Mallinus Simon, 1893

Haddad, Charles R., Henrard, Arnaud & Jocque, Rudy, 2019, Revision of the ant-eating spider genus Mallinus Simon, 1893 (Araneae, Zodariidae), ZooKeys 822, pp. 141-158 : 143-147

Genus Mallinus Simon, 1893

Mallinus Simon, 1893: 436; Jocqué 1991: 136.

Type species.

Mallinus nitidiventris Simon, 1893, by monotypy.

Diagnosis.

Mallinus can be distinguished from other zodariine spiders by the relatively smaller size of the anterior median eyes, which are only slightly larger than the lateral and posterior eyes, while generally much larger than the other eyes in other zodariines. Mallinus shares with Palfuria Simon, 1910 the scale-like extensions on the endites and the considerably raised cephalic region, but lacks the carapace modifications at the posterior end of the cephalic region typical for most Palfuria ( Szüts and Jocqué 2001); rather, the carapace slopes steeply at the posterior end of the cephalic region, with only a shallow transverse depression. Mallinus also have a very globose abdomen, which is usually higher than long in both sexes, a rare condition amongst other zodariines.

Description.

Small spiders, 2.13-2.72 mm in length. Carapace longer than wide, with cephalic region similar in length to thoracic region; cephalic region rounded anteriorly, parallel-sided laterally, thoracic region almost circular, broadest at middle of coxa II (Figs 1, 2, 5); cephalic width about 0.77 times thoracic width in males and 0.88 times maximum width in females (cephalic width measured on posterior tangent of PME); carapace in lateral view with strongly convex clypeus, raised behind PER, highest at coxa I, with steep slope in posterior half (Figs 3, 4); surface deeply granulate, sparsely covered in short straight setae with swollen bases, with scattered small pores (Figs 6-10); fovea slit-like, on posterior slope, at two-thirds carapace length (Figs 2, 5, 9). Eye region reasonably broad, AER procurved, PER strongly procurved (Figs 5, 10), with anterior margin of PME behind posterior margin of PLE; all eyes surrounded by black rings; MOQ width equal anteriorly and posteriorly, slightly longer than wide (Fig. 10). Chilum absent. Chelicerae small, narrowed distally, directed posteroventrally; fangs very short and thick (Fig. 11), with posterior groove that anterior margin of endites fits into (Fig. 12); cheliceral promargin with anteromesal cusp provided with one small tooth; setae scarce, each plastron with two long setae; endites almost parallel-sided, rounded distally, converging at midline in front of labium, apically with scale-like extension (Fig. 13), prolateral edge with field of flattened denticles (Fig. 14); labium subtriangular, broader than long (Fig. 11); sternum shield-shaped, as long as broad (Figs 55, 57), surface deeply granulate, covered in scattered erect setae; pleural bars isolated; precoxal triangles small, distinct; intercoxal sclerites absent between coxae I & II, present between coxae II & III and III & IV. Leg formula 4321 (contra 4123 in Jocqué 1991), leg IV clearly longer than others; legs covered in mix of short straight, finely barbed setae and incised setae (Fig. 15); femoral organ present on all legs, with single brush-like, densely barbed seta, lying in faint groove riddled with small pits, similar in structure on all four femora (Figs 16-19); patellae without distinct indentation, with lyriform organ retrolaterally at half their length (Figs 20, 21); metatarsi with dense field of short chemosensory setae dorsally (Figs 22, 23), single distal trichobothrium (Figs 24, 25), scattered longer chemosensory setae and barbed setae; metatarsus stopper present, weakly elevated dorsally (Fig. 25); metatarsi without distinct preening comb, metatarsi II–IV with four longer thicker incised setae distally (Figs 26, 27); tarsi ventrally with paired rows of short needle-like setae; tarsal claws paired, with large teeth on margin facing opposing claw (Figs 28, 29), several trichobothria (Fig. 30), chemosensory setae (Fig. 31), subdistal suture (Fig. 29) and weakly elevated oval tarsal organ (Fig. 32); female palpal tarsus conical, with single large claw with three large teeth, turned inward more than 45° (Fig. 33), palpal patella with lyriform organ retrolaterally (Fig. 34). Abdomen globose, higher than long in females, similar in males, with circumferential folds laterally (Fig. 35) and shiny scutum covering dorsum in both sexes (Figs 1-4); petiole short (Fig. 36); abdominal dorsum with sparse covering of short straight setae with fine brachiae, denser ventrally (Fig. 37); epigastric region weakly sclerotised; venter only with inframamillary sclerite present, transversely broad, with row of flattened setae (Figs 38, 39). Spinnerets: ALS of females (Figs 38, 40) and males (Figs 41, 42) long, conical, with central major ampullate gland spigot surrounded by several piriform gland spigots; PMS and PLS of females not studied by SEM, absent in males. Epigyne simple, with median lobe and two adjacent lateral lobes posteriorly incorporating copulatory openings (Figs 43, 47, 50); entrance ducts short, directed slightly laterally, entering lateral spermathecae with three spirals (Fig. 51). Male palp with unmodified femur and patella; tibia with single sharp triangular RTA, curved distally, extending approximately one-quarter the cymbium length (Figs 44, 48, 49, 52, 53); tarsus with triangular cymbium (Fig. 44), with baso-retrolateral process, with broad distal claw and single modified toothed seta prolaterally (Figs 45, 46); embolus long, whip-like, originating retrolaterally, curving around proximal and prolateral margins of tegulum, fine at distal end, tip associated with narrow membranous conductor; MA originating medially on tegulum, C-shaped, with swollen base but sharp end (Figs 48, 52).

Relationships.

In a morphological phylogeny of Zodariidae , Jocqué (1991) placed Mallinus in the Zodariinae, as sister group to Ranops Jocqué, 1991 + Zodarion . However, its position would have been clearer had adult specimens been available for study. This lack resulted in a considerable number of missing entries in the character matrix relating to genitalic morphology. Henrard and Jocqué (unpubl.) include a single male M. nitidiventris (from Tswalu Kalahari Reserve, MRAC 216253) in their molecular phylogeny of Zodariidae . Their results suggest that Mallinus is most closely related to Palfuria .

This sister group relationship is also well supported by morphological characters. Mallinus shares with Palfuria the deeply granulate tegument of the carapace, the strongly raised cephalic region with a steep slope in the posterior half, the scale-like extensions on the endites, the circumferential folds of the abdomen (this character is conspicuous in males and females when the abdomen is not distended), and the subdistal suture on the tarsi. The subdistal suture was also observed in Akyttara Jocqué, 1987 and Heradida Simon, 1893, to which they are also closely related. In the phylogeny of Henrard and Jocqué (unpubl.), Ranops appears to be placed as the sister group of a clade containing Akyttara , Heradida , Mallinus and Palfuria , forming a strongly supported monophyletic group. Those zodariines belong to a monophyletic clade characterized by the presence of a unique femoral organ on the legs ( Henrard and Jocqué 2017).