Palindroma, Rudy Jocqué & Arnaud Henrard, 2015

Rudy Jocqué & Arnaud Henrard, 2015, The new spider genus Palindroma, featuring a novel synapomorphy for the Zodariidae (Araneae), European Journal of Taxonomy 152, pp. 1-33 : 3-5

Palindroma gen. nov.

urn:lsid:zoobank.org:act:2FF14DA8-1CEB-4F1A-941F-1DE1B368257D

Type species

Palindroma morogorom sp. nov.

Diagnosis

Representatives of Palindroma gen. nov. are typical sturdy Cryptothelinae with ALE in front of AME and slightly recurved to straight posterior eye row; sternum shield shaped with straight anterior margin and without precoxal sclerites; posterior legs with numerous short spines in combination with longer ventral spines; teguments of carapace, legs and abdomen often provided with patches of white or silvery setae. Male palp with large patella, large subtegulum and tegulum provided with retrolateral knob; median apophysis absent.

Palindroma gen. nov. is easily separated from Capheris Simon, 1893 and Systenoplacis Simon, 1907 by the absence of anterior concavities of the sternum.It deviates from Caesetius Simon, 1893 , Psammorygma and Rotundrela Jocqué, 1999 by the absence of precoxal sclerites, from Aschema Jocqué, 1991 by the unmodified posterior legs and from Psammoduon Jocqué, 1991 by the absence of fans of supple spines on the legs; in Cydrela the sternum is slightly indented in front, the cephalic area in the carapace profile much higher and the posterior eye row more strongly recurved.

Etymology

The genus name is derived from the English term ‘palindrome’ originating from the Greek ‘παλινδρομος’, that refers to words or sentences that are identical whether they are read from front to back or the other way round. All species names of the new species described here are palindromes. The gender of the species name is feminine.

Description

Medium size spiders (7.5–10 mm) with reticulated to roughly granulate teguments. Carapace longer than wide (L/W <1.43–1.71), slightly protruding anteriorly, with silvery hairs in male, almost hairless in females apart from a few longer hairs on clypeus; widest at level of coxae II–III, narrowed to about 0.48–0.62 times maximum width in males and 0.62–0.71 times maximum width in females (cephalic width measured on posterior tangent of PME). Cervical grooves poorly indicated. Profile flat or domed, highest at level of first coxae and with slight dip at level of fovea.

Colour: carapace medium to dark brown; chelicerae, legs, mouthparts and sternum medium to orange brown; abdomen dorsum grey with one to seven pale spots and four reddish apodemes, sides and venter white to pale grey; in males sclerotized in front of epigastric fold.

Eyes in three rows: ALE in front of AME and further apart, posterior row straight or slightly recurved and eyes far apart. All eyes subequal, AME dark, other eyes pale. Clypeus straight, slightly slanting back, height 2.5 to 4 times diameter of ALE, sometimes with some long dispersed setae.

Chilum double, about or slightly more than twice as wide as high, lateral margin poorly defined; without setae. Chelicerae slightly conical, inner margin almost straight, with many evenly dispersed setae; with distomesal membranous lamina ( Fig. 1 A–B); fangs shorter than wide at base. Labium inverted Ushaped, with slightly narrowed base. Endites roughly triangular, converging, with basolateral extension accommodating palpal coxae. Sternum shield-shaped, as wide as long, without triangular extensions or precoxal sclerites; anterior margin straight, lateral margins slightly sinuous.

Legs: robust. Formula 4123 or 4132. Spination reduced on legs I and II, well developed on III and IV. Most spines short and thick except dorsal ones on F and ventral ones on T and Mt. Patella III and IV with retrolateral boss at base of short spine. Anterior tarsi fusiform in male, usually longer than metatarsi, unmodified in female. One dorsal hinged hair on tibiae and metatarsi I and II ( Fig. 1 D). Trochanters with anterior concavity. Prolateral tibial process strongly developed on all legs in both sexes (see Fig. 17 A–E). Three tarsal caws, paired ones with numerous teeth ( Fig. 1 C).

Female palp with numerous prolateral spines and some retrolateral ones ( Fig. 1 E); palpal claw with some small teeth at base ( Fig. 1 F); turned inward over less than 45°; without distal patch of chemosensitive setae.

Abdomen oval, with ventral row of small sclerotized apodemes; tracheal spiracle fairly small, somewhat advanced and provided with small rectangular scutellum. Both exes with six spinnerets. ALS large, conical, biarticulate. PLS and PMS provided with 1 and 3 cylindrical gland spigots, respectively. Colulus represented by haired field.

Male palp: complexity of palps very variable; patella larger than tibia ( Fig. 2A ), sometimes modified; RTA sometimes very small, in other species well developed. Cymbium with prolateral spines; without distal claw; sometimes with basal swelling(s); subtegulum strongly developed, sclerotized and visible in unexpanded palp; tegulum with retrolateral boss ( Fig. 2B ), variable in shape; embolus short, flat, distal part with flange.

Epigyne with central longitudinal depression. Spermathecae large, far apart; copulatory ducts with thick walls ( Fig. 2C –F).

Note

The species Palindroma obmoimiombo gen. et sp. nov. is only tentatively and probably temporarily incorporated in the genus. It lacks several of the specific generic characters: the indented profile of the carapace, the membranous lamina of the chelicerae, the enlarged male palpal patella. On the other hand, it has a field with spinules on the flat mesal surface of the chelicerae. The latter character approaches conditions in Caesetius but that genus has a high domed carapace, precoxal sclerites and a much more strongly recurved posterior eye row. The species apparently belongs to an as yet undescribed genus but with only one species and in the absence of females we have refrained from creating a new genus for it.

Distribution

Palindroma is found in forest and miombo regions of central and eastern Africa in the Democratic Republic of the Congo, Malawi and Tanzania.

Key to males

1. Chelicerae almost rectangular as viewed in front, with distomesal extension well developed, without mesal field of spinules; carapace domed, with slight dip at level of fovea; palp with swollen patella, tibia with one RTA or RTA poorly developed …………………………………………2 – Chelicerae conical, with distomesal extension, inconspicuous, with mesal field of spinules; carapace profile flat, without dip; palp with unmodified patella, with two RTA …… P. obmoimiombo sp. nov.

2. Carapace profile with slight dip at level of fovea; anterior tarsi with same length as metatarsi or longer; palp with conspicuous RTA …………………………………………………………………3

– Carapace profile with marked dip at level of fovea; anterior tarsi shorter than metatarsi; palp with inconspicuous RTA ………………………………………………………………… P. sinis sp. nov.

3. Anterior tarsi clearly longer than metatarsi; tegulum with well-developed basal or retrolateral extension ……………………………………………………………………………………………4

- Anterior tarsi only slightly longer than metatarsi; tegulum with longitudinal ventral ridge ending medially in poorly developed knob ……………………………………………… P. avonova sp. nov.

4. RTA thin, long and strongly tapered apically; tegulum sub-apically with retrolateral knob ………… ………………………………………………………………………………… P. morogorom sp. nov.

- RTA broad, short, with strongly sclerotized rounded extremity; tegulum basally with welldeveloped conical extension …………………………………………………… P. aleykyela sp. nov.

Figures

Fig. 1. Palindroma morogorom gen. et sp. nov. Scanning electron miocrographs. A – D. ♂ from Kigogo Reserve. E – F. Paratype ♀. A. Right chelicera, ventral view, arrow shows membranous lamina. B. As previous, detail. C. Leg I, tarsal claws, lateral view. D. Tibia I, hinged hair (black arrow), trichobothrium (white arrow). E. ♀ right palp, lateral view. F. Detail of previous. Scale bars: A, E – F = 100 mm, B – D = 50 mm.

Fig. 17. Palindroma morogorom gen. et sp. nov. A. Left legs I and II, frontal view; arrows indicate tibial process. B. Left leg III, tibia and metatarsus, dorsal view. C. Detail of previous. D. Left leg II, tibia and metatarsus, dorsal view. E. Detail of previous. Scale bars: A – B = 0.5 mm, C – D = 100 mm, E = 50 mm.

Fig. 2. — A – D. Palindroma morogorom gen. et s p. nov. Scanning electron miocrographs. A – B. ♂ from Kigogo Reserve. C-D. ♀ from Uzungwa Scarp Forest Reserve, paratype. A. ♂ palp, expanded, retrolateral view. B. Idem, anterolateral view. Arrow shows tegular retrolateral boss. C. Epigyne, digested, dorsal view. D. Idem, detail. — E – F. Palindroma avonova gen. et sp. nov., paratype, ♀. E. Epigyne, digested, dorsal view F. Idem, detail. Scale bars: A – C, E = 200 mm, D, F = 100 mm.