Trilacuna, Tong & Li, 2007

Wang, Ying, Tong, Yanfeng, Bian, Dongju & Li, Shuqiang, 2021, Two new species of the genus Trilacuna from Chongqing Municipality, China (Araneae, Oonopidae), Zootaxa 4927 (3), pp. 431-443 : 432-433

Key to species of the genus Trilacuna occurring in China

(females of T. angularis and T. cuneata unknown)

1 (0) Males............................................................................................. 2

- Females.......................................................................................... 15

2 (1) Epigastric region strongly elevated (e.g., Fig. 6H ; Liu et al. 2019: fig. 1E; Tong et al. 2019: figs 1I, 4I, 7I, 19I).......... 3

- Epigastric region flat................................................................................. 8

3 (2) Epigastric region with a long wedge-shaped scape (Liu et al. 2019: fig. 1E, F)................... T. cuneata Tong, 2019

- Epigastric region without the long wedge-shaped scape...................................................... 4

4 (1) Epigastric region with four long, very thick setae; sternum with many short, italic thick setae ( Tong et al. 2019: fig. 4E, H, I)....................................................................... T. datang Tong, Zhang & Li, 2019

- Without the above-mentioned characters.................................................................. 5

5 (4) Epigastric region with a cluster of densely short seta ( Fig. 6G ).................................. T. wenfeng sp. nov.

- Epigastric region without the above-mentioned character.................................................... 6

6 (5) Sternum with several grooves on posterior part ( Tong et al. 2019: fig. 1E)............. T. bawan Tong, Zhang & Li, 2019

- Sternum without grooves on posterior part................................................................ 7

7 (6) Sternum with a cluster of short setae on posterior part; embolus system with comb-like prolateral lobes ( Tong et al. 2019: figs 19E, 20B)............................................................... T. xinping Tong, Zhang & Li, 2019

- Sternum without cluster of short setae on posterior part; embolus system without comb-like prolateral lobes, but with rows of lobes in basal ventral groove and a large distal plate ( Tong et al. 2019: figs 7E, 8C)..... T. fugong Tong, Zhang & Li, 2019

8 (2) Embolus system with two very long, strongly curved outgrowths ( Tong et al. 2018: fig. 2C, D)................................................................................................. T. simianshan Tong & Li, 2018

- Embolus system without the above-mentioned character..................................................... 9

9 (8) Palpal tibia with numerous, very long, penniform setae on prolateral surface and two long, strong setae on retrolateral surface; posterior part of sternum with two elevated ridges, each covered with a row of short, strong setae ( Tong et al. 2018: figs 6E, 7C, D)....................................................................... T. songyuae Tong & Li, 2018

- Without the above-mentioned characters................................................................. 10

10 (9) Sternum with many rows of small ridges on posterior area ( Tong et al. 2019: figs 13E, 16E)........................ 11

- Sternum without small ridges on posterior area........................................................... 12

11 (10) Embolus system with four long, finger-like lobes and two distal broad lobes prolaterally ( Tong et al. 2019: fig. 17B)............................................................................... T. wuhe Tong, Zhang & Li, 2019

- Embolus system with two narrow, blade-like lobes prolaterally ( Tong et al. 2019: fig. 14B)................................................................................................ T. longling Tong, Zhang & Li, 2019

12 (10) Endites distally slightly branched; embolus system with three long, tooth-like lobes prolaterally ( Tong et al. 2019: figs 10E, 11B, D)............................................................... T. gongshan Tong, Zhang & Li, 2019

- Endites distally strongly branched; embolus system without three long, tooth-like lobes prolaterally................. 13

13 (12) Embolus system with a broad sickle-shaped branch prolaterally ( Figs 2C , 3E )....................... T. difeng sp. nov.

- Embolus system without a broad sickle-shaped branch prolaterally............................................ 14

14 (13) Base of embolus system strongly bulged prolaterally ( Tong & Li 2007: fig. 15)............. T. angularis Tong & Li, 2007

- Base of embolus system not bulged ( Tong & Li 2007: fig. 9)............................. T. rastrum Tong & Li, 2007

15 (1) Surface of sternum strongly rugose ( Tong et al. 2019: fig. 6E)...................... T. datang Tong, Zhang & Li, 2019

- Surface of sternum not strongly rugose.................................................................. 16

16 (15) Surface of sternum reticulated (e.g., Fig. 4D ; Tong et al. 2018: figs 5E, 10E).................................... 17

- Surface of sternum smooth, or slightly rugose on middle part................................................ 19

17 (16) Middle part of posterior margin of epigastric scutum strongly extended posteriorly; endogyne with a very long, nearly coneshaped structure ( Tong et al. 2018: figs 5H, I)..................................... T. simianshan Tong & Li, 2018

- Posterior margin of epigastric scutum smoothly curved, not strongly extended posteriorly; endogyne with a small globular shaped structure (e.g., Fig. 5A, B ; Tong et al. 2018: figs 10H, I).............................................. 18

18 (17) Epigastric region with a pair of large dark knob; globular structure of endogyne very small ( Tong et al. 2018: fig. 10H, I).............................................................................. T. songyuae Tong & Li, 2018

- Epigastric region without large dark knob; globular structure of endogyne large ( Fig. 5A, B )........... T. difeng sp. nov.

19 (16) Surface of sternum slightly rugose on middle part ( Tong et al. 2019: figs 15E, 18E).............................. 20

- Surface of sternum smooth........................................................................... 21

20 (19) Middle part of anterior margin of postgastric scutum smooth ( Tong et al. 2019: fig. 24I)................................................................................................... T. longling Tong, Zhang & Li, 2019

- Middle part of anterior margin of postgastric scutum arch-shaped ( Tong et al. 2019: fig. 25A)................................................................................................. T. wuhe Tong, Zhang & Li, 2019

21 (19) Endogyne with a posterior horseshoe-shaped sclerite ( Tong et al. 2019: fig. 24F)........ T. fugong Tong, Zhang & Li, 2019

- Endogyne without horseshoe-shaped sclerite............................................................. 22

22 (21) Endogyne with only a transverse bar ( Fig. 5D ; Tong et al. 2019: fig. 25D)...................................... 23

- Endogyne with two transverse sclerites, i.e., an anterior transverse sclerite and a posterior transverse bar.............. 24

23 (22) Transverse bar of endogyne nearly straight ( Fig. 5D ).......................................... T. wenfeng sp. nov.

- Transverse bar of endogyne strongly curved ( Tong et al. 2019: fig. 25D)............. T. xinping Tong, Zhang & Li, 2019

24 (22) Recurved arches of epigastric region weakly sclerotized ( Tong et al. 2019: fig. 24G, H).................................................................................................. T. gongshan Tong, Zhang & Li, 2019

- Recurved arches of epigastric region strongly sclerotized ( Tong et al. 2019: fig. 24A)............................. 25

25 (24) Transverse bar of endogyne straight; ALE separated by about 1.0 times their diameter; clypeus height about 1.1 times ALE diameters ( Tong et al. 2019: fig. 3H).......................................... T. bawan Tong, Zhang & Li, 2019

- Transverse bar of endogyne curved; ALE separated by about 1.3 times their diameter; clypeus height about 2.0 times ALE diameters ( Tong & Li 2007: fig. 5)................................................. T. rastrum Tong & Li, 2007

Figures

FIGURE 2. Trilacuna difeng sp. nov., holotype male (A–D) and Trilacuna wenfeng sp. nov., holotype male (E–H). A–B, E–F. Left male palp (A, E. Prolateral view; B, F. Retrolateral view); C–D, G–H. Distal part of palp (C, G. Prolateral view; D. Retrolateral view; H. Dorsal view). Scale bars: 0.20 (A, B), 0.10 (C, D, E, F, G), 0.05 (H).

FIGURE 3. Trilacuna difeng sp. nov., holotype male, SEM. A–B. Left palp (A. Prolateral view; B. Retrolateral view); C–D, G. Palpal bulb (C. Prolateral view; D. Retrolateral view; G. Dorsal view); E–F, H. Distal part of palpal bulb (E. Prolateral view; F. Retrolateral view; H. Dorsal view). bp = basal projection, lb = lateral branch, mb = median branch, ssb = sickle-shaped branch, spr = small projection, tll = tooth-like lobes.

FIGURE 4. Trilacuna difeng sp. nov., paratype female. A, C, E. Habitus (A. Dorsal view; C. Ventral view; E. Lateral view); B, D, F, H. Prosoma (B. Dorsal view; D. Ventral view; F. Lateral view; H. Anterior view); G. Abdomen, ventral view. ehb = elevated hair base, ldi = labium deep incision. Scale bars: 0.40 (A–H).

FIGURE 5. Trilacuna difeng sp. nov., paratype female (A–B) and Trilacuna wenfeng sp. nov., paratype female (C–D). Copulatory organ (A, C. Ventral view; B, D. Dorsal view). ap = apodeme, as = anterior sclerite, glo = globular structure, psp = posterior spiracle, sar = sclerotized, recurved arches, tba = transverse bar, tsc = transverse sclerite. Scale bars: 0.20 (A, B), 0.10 (C, D).

FIGURE 6. Trilacuna wenfeng sp. nov., holotype male. A, C, E. Habitus (A. Dorsal view; C. Ventral view; E. Lateral view); B, D, F, I. Prosoma (B. Dorsal view; D. Ventral view; F. Lateral view; I. Anterior view); G, H. Abdomen (G. Ventral view, arrow shows the cluster of short setae; H. Lateral view). ehb = elevated hair base, ldi = labium deep incision. Scale bars: 0.40 (A–I).