Chinja Polotow & Griswold 2018, new genus
Creators: name: Polotow, Daniele
name: Griswold, Charles
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Zoropsidae
Chinja

description: Chinja Polotow & Griswold, new genus
Etymology. Name is an arbitrary combination of letters and is to be considered feminine in gender.
Type species. Chinja chinja sp. nov., here designated.
Diagnosis. Males of Chinja can be distinguished from other Zoropsidae by a straight PER (Fig. 2A), by lacking a tibial crack, by having a male palpal cymbium with a retrobasal process and the male palpal tibial with a RTA and a retromedian cluster of stout setae (Figs 3A–C, 4A–C, 7, 8). Females have a divided cribellum with cribellar spigots evenly arranged (Fig. 5E, F), and the epigynum with the median plate broad and laterally procurved into hooks, and the lateral lobes each with a wide tooth (Figs 3D, 4D, 6A). The following set of characters can be also helpful to identify the genus: presence of a third tarsal claw, absence of claw tufts and presence of a cribellum and calamistrum.
Family placement. Recent phylogenetic treatments of the oval calamistrum clade (OC Clade), which includes Dionycha and Lycosoidea, haven't yet solved the most inclusive relationships and earlier diverging branches of the OC Clade: these remain problematic. Phylogenetic analyses have utilized morphological (Griswold 1993; Silva- Dávila 2003; Raven & Stumkat 2005; Griswold et al. 2005; Polotow & Brescovit 2006; Piacentini et al. 2013; Ramírez 2014), molecular (Wheeler et al. 2017) and total evidence (Polotow et al. 2015) datasets. Polotow et al. (2015: 151) defined the new family Udubidae Griswold & Polotow 2015 for a set of cribellate, canoe-tapetum spiders from Africa and Madagascar. Based upon placement in previous morphological phylogenies (Griswold 1993, Raven & Stumkat 2005), Campostichomma, an ecribellate genus from Sri Lanka (Polotow & Griswold 2017), was also placed in Udubidae. In the same total evidence analysis, Polotow et al. (2015) enlarged and relimited the Zoropsidae, which was considered a senior synonym of Tengellidae and Zorocratidae. Morphological synapomorphies, all of them homoplastic, were proposed for each family. Wheeler et al. (2017) in a moleculesonly phylogeny treating around 1000 terminals, recovered a well-supported OC Clade ([bootstrap] bs 0.75) as sister group (bs 0.96) to Dionycha (bs 0.71). Thus, the OC Clade and sister-group relation thereof may be considered a strongly corroborated hypothesis in spider evolution. However, family classification within the OC Clade, especially regarding branches diverging earlier, remains problematic. Whereas Polotow et al. (2015) clearly distinguished Udubidae from Zoropsidae, in the molecules-only study of Wheeler et al. (2017, fig. 6) Zoropsidae appeared paraphyletic, with Udubidae nesting between Zoropsidae Griswoldiinae and the other zoropsid subfamilies. Support for this arrangement was very poor (bs 0.10) but several subgroups received good support: Udubidae (bs 0.93), Zoropsidae Uliodoninae (bs 0.95), Zoropsidae Tengellinae (bs 0.98) and Zoropsidae Griswoldiinae (bs 0.99). Because we lack any molecular data for our new genus, Chinja placement requires detailed consideration of the synapomorphies for Udubidae and for Zoropsidae and their included subfamilies (Polotow et al. 2015, fig. 6). Based on the synapomorphies and diagnostic characters of members of the OC Clade, we think Chinja is best considered a member of Zoropsidae, although we without a clear subfamily placement due to insufficient data.
The African Udubidae comprise those spiders similar to Chinja, which have in common with this genus an oval calamistrum (Fig. 6B, C), lack of male epiandrous spigots and a straight posterior eye row with canoe-shaped tapetum. Udubidae differ from Chinja in having a male tibial crack, a ventral tibial process and an additional tegular process on the male palp and by having cribellar setae in discrete groups. Chinja lacks the male tibia crack, has only an RTA and median apophysis and conductor on the tegulum (Figs 7A–G, 8A–E) and has cribellar spigots evenly distributed (Fig. 5E, F).
Description. Small spiders, total length 2.40–5.00; sexual dimorphism slight (Figs 1A, B, 2A–C), femur I/ carapace length ratio 0.74–0.92 for males, 0.73–0.89 for females. Carapace pear-shaped in dorsal view; fovea longitudinal, narrow (Fig. 2A). Ocular area 0.3–0.4 of carapace width, ocular quadrangle about 1.5 times wider than long, widest posteriorly; eight eyes in two rows, both rows nearly straight (Fig. 2A). At least ALE and PME have canoe-shaped tapeta. Clypeus very low, height 0.4–0.5 of AME diameter, 0.03–0.05 of cheliceral length (Fig. 2C). Chelicerae stout with small boss, promargin of fang furrow with three small teeth far removed from fang base, and retromargin with four equal-sized teeth. Chilum very faint, divided; supracoxal sclerites faint, free. Sternum shape nearly round, 2.2–2.4 times longer than wide, with blunt point posteriorly; labium with weak basal notch, 0.8–1.2 times longer than wide; palpal coxae rectangular, parallel, 1.2–1.4 times longer than wide (Fig. 2B), serrula in a single row along endites apical margin. Leg formula 4123; autospasy at coxa-trochanter joint; no retrocoxal hymen; integument with fine fingerprint pattern, nearly smooth (Fig. 9A–D), with plumose setae (sensu Lehtinen 1975) (Fig. 6B, C), no feathery scales; all trochanters notched, I and II deep, III and IV moderate. Femora of legs and palpi with dorsal and lateral spines, patellae lacking spines, tibiae I and II with four pairs of ventral spines, tibia II retroventral spines much stouter than proventral, metatarsi I and II with three pairs of ventral spines, males with, females without lateral spines on tibiae and metatarsi I and II; tibiae and metatarsi III and IV with dorsal, lateral, and ventral spines; palpal femora with dorsal and lateral spines, tibiae and tarsi of females with spines, tibiae and cymbium of males without spines, though there may be stout bristles associated with the median process on the male palpal tibia. Males without a tibial crack on walking legs (Fig. 2A). Calamistrum of female comprising just a few irregularly placed setae (Fig. 6B, C), absent in male. Preening combs and scopulae absent. Superior tarsal claws each with a single row of about 10 teeth, with inferior tarsal claws present on all legs, smooth, claw tufts and tenant setae absent (Fig. 9B–C). Trichobothria absent from leg femora and patellae, tibiae with a basal dorsolateral group and pro and retrolateral rows, the retrolateral row extending to apex; metatarsi with a dorsal, irregular row or dorsal row plus dorsobasal group (Fig. 6B); tarsi with 1–2 irregular, dorsal rows apically (Fig. 9B), trichobothria long, not forming graded series, trichobothrial base with proximal hood with 2–3 transverse ridges (Fig. 9D); palpal tibiae with pro- and retrolateral rows, apparently absent from tarsi; trichobothrial base with proximal hood with 2–3 transverse ridges (Figs 7H, 8E–I). Tarsal organ subapical, capsulate, orifice nearly round (Figs 7I, 9A). Male palpal tibia with broad, retroapical RTA, with several projections (Figs 7B, 8G, H), with a retromedian group of stout bristles (Figs 7H, 8I). Cymbium lacking dorsal scopula, with retrobasal projection, best visible in dorsal and retrolateral views (Figs 3A, C, 4A, C, 7C, 8C, F). Palpal tarsus with large, strap like, sclerotized petiole attached to alveolus; subtegulum cup-shaped, with 4–5 anelli, tegulum U shaped, simple; with sharp prolateral projection cradled by cup-shaped projection of subtegulum (Figs 3B, 4B, 7G, 8E); embolus firmly attached to tegulum, arising on prolateral side of tegulum, flattened and broad to apex; median apophysis convex and weakly hooked apically, flexibly attached to proximo-median part of tegulum (Figs 3A, 4A, 7D, E, 8D); conductor hyaline, originating retroapically on tegulum (Figs 3A, 4A, 7D–F, 8B, D), cradling the apex of embolus (Figs 7F, 8D); fundus in subtegulum, reservoir and ejaculatory duct simple, spiraling around outer margin of tegulum. Pedicel divided into anterior lorum I and posterior lorum II, both rectangular, junction about straight, with slit sensilla along edges of lorum II. Abdomen oval, without scuta (Figs 1A–B, 2A–C). Respiratory system comprising anterior pair of book lungs and four simple posterior tracheae. Epigynum divided into median plate and lateral lobes, median plate broadest posteriorly, lateral lobes with teeth (Figs 2B, 3D, 4D, 6A). Vulva with anterior copulatory duct, spermathecae simple, with fertilization ducts posterolateral (Figs 3E, 4E). Cribellum broad and short, divided, cribellar spigots strobilate (Fig. 5A, E, F). Six spinnerets, ALS and PLS two-segmented, PMS one-segmented (Fig. 5A). The ALS has a pair of large MAP and a tartipore and six PI spigots (Fig. 5B). The PMS (Fig. 5C) lacks a paracribellum, has two CY spigots (one posterior and one median), one anterior AC spigot; there two large apical spigots, with a tartipore in between: these are probably mAP (Fig. 5C). The PLS has three anterior AC spigots, a large anteromedian CY spigot, and an apical tartipore with a large spigot next to it: this spigot with a cylindrical base and long, narrow shaft is probably an MS spigot (Fig. 5D).
Composition. Two species: Chinja chinja sp. nov. and C. scharffi sp. nov.
Natural history. All species have been collected in the leaf litter and on the soil surface of closed-canopy, moist forest. Although the cribellum and calamistrum appear functional, we have no data on the web, if any.
Distribution. Endemic to the Eastern Arc Mountains of Tanzania (Fig.10).
description: Published as part of Polotow, Daniele & Griswold, Charles, 2018, Chinja, a new genus of spider from the Eastern Arc Mountains of Tanzania (Araneae, Zoropsidae), pp. 545-562 in Zootaxa 4472 (3) on pages 547-548, DOI: 10.11646/zootaxa.4472.3.7, http://zenodo.org/record/1440327