Sinocranum Chu & Li, 2023

Chu, Chang, Li, Shuqiang, Yao, Yanbin & Yao, Zhiyuan, 2023, One new genus and four new species of Liocranidae Simon, 1897 (Arachnida, Araneae) from China and Vietnam, ZooKeys 1181, pp. 219-240 : 219

Genus Sinocranum Chu & Li gen. nov.

Type species.

Sinocranum menghai Chu & Li, sp. nov.

Composition.

Monotypic.

Etymology.

The generic name is a combination of " sino ", referring to the China, and " cranum " as part of the genus Liocranum . Gender is neuter.

Diagnosis.

The new genus resembles Agroeca Westring, 1861 by having a similar tegular lobe (Fig. 3A-C ) in the male and similar long copulatory ducts (Fig. 4B ) in the female. Males can be distinguished by the embolus originating retrolaterally (Fig. 3C ; vs. embolus originating prolaterally in Agroeca ), by the conductor strongly sclerotized (Fig. 3A-F ; vs. conductor membranous in Agroeca ), and by the palp with ventral tibial apophysis and dorsal tibial apophysis (Fig. 3A-C ; absent in Agroeca ). Females can be distinguished by the epigynal plate without hoods (Fig. 4A ; present in Agroeca ), by the vulva with glandular appendages (Fig. 4B ; absent in Agroeca ), and by the fertilization ducts pointing anteriorly (Fig. 4B ; vs. fertilization ducts pointing laterally in Agroeca ).

Sinocranum gen. nov. shares several synapomorphies with the members of the genus Agroeca . The most important of these is tegular lobe with a distinct curved prolaterally in ventral view. Similarities can be observed in the general structure of the male palp (shape of cymbium and tibia; position of conductor and tegular apophysis). The distribution of the eyes is also similar to that in Agroeca . However, despite these similarities, there are still significant differences between Sinocranum and Agroeca (refer to above genus diagnosis for details). The new genus Sinocranum with two most obvious morphological characteristics: male palp with ventral tibial apophysis, retrolateral tibial apophysis and dorsal tibial apophysis; female copulatory ducts bifurcate from subdistally to distally. These two characteristics are different from all other existing genera in the family. Therefore, based on the above morphological data, we suggest establishing a new genus Sinocranum to accommodate S. menghai sp. nov.

Description.

Small to medium-sized spiders (total body length 7.89-10.70; Figs 5A-D , 11A ). Eight eyes in two rows; PER longer than AER, AER recurved, PER almost straight in dorsal view. AME separated by less than their diameter, closer to ALE; PME separated by almost twice their diameter, about as far from ALE; Distance between AME and PME longer than that between ALE and PLE; ALE and PLE separated by about their diameter. Carapace reddish-brown with lighter heart region, laterally with dark stripes, submarginally with lighter patches, marginally dark, with white hairs; fovea reddish-brown. Chelicerae reddish-brown, with three promarginal and two retromarginal teeth. Endites yellowish- to reddish-brown, longer than wide, narrower in middle, subapically with semicircular membranous area and dense scopula. Labium reddish-brown with lighter distal lip. Sternum reddish-brown. Legs yellowish-brown, lateral tarsi and metatarsi I-II with dense scopulae. Leg spination: femora with 2-4 pairs of lateral spines and 3 dorsal spines; tibiae with 0-3 pairs of lateral spines, 0-3 dorsal spines and 3 pairs of ventral spines; metatarsi with 0-4 pairs of lateral spines, 0-1 dorsal spine and 2 ventral spines or 1-3 pairs of ventral spines. Leg formula: 4123. Dorsal opisthosoma yellowish, median field with dark bands, laterally with reddish-brown stripes and dark patches. Lateral and ventral opisthosoma yellowish with dark spots and dark ring around spinnerets. Spinnerets yellowish.

Palpal (Fig. 3A-F ) tibia with three apophyses; ventral tibial apophysis arc-shaped; retrolateral tibial apophysis long, with blunt and thin sheet-shaped tip; dorsal tibial apophysis straight, with wide base and narrow tip deviating from the direction of palp. Bulb longer than wide, tegular lobe curved prolaterally. Tegulum with distinct, U-shaped sperm duct subcentrally; subtegulum strongly sclerotized, clearly visible in ventral view. Embolus originating retrolaterally, long and filiform, connected to conductor. Conductor strongly sclerotized, originating distally. Tegular apophysis originating subdistally.

Epigynal field (Fig. 4A, B ) with two large spots; epigynal plate sclerotized. Copulatory openings hidden under epigynal plate. Copulatory ducts long and curved. Glandular appendages globular, originating subdistally to copulatory ducts. Spermathecae large, separated by less than half of their diameter. Fertilization ducts almost as long as diameter of spermathecae, close to each other distally, pointing anteriorly.

Distribution.

China (Yunnan; Fig. 12 ).

Figures

Figure 3. Sinocranum menghai sp. nov., holotype male palp (A-C), conductor and embolus (D-F) A prolateral view B ventral view C retrolateral view D frontal view E retrolateral view F dorsal view. Abbreviations: C = conductor, DTA = dorsal tibial apophysis, E = embolus, EA = embolic apophysis, RTA = retrolateral tibial apophysis, SD = sperm duct, ST = subtegulum, TA = tegular apophysis, TL = tegular lobe, VTA = ventral tibial apophysis. Scale bars: 0.50 mm (A-C); 0.20 mm (D-F).

Figure 4. Sinocranum menghai sp. nov., paratype female (A, B) A epigyne, ventral view B vulva, dorsal view. Abbreviations: CD = copulatory duct, CO = copulatory opening, FD = fertilization duct, GA = glandular appendage, SP = spermathecae. Scale bars: 0.20 mm.

Figure 5. Sinocranum menghai sp. nov., holotype male (A, B) and paratype female (C, D) A-D habitus A dorsal view B ventral view C dorsal view D ventral view. Scale bars: 2.00 mm.

Figure 11. Ocular areas and tapeta of liocranids. A Sinocranum menghai sp. nov. B Xantharia baizilongi sp. nov., inset shows oblique tapetum of PME C X. cucphuong sp. nov. Scale bars: 0.50 mm (A); 0.20 mm (B, C).

Figure 12. New distribution records of liocranid spiders from China and Vietnam 1 Koppe ninger sp. nov. 2 Sinocranum menghai sp. nov. 3 Xantharia baizilongi sp. nov. 4 X. cucphuong sp. nov.