaspis vartus in the slightly longer headshield, bifurcated ends of the lateral transverse canals, unconnected V-shaped posterior supraorbital canals, and at least seven pairs of lateral transverse canals issuing from the lateral dorsal canal. These similarities indicate that ‘D. qujingensis’ is more suggestive of Damaspis than Dongfangaspis and Laxaspis. Therefore, we propose to remove ‘Dongfangaspis qujingensis’ from Laxaspis to Damaspis. The new specimens of Damaspis vartus reveal five long lateral transverse canals on the right side, corroborating that the asymmetric sensory canal system in the holotype is the intraspecific variation.

Key words: Qujing, Yunnan, Lower Devonian, Xishancun Formation, Damaspis, Polybranchiaspidae, Galeaspids

摘要：

“曲靖东方鱼” (‘Dongfangaspis qujingensis’)的归属长期以来存在争议，其最初被归入东方鱼属(Dongfangaspis), 之后被归入宽甲鱼属(Laxaspis)。然而，由于宽甲鱼属模式种为曲靖宽甲鱼(Laxaspis qujingensis), 这一分类学厘定又引起异物同名的问题。描述了来自云南曲靖早泥盆世洛赫考夫期西山村组的 “曲靖东方鱼” 和变异坝鱼(Damaspis vartus)的新材料。“曲靖东方鱼” 在头甲长略大于宽，侧横管末端呈二分叉，V字型后眶上管不汇合，以及至少7条侧横管从侧背管发出等方面与变异坝鱼高度相似。这些相似之处表明，相较于宽甲鱼属和东方鱼属, “曲靖东方鱼” 更接近坝鱼属。因此提出将 “曲靖东方鱼” 从宽甲鱼属中移除，归入坝鱼属。新标本表明变异坝鱼多出来第5对长的侧横管是该种的一个鉴别特征，而正型标本所呈现的非对称感觉管系统应为种内变异所造成。

关键词: 云南曲靖, 下泥盆统, 西山村组, 盔甲鱼类, 多鳃鱼科, 坝鱼属

CLC Number:

Q915.861

SHAN Xian-Ren, ZHU Min, LI Qiang, GAI Zhi-Kun. A taxonomical revision of ‘Dongfangaspis qujingensis’ from the Lower Devonian of Qujing, Yunnan Province. Vertebrata Palasiatica, 2024, 62(2): 85-98.

山显任, 朱敏, 李强, 盖志琨. 2024, 62(2): 85-98, 云南曲靖下泥盆统“曲靖东方鱼”的分类学厘定. 古脊椎动物学报.

Figures/Tables 8

Table 1 Measurements and comparisons of Damaspis (mm)

Items	D. vartus				D.qujingensis
	IVPP V6259.				IVPP V5017.
	1	4	5	6	2	3	4
Maximum length of the headshield	93.4	102.4	−	103.4	115.2	117.7	−
Maximum width of the headshield	85.5	97.2	106.2	−	98.4	102.8	110.5
Length of the headshield in midline	69.0	−	−	−	92.5	99.5	−
Long axis of orbital openings	5.4	6.0	−	5.6	7.7	8.2	8.4
Distance between orbital openings	32.8	31.2	−	37.4	45.6	47.0	48.7
Long axis of median dorsal opening	18.8	17.0	−	17.7	19.6	23.2	22.8
Short axis of median dorsal opening	9.8	8.4	−	8.5	12.2	13.3	13.6
Diameter of pineal opening	1.3	0.9	1.2	1.1	−	−	2.0

Fig. 1 Nearly complete headshields of Damaspis qujingensis (IVPP V5017.2-4) A, B. IVPP V5017.2 (A), V5017.3 (B), in dorsal views; C, D. V5017.4, in dorsal (C) and ventral (D) views; scale bars equal 10 mm Abbreviations: br. region. branchial region; dcm. dorsal commissure; ic. inner cornual process;ifc. infraorbital canal; ldc. lateral dorsal canal; ltc. lateral transverse canal; md.o. median dorsal opening;md.r. median dorsal ridge; md.s. median dorsal spine; obr.c. oralobranchial chamber; orb. orbital opening;pi. pineal opening; soc1. anterior supraorbital canal; soc2. posterior supraorbital canal; vr. ventral rim

Fig. 2 The sensory canal system of Damaspis qujingensis (Holotype and V5017.5−7) A. an incomplete headshield, GMC V1735, holotype, in ventral view; B−D. three fragmentary headshields, IVPP V5017.5 (B), V5017.6 (C), V5017.7 (D), in ventral views; scale bars equal 10 mm For abbreviations see Fig. 1

Fig. 3 Restoration of Damaspis qujingensis sp. nov. in dorsal (A) and ventral (B) views Scale bar equals 10 mm. For abbreviations see Fig. 1 plus br.f. branchial fossa

Fig. 4 Photographs of Damaspis vartus (IVPP V6259.4) from Qujing, Yunnan An incomplete headshield, IVPP V6259.4a, in ventral view (A) and its internal mould, V6259.4b, in dorsal view (B) Scale bar equals 10 mm. For abbreviations see Fig. 1

Fig. 5 Photographs of Damaspis vartus (IVPP V6259.5, 6) from Qujing, Yunnan A, B. an incomplete headshield, IVPP V6259.5a, in dorsal view (A) and its external mould, V6259.5b, in ventral view (B); C. an incomplete headshield, V6259.6, in dorsal view; scale bars equal 10 mm For abbreviations see Figs. 1, 3

Fig. 6 Restoration of Damaspis vartus in dorsal (A) and ventral (B) views Scale bar equals 10 mm. For abbreviations see Figs. 1, 3

Fig. 7 Restoration of Damaspis, Dongfangaspis, and Laxaspis, showing their diagnostic differences A−D. Damaspis vartus, D. qujingensis, Dongfangaspis major, and Laxaspis qujingensis,respectively in dorsal view, not to scale; the left half part of the headshield shows the differences in the sensory canal system, the right half part of the headshield shows the differences in branchial fossae

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