We describe Scolopocryptops longipes sp. nov., a new troglobitic scolopocryptopine centipede species from a karstic area in southern China. The species was found in Shuiba Cave of Libo County, Guizhou Province. The cephalic plate wider than long, with complete margination along the lateral margin of cephalic plate; TT6–19 with complete paramedian sutures; tibia, tarsus 1 and tarsus 2 of leg 22 each with one spur; prefemur and femur of ultimate legs glabrous, tibia and tarsi with dense bristles. S. longipes is the second troglobitic scolopocryptopine in China and the fourth in the world described thus far.

Otostigmus (Otostigmus) xizangensis n. sp., a new species of subgenus Otostigmus Porat, 1876 from Xizang, China, is described and illustrated. The new species is diagnosed as follows: antennae 17–19 articles (mainly 19), basal antennal articles cylindrical; forcipular tooth-plate with 4 teeth; tergites (5) 6–20 with complete paramedian sutures; well-developed lateral margination on tergites (6) 9–21; ultimate leg prefemora with four rows of spines, leg 20 with one tarsal spur. The coxopleural process of O. (O.) xizangensis n. sp. exhibits remarkable sexual dimorphism, being long and curved in females, short and straight in males.

A new species, Scorpiops ingens sp. n., from Xizang, is described and illustrated. Scorpiops ingens sp. n. is characterized by yellow-brown color, large size (length of adults above 70.0 mm), small and dense granules on tegument, a pair of small median eyes, 17 external trichobothria (5 eb, 2 esb, 2 em, 4 est, 4 et), and 7 or 8 (usually 7) ventral trichobothria in the pedipalp patella, chela with a length/width ratio average of 2.2 in males and females, pedipalp chela fingers on adult females and males scalloped, pectinal teeth count 6–8, pectinal fulcra absent. With the description of this new species, the number of known species of Scorpiops from China is raised to 12. An updated identification key to Scorpiops from China is presented.

The morphological and functional evolution of appendages has played a key role in the diversification of arthropods. While the ancestral arthropod appendage is held to be polyramous, terrestriality is associated with the reduction or loss of appendage rami, which may obscure the homology of different appendage derivatives. Proxies for appendage homology have included surveys of cross-reactive antibodies for wing markers like Nubbin/PDM, which have suggested that the abdominal appendages of arachnids (e.g., book lungs, tracheal tubules) are derived from ancestral gills (epipods). Here, we discovered a rare case of inferred homeosis in a scorpion in which the bilobed genital opercula and the pectines are transformed to walking legs, and an abnormal sternite shows a book lung close to an everted structure comparable to the morphology of some Palaeozoic scorpion fossils. The observed morphology is consistent with abnormal expression of homeotic genes during embryonic development. The phenotype of this abnormal specimen suggests that the genital opercula, the pectines, and parts of the book lung may be derived from the telopodite of abdominal appendages rather than from epipods. This interpretation contradicts the “ancestral gill” hypothesis but reconciles features of the Palaeozoic scorpion fossil record with the embryology of modern scorpions.

Mesobuthus martensii, a famous and important Traditional Chinese Medicine has a long medical history and unique functions. It is the first scorpion species whose whole genome was sequenced worldwide. In addition, it is the most widespread and infamous poisonous animal in northern China with complex habitats. It possesses several kinds of toxins that can regulate different ion channels and serve as crucial natural drug resources. Extensive and in-depth studies have been performed on the structures and functions of toxins of M. martensii. In this research, we compared the morphology of M. martensii populations from different localities and calculated the COI genetic distance to determine intraspecific variations. Transcriptome sequencing by RNA-sequencing of the venom glands of M. martensii from ten localities and M. eupeus from one locality was analyzed. The results revealed intraspecific variation in the expression of sodium channel toxin genes, potassium channel toxin genes, calcium channel toxin genes, chloride channel toxin genes, and defensin genes that could be related to the habitats in which these populations are distributed, except the genetic relationships. However, it is not the same in different toxin families. M. martensii and M. eupeus exhibit sexual dimorphism under the expression of toxin genes, which also vary in different toxin families. The following order was recorded in the difference of expression of sodium channel toxin genes: interspecific difference; differences among different populations of the same species; differences between sexes in the same population, whereas the order in the difference of expression of potassium channel toxin genes was interspecific difference; differences between both sexes of same populations; differences among the same sex in different populations of the same species. In addition, there existed fewer expressed genes of calcium channel toxins, chloride channel toxins, and defensins (no more than four members in each family), and their expression differences were not distinct. Interestingly, the expression of two calcium channel toxin genes showed a preference for males and certain populations. We found a difference in the expression of sodium channel toxin genes, potassium channel toxin genes, and chloride channel toxin genes between M. martensii and M. eupeus. In most cases, the expression of one member of the toxin gene clusters distributed in series on the genome were close in different populations and genders, and the members of most clusters expressed in same population and gender tended to be the different. Twenty-one toxin genes were found with the MS/MS identification evidence of M. martensii venom. Since scorpions were not subjected to electrical stimulation or other special treatments before conducting the transcriptome extraction experiment, the results suggested the presence of intraspecific variation and sexual dimorphism of toxin components which revealed the expression characteristics of toxin and defensin genes in M. martensii. We believe this study will promote further in-depth research and use of scorpions and their toxin resources, which in turn will be helpful in standardizing the identification and medical applications of Quanxie in traditional Chinese medicine.