Taxonomic studies on seven species of the genus Opopaea (Araneae, Oonopidae) from Kenya

Seven species of the genus Opopaea Simon, 1892 from Kenya are recognized, including five new species: O. berlandi (Simon & Fage, 1922), O. kulczynskii (Berland, 1914), O. makadara Tong & Li, sp. nov. (♀♂), O. ngangao Tong & Li, sp. nov. (♀♂), O. ngulia Tong & Li, sp. nov. (♂), O. sheldrick Tong & Li, sp. nov. (♀♂), and O. wundanyi Tong & Li, sp. nov. (♀♂). Morphological descriptions and illustrations of all the species are given. All types are preserved in the National Museums of Kenya in Nairobi, Kenya (NMK).


Introduction
Opopaea Simon, 1892 is one of the most species rich genera of the spider family Oonopidae Simon, 1890, distributed in tropical and subtropical regions. A total of 182 valid extant species are currently known (WSC 2019).
Although Opopaea is one of the most diverse and widely distributed oonopid genera, we know surprisingly little about the overall diversity of this group in Africa. Saaristo and Marusik (2008) recognized 20 species of Opopaea from Africa and adjacent islands, five of which were new to science. Andriamalala and Hormiga (2013) recorded 27 species from Madagascar, 26 species of which were newly described. Only five species are known for Kenya, namely, O. berlandi (Simon & Fage, 1922), O. foulpointe Andriamalala & Hormiga, 2013, O. hoplites (Berland, 1914), O. kulczynskii (Berland, 1914) and O. simoni (Berland, 1914). Here we recognize seven species of the genus Opopaea from Kenya, five of which are new to science. All species which are reported in this paper are described and figured.

Materials and methods
The specimens were examined using a Leica M205C stereomicroscope. Details were studied under an Olympus BX53 compound microscope. Photos were taken with a Canon EOS 750D zoom digital camera (18 megapixels) mounted on an Olympus BX53 compound microscope. Scanning electron microscope images (SEM) were taken under high vacuum with a Hitachi TM3030 after critical point drying and goldpalladium coating. All measurements were taken using an Olympus BX53 compound microscope and are in millimeters.
The materials are preserved in the National Museums of Kenya in Nairobi, Kenya (NMK).
Abbreviations used in the text: posterior lateral eyes; PME posterior median eyes; PME-PME distance between PME and PME; PLE-PME distance between PLE and PME; PTL patella length; TL total length. Diagnosis. Males can be recognized by the tubercle-shaped ridges on posterior part of sternum (arrow in Fig. 1F), the very small booklung covers (Fig. 1H), and the truncate tip of cymbiobulbus (Fig. 2E); females are recognized by the dark, linguiform projection on the epigastric scutal ridge (lpr in Fig. 23A).
Description. Male. Yellow. Habitus as in Fig. 1A, C, E. Body length 1.20. Carapace ( Fig. 1B): wide oval in dorsal view; sides with longitudinal streaks; dorsal area finely reticulate, with some setae at lateral edges, several setae on the posterior margin of dorsal surface with very large hair base. Eyes: ALE largest, PLE smallest; posterior eye row recurved viewed from above, procurved from front; ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME separated by less than PME radius. Clypeus height about 0.9 times ALE diameter (Fig. 1G). Sternum as long as wide, fused to carapace; surface finely reticulate, with medium sized pits, with a pair of tubercle-shaped ridges on posterior part (arrows in Fig. 1F); radial furrows present only between coxae I-II,   II-III. Anterior end of endites with a small, sharply pointed projection. Legs light yellow. Abdomen: booklung covers very small, ovoid, without setae. Pedicel tube short, ribbed, with small, dorsolateral, triangular extensions, scuto-pedicel region as high as diameter of pedicel, with arched scutal ridges and curved anterior scutal ridge (Fig. 1I). Palp (Figs 2, 21A-C): reddish brown; femur slightly shorter than half the length of patella and inserted at the patella submedially; patella very large; cymbiobulbus shorter than the patella, tip of the cymbiobulbus broad.
Female. As in male except as noted. Habitus as in Fig 8E) and the dark, small, linguiform projection in the middle of the female epigastric scutal ridge (Fig. 24A). Opopaea manongarivo has acute tip of male palpal bulb and smooth epigastric scutal ridge of female (Andriamalala and Hormiga 2013: figs 635, 643, 645).
Description. Male (holotype). Yellow. Habitus as in Fig. 7A, C, E. Body length 1.32. Carapace (Fig. 7B): wide oval in dorsal view; sides with longitudinal streaks; dorsal area finely reticulate with some setae at lateral edges. Eyes: ALE largest, PLE smallest; posterior eye row straight viewed from above, procurved from front; ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME separated by less than PME radius. Cl-   ypeus height about 1.4 times ALE diameter (Fig. 7G). Sternum (Fig. 7F) as long as wide, fused to carapace; surface finely reticulate, with medium sized pits; radial furrows present. Anterior end of endites with a small, sharply pointed projection. Legs light yellow. Abdomen: booklung covers very small, ovoid, without setae. Pedicel tube short, ribbed, with small, dorsolateral, triangular extensions, scuto-pedicel region as high as diameter of pedicel, with arched scutal ridges, interrupted medially, with curved anterior scutal ridge (Fig. 7H). Palp (Figs 8, 21D-F): reddish brown; palpal femur slightly shorter than half the length of palpal patella and inserted at the patella submedially; patella very large; cymbiobulbus shorter than the patella; palpal fenestra large and located at one third the length of the palp. Tip of the palp with one large, round protuberance.
Female. As in male except as noted. Habitus as in Fig. 9A, C, E. Body length 1.50. Endites without projections. Copulatory organ (Figs 9H, 24A Distribution. Known only from the type locality.  (Berland, 1914), but can be distinguished by the large, curved protuberance on the tip of the male palp (Figs 11E, 22D), and the very narrow postgynal depression of female epigastric region (Fig. 24C). Opopaea hoplites has a small protuberance on the tip of the male palp and a very large postgynal depression of female (Saaristo and Marusik 2008: figs 34, 37B).

Opopaea ngangao
Description. Male (holotype). Reddish brown. Habitus as in Fig. 10A, C, E. Body length 2.08. Carapace (Fig. 10B): wide oval in dorsal view; sides with longitu-   dinal streaks; dorsal area smooth, with some setae at lateral edges. Eyes: ALE largest, PLE smallest; posterior eye row recurved viewed from above, procurved from front; ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME separated by less than PME radius. Clypeus height about 0.9 times ALE diameter (Fig. 10G). Sternum (Fig.  10F) longer than wide, fused to carapace; surface smooth; radial furrows present. Anterior end of endites with a small, sharply pointed projection. Legs light yellow. Abdomen: booklung covers very small, ovoid, without setae. Pedicel tube short, ribbed, with large, dorsolateral, triangular extensions, scuto-pedicel region lower than diameter of pedicel, with arched scutal ridges and straight anterior scutal ridge (Fig. 10H). Palp (Figs 11, 22D-F): reddish brown; palpal femur about two thirds the length of patella and inserted at the patella submedially; patella large; cymbiobulbus as long as the patella; palpal fenestra large and located at nearly the tip of the palp. Tip of the palp with one large, curved protuberance.
Female. As in male except as noted. Habitus as in Fig Distribution. Known only from the type locality.  (Berland, 1914), but can be distinguished by the small body size and the cymbiobulbus which is shorter than the patella (Fig. 21G). Opopaea simoni has large body size and the cymbiobulbus is as long as the patella (Saaristo and Marusik 2008: figs 85, 90).

Opopaea ngulia
Description. Male (holotype). Yellow. Habitus as in Fig. 13A, C, E. Body length 1.51. Carapace (Fig. 13B): oval in dorsal view; sides with longitudinal streaks; dor-  sal area granulate, with some hairs at lateral edges. Eyes: ALE largest, PLE smallest; posterior eye row recurved viewed from above, procurved from front; ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME separated by less than PME radius. Clypeus height about 1.3 times ALE diameter (Fig. 13G). Sternum (Fig. 13F) as long as wide, fused to carapace; surface finely reticulate; radial furrows present, with rows of small pits. Anterior end of endites with a small, sharply pointed projection. Legs light yellow. Abdomen: booklung covers small, ovoid, without setae. Pedicel tube short, ribbed, with large, dorsolateral, triangular extensions, scuto-pedicel region lower than diameter of pedicel, with arched scutal ridges and straight anterior scutal ridge (Fig. 13H). Palp (Figs 14, 21G-I): reddish brown; palpal femur about half the length of patella and inserted at the patella submedially; patella strongly bumped dorsally; cymbiobulbus shorter than the patella; palpal fenestra large and located near the tip of the bulb. Tip of the palp with a small protuberance.
Female. Unknown. Etymology. The specific name is a noun in apposition taken from the type locality. Diagnosis. The new species is similar to O. antsiranana Andriamalala & Hormiga, 2013, but can be distinguished by the hook-like protuberance on the tip of the male palp (Fig. 16E) and the triangular postgynal depression of female (Fig. 23E). Opopaea antsiranana has a slightly curved male palp tip and very short and narrow postgynal depression of female (Andriamalala and Hormiga 2013: figs 318, 323, 326, 328).

Measurements. Male
Description. Male (holotype). yellowish brown. Habitus as in Fig. 15A, C, E. Body length 1.75. Carapace (Fig. 15B): oval in dorsal view; sides with longitudinal streaks; dorsal area granulate, with some hairs at lateral edges. Eyes: ALE largest, PLE smallest; posterior eye row procurved viewed from above, procurved from front; ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME separated by less than PME radius. Clypeus height about 1.2 times ALE diameter (Fig. 15G). Sternum (Fig. 15F)   longer than wide, fused to carapace; surface finely reticulate; radial furrows present, with rows of small pits. Anterior end of endites with a small, sharply pointed projection. Legs light yellow. Abdomen: booklung covers small, ovoid, without setae. Pedicel tube short, ribbed, with small, dorsolateral, triangular extensions, scuto-pedicel region lower than diameter of pedicel, with nearly straight scutal ridges (Fig. 15H). Palp (Figs 16, 21J-L): reddish brown; palpal femur less than half the length of patella and inserted at the patella submedially; patella large; cymbiobulbus shorter than the patella; palpal fenestra small and located at nearly the tip of the palp. Tip of the palp with a hook-like protuberance.
Female. As in male except as noted. Habitus as in Fig. 17A, C, E. Body length 1.85. Endites without projections. Copulatory organ (Figs 17G, 23E, F): postgynal depression small, triangular, about one third the width between the lateral apodemes; with a short, stick-shaped dark mark in the depression; there is a paddle-like sclerite (pls) dorsally, with thin, long, distal curved arms; nail-like process (nlp) well separated.

Opopaea wundanyi
Description. Male (holotype). Blackish brown. Habitus as in Fig. 18A, C, E. Body length 1.90. Carapace (Fig. 18B): wide oval in dorsal view; sides with longi-      tudinal streaks; dorsal area smooth, with some hairs at lateral edges. Eyes: ALE largest, PLE and AME nearly equal sized; posterior eye row recurved viewed from above, procurved from front; ALE separated by their radius, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME separated by less than PME radius. Clypeus height about equal to ALE diameter (Fig. 18G). Sternum (Fig. 18F) longer than wide, fused to carapace; surface smooth; radial furrows present. Anterior end of endites with a small, sharply pointed projection. Legs brown, short, thick and spineless. Abdomen: booklung covers very small, ovoid, without setae. Pedicel tube short, ribbed, with small, dorsolateral, triangular extensions, scuto-pedicel region lower than diameter of pedicel, with arched scutal ridges and curved anterior scutal ridge (Fig. 18H). Palp (Figs 19, 22G-I): reddish brown; palpal femur about half the length of patella and inserted at the patella submedially; patella large; cymbiobulbus shorter than the patella; palpal fenestra large and located at nearly the tip of the palp. Tip of the palp very narrow.