Chu centipede (Mecistocephalus chuensis) and Luqi Huang centipede (Mecistocephalus huangi) from China

NEWS - Species delimitation using Automatic Barcode Gap Discovery, Poisson Tree Processes, phylogenetic and morphological analyses revealed 10 species, including 2 new species, Chu centipede (Mecistocephalus chuensis Jiang & You, sp. nov.) and Luqi Huang centipede (Mecistocephalus huangi Jiang & You, sp. nov.).

Mecistocephalus Newport 1843 is the most diverse genus in Mecistocephalidae Bollman 1893 which includes almost 70% of mecistocephalid species. About 135 species have been officially reported distributed in tropical and subtropical Asia South Asia, Southeast Asia, East Asia with a small number from Africa, America and temperate regions.

The earliest species found in China is Mecistocephalus smithii Pocock 1895 from Ningbo, Zhejiang Province. Up to now 14 species have been reported in China, but research and knowledge in China are incomplete. Now researchers describe two new species from China and redescribe M. smithii.

Mecistocephalus chuensis is a species in the Mecistocephalidae with 49 leg pairs. Head length-to-width ratio 1.77, each side of clypeus with five or six smooth insulae, clypeal ratio (areolate part/non-areolate part) of 1.22, sensilla on plagulae absent, posterior 1/2 of cephalic pleurite bearing a group of setae, forcipular cerrus composed of two paramedian rows of setae, mandible with ~ 8 well-developed lamellae, and first lamella with seven teeth. Sternal sulcus furcated at an obtuse angle.

Mecistocephalus megittii Verhoeff 1937, Mecistocephalus stenoceps Chamberlin 1944, Mecistocephalus enigmus Chamberlin 1944 and Mecistocephalus chuensis are similar in the number of leg-bearing segments, sternal furcate sulcus and clypeus ratio. However, M. megittii has large teeth on the tarsungulum (vs. only small teeth at the base of the tarsungulum in M. chuensis) and one or two setae on each side of the clypeus (vs. 3 setae on each side of the clypeus in M. chuensis).

M. chuensis can be distinguished by the location of the setae and the presence or absence of teeth on the forcipular femur. The clypeus of Mecistocephalus stenoceps Chamberlin has three setae in a transverse row on each side further anteriorly (vs. no femoral teeth in M. chuensis and Mecistocephalus enigmus).

Mecistocephalus huangi is a species in Mecistocephalidae with 49 leg pairs. Head length-to-width ratio 2, each side of clypeus with two or three smooth insulae, clypeal ratio (areolate part/ non-areolate part) ~ 1, plagulae without sensilla, posterior 1/2 of cephalic pleurite bearing a group of setae, mandible with ~ 6 well-developed lamellae and first lamella with ~ 6 teeth. Sternal sulcus furcated at an obtuse angle. Metasternite trapezoid and with a pillow-like protrusion.

The new species resembles Mecistocephalus lanzai Matic & Dărăbanțu (1969) in the furcated sternal sulcus, three pairs of setae on the clypeus and a group of setae located exclusively on the posterior 1/2 of the cephalic pleurite. However, a distinguishing feature of M. lanzai is the absence of basal teeth on the tarsungulum.

M. huangi shows clear morphological similarities to M. chuensis. However, it has five to six smooth insulae on the first clypeus and cushion-like protuberances on the metasternites that are common to the paratype and nontype material of M. huangi. Both were found to form two distinct, though closely related, clades in phylogenetic analysis.

Original research

Pan Y-Y, Fan J-B, You C-X, Jiang C (2024). Identification of two new species of Mecistocephalus (Chilopoda, Geophilomorpha, Mecistocephalidae) from southern China and the re-description of Mecistocephalus smithii Pocock, 1895. ZooKeys 1218: 1-23, DOI:10.3897/zookeys.1218.130709

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