Tetramorium alternans Santschi, 1929

Csösz S., Radchenko, A. & Schulz, A., 2007, Taxonomic revision of the Palaearctic Tetramorium chefketi species complex (Hymenoptera: Formicidae)., Zootaxa 1405, pp. 1-38 : 1

1. Tetramorium alternans Santschi, 1929 (figs 11-17)

Tetramorium caespitum var alternans Santschi, 1929: 150 ([[worker]]); TYPE MATERIAL: LECTOTYPE [[worker]] and PARALECTOTYPE [[workers]] designated below (3[[workers]] / NHMB); for the locality details see lectotype designation; raised to species rank: Güsten et al. 2006: 27;

Tetramorium biskrensis var. kahenae Menozzi, 1934: 162 ; first available use of Tetramorium caespitum st. biskrensis var. kahenae Santschi, 1918: 155 ([[worker]]); TYPE MATERIAL: LECTOTYPE [[worker]] designated below, for locality details see lectotype designation (1[[worker]] / MCSN); Tetramorium biskrense kahenae : Mei 1995: 764; New synonymy

Redescription of worker (figs 14-17). Small to medium size, CS 733 [652, 820]. Whole body and appendages greyish black to black.Head nearly square CL/CW 1.01 [0.97, 1.05], with very feebly convex sides, straight, or slightly concave occipital margin and narrowly rounded occipital corners. Eyes small, EYE 0.168 [0.155, 0.176]. Frons moderately wide, FR/CS 0.39 [0.37, 0.41], frontal lobes as wide as frons, FL/FR 1.0 [1.0, 1.0]. Scape very short, SL/CS 0.71 [0.69, 0.74], without dorsal carina basally, surface feebly costulate. Promesonotal dorsum slightly convex, metanotal groove shallow, but distinct. Propodeal teeth moderately long, slightly curving upwards. Dorsal surface of petiole steeply rounded backward, NOH/NOL 1.03 [0.94, 1.13], petiole relatively high, PEH/NOL 1.84 [1.68, 2.04]. Whole body and appendages greyish black to black. General appearance coarsely rugose, ground surface microreticulate. Head dorsum longitudinally rugose and microreticulate, occiput and sides rugoso-reticulate and microreticulate. Alitrunk dorsum rugose or rugoso-reticulate and microreticulate. Mesopleuron usually coarsely microreticulate. Dorsum of petiolar node ruguloso-reticulate and microreticulate, medially microreticulate. Dorsum of postpetiole microreticulate. Polygonal striation continuous on 1st gastral tergite (see fig. 8.). Ventral surface of head with several short and few moderately long setae arising posteriorly to buccal cavity (see fig. 5.).

Description of Gyne (figs 11-13). Small size, CS 999 [948, 1025]. Whole body and appendages greyish black. Head wider than long, CL/CW 0.92 [0.90, 0.95], with straight subparallel sides, straight occipital margin and narrowly rounded occipital corners. Frons moderately wide, FR/CS 0.41 [0.40, 0.42], frontal lobes as wide as frons, FL/FR 1.0 [1.0, 1.0]. Scape very short, SL/CS 0.69 [0.65, 0.71], without dorsal carina basally, moderately smooth and shiny. Head wider than scutum, MW/CS 0.94 [0.92, 0.97]. Propodeal teeth very short. Dorsal crest of petiolar node in frontal view straight. Petiolar node dorsum steeply rounded backward. Petiole and postpetiole relatively narrow, WAIST 0.93 [0.83, 1.0]. General appearance rugulose, ground surface smooth, more or less shiny. Head dorsum, occiput and sides ruguloso-reticulate, ground surface feebly microreticulate. Frons longitudinally rugulose and feebly microreticulate. Scutum and scutellum longitudinally rugulose, scutellum more or less smooth medially. Sides of alitrunk ruguloso-reticulate and feebly microreticulate, ventral part of katepisternum always smooth. Dorsum of petiolar node feebly reticulate and smooth, dorsum of postpetiole usually smooth. Polygonal striation disrupted on 1st gastral tergite, occasionally superficially striate basally. Ventral surface of head with several short and few longer setae, arising posteriorly to buccal cavity.

Description of Male. Whole body and appendages black. Head with feebly convex sides, slightly rounded occipital margin and widely rounded occipital corners. Scutum wider than head. Propodeal teeth very short, propodeum angulate in profile. Dorsal crest of petiolar node with sharp transversal edge, slightly emarginated in frontal view. Head, alitrunk and waist finely sculptured, ground surface microreticulate. Head feebly reticulate ground surface microreticulate, dull. Scutum feebly rugulose, laterally and anteriorly smooth and shiny. Scutellum longitudinally rugulose, usually shiny medially. Sides of alitrunk, smooth and shiny. Dorsum of petiolar node finely reticulate and microreticulate, postpetiole smooth and shiny. Polygonal striation disrupted on 1st gastral tergite.

Material examined (8 nest series including 34 workers, 6 gynes and 3 males). ALGERIA - Takersan 04.1893 leg. Anonymous (4[[workers]] / MNHN) ; MOROCCO - Moyen Atlas, Rd 3211 14 Rkm N. Rd 3485, 40 km S. Ain Leuh, 1100 masl , leg. Aßmuth, Güsten, Sanetra, Schulz, Schumann (6[[workers]] / PCAS) ; TUNISIA - Hammamet , 26.04.1982. nr. 8. leg. H. Sheratin (2[[workers]], 1[[queen]], 1[[male]] / HNHM) , nr. 9, 27.04.1982. leg. H. Sheratin (7[[workers]], 3[[queens]] / MSNM) , nr. 23, 30.04.1982. leg. H. Sheratin (2[[workers]], 1[[queen]], 2[[males]] / MSNM) ; Hammamet, Sousse , 03.1974. nr. 804 . leg. Novellini (4[[workers]] / MSNM) ; Kabylie , 31.05.65. leg. Cagniant (4[[workers]] / MSNM) ; Sfax , 1904. leg. Bíró (5[[workers]]; 1[[queen]] / HNHM) .

Morphometrics (34 workers and 5 gynes measured).

Diagnosis. Workers of T. alternans can be separated from related species by the lack of psammophore, relatively small eyes, (EYE, Table 1.), very short scape (SL/CS, Table 1.) without dorsal carina basally, less coarse body sculpture (i.e. dorsum of petiolar node is feebly ruguloso-reticulate and microreticulate), rounded petiolar node (NOH/NOL and PEH/NOL, Table 1.). Workers of T. alternans mostly resemble those of T. sanetrai n. sp., but petiole and firons characters (NOH/NOL, PEH/NOL,FR/CS, Table 1.) give appropriate separation between them. To separate these species see Discriminant D(2b) function given under T. sanetrai n. sp.

Gynes of T. alternans can be recognised by the lack of psammophore, very short and smooth scape (SL/ CS, Table 2.), wide scutum (MW/CS, Table 2.), relatively narrow petiole and postpetiole (WAIST, Table 2.), and feebly reticulate petiole and postpetiole.

For further combination of morphometric characters see Table 1-2.

Lectotype designation of Tetramorium alternans Santschi, 1929 . In order to avoid further nomenclatural problems it is necessary to designate a lectotype.We investigated three syntype workers mounted on one pin, labeled as: “Type” [red label] [-] “ Rabat ” [ Morocco] “ Otin ” [-] 1.quinz. Aout 28 [in original description: 04.1928] [-] “ T. caespitum alternans Sant. ” SANTSCHI det. 19“29” [last two numbers are hardly readable] [-] Sammlung Dr. F. Santschi Kairouan ;

These data correspond to the original description ( Santschi, 1929: 150.). The lectotype is positioned on the distal end of the upper card (this is mentioned on the reverse side of lectotype label). The lectotype specimen is in very good condition.

Morphometric data of alternans lectotype worker: CL: 700; CW: 685; FR: 275; FL: 275; SL: 485; ML: 770; MW: 440; PEW: 230; PEH: 255; NOH: 145; NOL: 140; PEL: 150; PPW: 265; PPL: 165; PPH: 210; SPL: 90; SPSP: 140; EL: 135; EH: 100; ED: 180.

Lectotype designation of Tetramorium biskrense kahenae Menozzi, 1934 . Santschi described this taxon based on several workers and gynes from different localities (Kairouan, Hammalif, Monastir, Pichon, Mines de Garn el Fyriat), and in order to prevent further nomenclatural problems it is necessary to designate a lectotype. Only one syntype worker specimen was investigated, labeled as: “ T. caespitum ” [/] “st. Biskrense For ” [/] ìv. Kahenae Santì [/] “ Garn el Fayah” [now Garn Alfaya mines] [/] “ Tunisien ” [/] “(Santschi)” [this label written with red ink] .

These data correspond to the original description ( Santschi, 1918: 155.). In the present designation we fix this specimen as the lectotype. The lectotype specimen is in good condition, partly covered by glue.

Morphometric data of kahenae lectotype worker:

CL: 790; CW: 790; FR: 305; FL: 305; SL: 555; ML: 880; MW: 485; PEW: 240; PEH: 285; NOH: 170; NOL: 165; PEL: 175; PPW: 305; PPL: 185; PPH: 265; SPL: 110; SPSP: 135; EL: 165; EH: 115; ED: 200.

Distribution. This species seems to be endemic to the Mediterranean coast of NW Africa. It is reported from Morocco, Algeria, Tunisia and a dubious record from Lampedusa (Aria Rossa) ( Mei 1995).