Ceratognathini gen. et sp. indet. 1, 1843
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publication ID |
https://dx.doi.org/10.3897/evolsyst.7.104597 |
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publication LSID |
lsid:zoobank.org:pub:921F39DA-40BB-4796-8E36-2194D1E9A138 |
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persistent identifier |
https://treatment.plazi.org/id/2DE65E55-8364-5499-B38E-F5BB21C98675 |
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treatment provided by |
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scientific name |
Ceratognathini gen. et sp. indet. 1 |
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Ceratognathini gen. et sp. indet. 1 View in CoL
Figs 1D View Figure 1 , 11 View Figure 11 , 12. View Figure 12
Material examined.
1 ex. (sex undertemined), a complete adult preserved in a narrowly elongate yellowish amber, approximately 17.1 mm × 6.9 mm × 3.8 mm in size (Fig. 1D View Figure 1 ); specimen accession number SEHU-0000121207, housed in HUM. The specimen is poorly preserved. The body is noticeably deformed and squashed, although the amber is transparent without pigmentation (Fig. 11 View Figure 11 ). Due to the heavily modified condition of the specimen, it was impossible to make a detailed comparison or accurate measurements of each body part; consequently, only the body length was measured.
Locality and horizon.
Hukawng Valley (26°20'N, 96°36'E), Kachin State, northern Myanmar; unnamed horizon, mid-Cretaceous, Upper Albian to Lower Cenomanian.
Description.
Details of ventral side not well observable. Body (Fig. 11 View Figure 11 ) small, narrowly elongate, subparallel sided, 2.78 mm long (measured from anterior margin of head to apex of elytra). Color uniformly dark brown. Dorsal and ventral surfaces heavily modified, probably due to the fossilization process, without neither setae nor modified scales. Head (Fig. 12A View Figure 12 ) very small, transverse. Antenna (Fig. 12B-D View Figure 12 ) seemingly 10-segmented (provisional interpretation shown in Fig. 12B, D View Figure 12 ) with three-segmented small club (Fig. 3A View Figure 3 ). Pronotum (Fig. 11A View Figure 11 ) slightly wider than long, with arcuate lateral margins. Procoxal cavities (Fig. 11B View Figure 11 ) probably subcontiguous. Elytra (Fig. 11A View Figure 11 ) complete, narrowly elongate, nearly subparallel-sided. Legs (Figs 11 View Figure 11 , 12B, E-G View Figure 12 ) relatively short. Protibia (Figs 11 View Figure 11 , 12B, E, F View Figure 12 ) slender, flattened, moderately curved, gradually widened apically, with one large apical spur; external margin armed with three strong teeth in apical half, i.e., apical tooth (at) and mid-dorsal teeth 1-2 (mdt1 - 2) (sensu Holloway 2007: fig. 1), with about 5 short and subcontiguous tooth-like spines before mid-dorsal tooth 1, 5 between mid-dorsal tooth 1 and mid-dorsal tooth 2, and finally 5 between apical tooth and mid-dorsal tooth 2 (Fig. 12B View Figure 12 , arrow). All tarsi (Fig. 12B, E, G View Figure 12 ) 5-segmented, each slender and rather long. Arolium (Fig. 12E, G View Figure 12 , ra, sa) developed, with short rod, bearing 2 bristles on its apex. Abdomen not well observable. Genitalia not visible.
Systematic placement and comparison.
It is challenging to assign the new material to Lucanidae unambiguously based on the available morphology. I could not observe the details of the abdomen to clarify if it has five-free ventrites or clear antennal segmentation. These are important diagnostic features that define the family. However, it is best placed in Lucanidae , more specifically the tribe Ceratognathini , based on the general habitus, 5-5-5 tarsal formula, antennae appearing 10-segmented (if correct) with three-segmented apical club, and the structures of legs including protibial outer edges with well-developed arolium between the pretarsal claws (e.g., Ratcliffe 2002; Holloway 2007; Reid 2019). The new specimen lacks modified scales and setae on the dorsal surface, as in Oncelytris and the two other Kachin amber ceratognathins recorded here. The extinct taxon is treated provisionally herein as " Ceratognathini gen. et sp. indet. 1" and can be differentiated from Cretognathus gen. nov. by having a much smaller head and antennal club, more slender tarsi, and different protibial edges (slightly different arrangement of subcontiguous tooth-like spines and much wider mid-dorsal teeth). Moreover, this new specimen does not seem to be congeneric with " Ceratognathini gen. et sp. indet. 2" by the distinctly smaller head and protibial morphology (shape, size, location, and number of the subequal tooth-like spines). Nevertheless, it is difficult to distinguish it from Oncelytris , due to the poor state of preservation of the fossil. In fact, the dorsal and ventral surfaces of " Ceratognathini gen. et sp. indet. 1" are greatly distorted, preventing the accuate observation of the head and elytra whether it possesses tubercles and protuberances on the dorsum or not (cf. Li Y-D et al. 2023). However, it is also noted that the protibiae of " Ceratognathini gen. et sp. indet. 1" is evidently arcuate, whereas those of Oncelytris are linear, suggesting that they may belong to different genera.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.