Vitsika
Creators: name: Bolton, Barry
name: Fisher, Brian
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Vitsika

description: Genus Vitsika
(Figs 81-122, Maps 149-162)
Vitsika Bolton & Fisher gen. n.
Type-species: Vitsika crebra sp. n., by present designation.
Diagnosis of worker
Monomorphic myrmicine ants.
Mandible triangular; masticatory margin with 6-8 teeth and longer than the basal margin.
Palp formula 5,3.
Stipes of maxilla with a strong transverse crest; portion of stipes distal to the crest distinctly depressed and concave.
Clypeus with longitudinal rugulae on median portion, two of which may be enhanced to produce a weakly bicarinate appearance; posteriorly moderately narrowly inserted between the frontal lobes (width of clypeus between the frontal lobes about equal to the width of one lobe).
Clypeus with an unpaired median seta that arises just above a narrow anterior clypeal apron.
Clypeus with lateral portions not raised into a shielding wall or sharp ridge in front of the antennal sockets.
Frontal carinae present, divergent posteriorly, extending back almost to the posterior margin of the head.
Antennal scrobes present, above the eye.
Antenna with 12 segments, with an apical club of 3 segments.
Torulus with upper lobe concealed by the frontal lobe in full-face view, or its extreme outer edge just visible.
Eyes present, in dorsal view located slightly to distinctly in front of the midlength of the side of the head capsule.
Head capsule without a median, longitudinal carina; occipital carina conspicuous.
Pronotal humeri angulate to weakly, obtusely dentate in dorsal view.
Promesonotum more or less evenly shallowly convex in profile, not swollen or domed; propodeal dorsum in profile continues the line of the promesonotum.
Promesonotal suture absent; metanotal groove absent or present.
Propodeum strongly bispinose; propodeal lobes small and rounded.
Propodeal spiracle behind the midlength of the sclerite, in profile well below the dorsal margin, and one spiracle diameter or slightly more in front of the margin of the declivity; one spiracle diameter or less from the apex of the metapleural gland bulla.
Metasternal process absent; a pair of low carina arise anterior to the metasternal pit and diverge posteriorly, one on each side of the pit.
Tibial spurs: mesotibia 0 or 1; metatibia 0 or 1; sometimes the spurs extremely reduced, hardly distinguishable from the setae at the tibial apices.
Abdominal segment 2 (petiole) with a long anterior peduncle, with a dentiform anteroventral process; spiracle situated from slightly behind to distinctly in front of midlength of peduncle.
Abdominal segment 2 node narrow, high-domed to cuneate in profile; ventral surface indented and angled below the node.
Stridulitrum present on pretergite of abdominal segment 4.
Abdominal segment 4 (first gastral) tergite does not broadly overlap the sternite on the ventral gaster; gastral shoulders absent.
Sting simple, strongly developed.
Main pilosity of dorsal head and body consists of simple setae, present and numerous on all dorsal surfaces of head and body. Scapes with elevated pubescence but without standing setae. Dorsal (outer) surfaces of mesotibiae and metatibiae with standing setae present.
Sculpture. Basically similar in all species. Mandibles superficially sculptured to weakly longitudinally costulate; sculpture tends to fade out towards the masticatory margin. Dorsum of head between frontal carinae longitudinally costulate, the costulae divergent posteriorly; spaces between costulae with reticulate-punctulate ground-sculpture that varies from weak to pronounced. Costulae never form a reticulum anywhere on the head, but a few anastomoses may occur near the posterior margin. Area within scrobe predominantly reticulate-punctulate, sometimes also with a few weak rugulae; above the eye usually with 1-3 longitudinal costulae or rugulae. Dorsum of mesosoma reticulate-rugose, most strongly developed on pronotum. Side of pronotum reticulate-rugose towards the dorsum, more longitudinally rugose on lower half of side. Mesopleuron with sparse (ca 5-7) longitudinal rugae, at least the lower ones oblique; these rugae usually extend onto the metapleuron. Gaster unsculptured.
Diagnosis of queen (gyne)
Queens are known for all species except obscura. Characters are as in the worker, except for the usual developments of the mesosoma seen in alates. The queens may be alate or ergatoid, or both forms may occur within a single species (see Table 4). It is possible that all species will be found to produce both ergatoids and alates when the species are better represented in collections. Two species (manifesta, suspicax) exhibit morphological intermediates between alate and ergatoid forms, and two species (acclivitas and crebra) appear to be polygynous. The alate queen has three distinct ommatidia and a characteristically large mesosoma with a full complement of flight sclerites; the pronotum is well represented on the dorsal mesosoma, and the mesopleuron has a strong transverse sulcus. Ergatoids have a mesosoma that is usually larger than in true workers but much smaller than in alates. The mesonotum is frequently hypertrophied in ergatoids with respect to the worker caste, and 1-3 ommatidia are usually present, although only a vestigial median ocellus may be remain; there is no transverse sulcus on the mesopleuron. Intermediates between these two extremes exhibit a mesosoma that is alate-like but much smaller in size, usually with most or all sclerites of the pterothorax represented but in a reduced form, fused together, and with no trace of wing attachments; 3 ocelli are always present in these forms. Venation: see under male.
Diagnosis of male
Worker-associated males are known for crebra, breviscapa and labes. In addition, the males of three other species, collected in isolation (in Malaise traps), are present in CASC. Similar in size to the conspecific worker or slightly smaller. Mandible triangular and distinctly dentate, with 5-7 teeth. Palp formula 5,3 (in situ counts). Stipital crest present on maxilla. SI 30-52. Antenna with 13 segments, conspicuously not filiform, characteristically modified. First funicular segment short but not globular, about 0.40-0.60 x the length of the second funicular segment. Funiculus segment 8 (= antennal segment 9) about equal in length to the scape. Funiculus segment 9 (= antennal segment 10) strikingly elongate, 1.45-1.80 x SL, and the funiculus with a kink or angle between the elongate ninth segment and the tenth. The three apical funicular segments (10-12) are also elongate and form a slender club, of which at least the apical segment is longer than SL (sometimes 2 or all 3 apical segments are> SL). Eyes large, located at or in front of the midlength of the sides. Ocelli conspicuous. Occipital carina sharp but not forming a raised crest. Mesoscutum in profile strongly overhangs the pronotum, the latter not visible in dorsal view. Mesotibia and metatibia each with a single, simple spur. Notauli variably developed, from vestigial to having anterior arms present. Mesopleuron with a transverse sulcus present. Propodeum usually unarmed and rounded, but in some the posterodorsal angle is reinforced by a carina, or the angle projects as a low, obtuse tooth; propodeal lobes rounded. Petiole in profile slightly longer than postpetiole. Petiole with an anterior peduncle, the spiracle at, or slightly in front of, the midlength of the peduncle, well in front of the level of the low, rounded node. Subpetiolar process minute to absent. Parameres large. Cerci present. Pilosity simple everywhere.
Forewing venation (based on males of six species, and alate queens of crebra and miranda). Rsf4-5 does not meet Rf3 on anterior margin of wing (= marginal cell open). 2rs-m absent. 1m-cu present. Fusion of Rs+M extended distally, so that 1m-cu arises from Rs+M, not from M. Rsf3 present (Rs+M divides into Rsf3 and Mf3- 4 proximal of the junction with 2r-rs). Mf3-4 is usually represented only by a short stub (entirely absent in the single alate queen of miranda). First discal cell small, its anterior margin (Rs+M) only about half the length of its posterior margin (Cu-f1-2). A-f2 absent or a mere stub distal to cu-a; the latter is retracted and arises from M+Cu, proximal of the point where it divides into Mf1 and Cuf1-2.
Preliminary key to Vitsika males
1 Propodeal dorsum, or the upper half of the propodeal declivity, or both, with a median, longitudinal carina...............2
- Propodeal dorsum and declivity without trace of a median longitudinal carina......................................5
2 Postpetiole in dorsal view very obviously longer than broad (W/L ca 0.80)..................................... labes
- Postpetiole in dorsal view broader than long (W/L> 1.00).....................................................3
3 Propodeal median longitudinal carina is absent from the declivity; it is confined to the dorsum and terminates in a pair of obliquely laterally directed carinae at the junction of dorsum and declivity. In profile the propodeum armed with a very low, broadly triangular tooth; the apex of this tooth, in posterior view, is seen as the junction of 4-5 short carinae male sp. A
- Propodeal median longitudinal carina is present on the upper half of the declivity, and may be present or absent along the dorsum. Propodeum unarmed, or at most with a low, rounded carina, without a broad triangular tooth and without a confluence of 4-5 carinae in posterior view ............................................................................ 4
4 Median longitudinal carina absent from propodeal dorsum. Colour entirely yellow. Scape relatively long, SL 0.27 (SI ca 50); funiculus segment 9 ca 1.57 x SL..................................................................... crebra
- Median longitudinal carina present on propodeal dorsum. Colour entirely dark brown. Scape relatively short, SL 0.20 (SI ca
32); funiculus segment 9 ca 1.47 x SL.............................................................male sp. B
5 Postpetiole in dorsal view longer than broad. Colour dull yellow with infuscated patches. Upper arc of eye surrounded by a broad, shallow trench.......................................................................... breviscapa
- Postpetiole in dorsal view broader than long. Colour dark brown. Upper arc of eye not surrounded by a broad, shallow trench. ........................................................................................... male sp. C
Diagnoses of the males of breviscapa, crebra and labes are given under species discussions. Critical characterisations of the unassociated males are as follows.
Male sp. A: HL 0.71, HW 0.58, CI 82, SL 0.20, SI 34, mesoscutum maximum width 0.66, WL 1.16, EL 0.34, MfL 0.92. Propodeal dorsum with a broad, open rugoreticulum anteriorly, near the metanotum. Propodeum with a median longitudinal carina that is restricted to the dorsum and does not extend onto the declivity. Propodeum in profile with a low, broad triangular prominence at junction of dorsum and declivity, the apex of which, in dorsal or posterior view, is seen as the confluence of 4-5 short carinae. Postpetiole in dorsal view broader than long. Colour dark brown. [Specimen data: Prov. Fianarantsoa, Foret d’Ambalagoavy Nord, MA-01-12-01, CASENT0995378 (Harin’Hala et al.) (CASC).] Only two worker-based species have been recorded from Fianarantsoa Prov., miranda and obscura; this male may belong to one of them.
Male sp. B: HL 0.71, HW 0.63, CI 89, SL 0.20, SI 32, mesoscutum maximum width 0.63, WL 1.16, EL 0.31, MfL 0.88. Propodeal dorsum reticulate-punctate, with weak longitudinal rugulae laterodorsally, and also with a longitudinal median carina that extends along the dorsum and down the upper half of the declivity. Propodeum on each side with an elevated but rounded, raised crest that separates declivity from sides. Postpetiole in dorsal view broader than long. Colour dark brown. [Specimen data: Prov. Toliara, P.N. Andohahela, ESE Mahamavo, Malaise trap, BLF 5009, CASENT0080565 and 0080566 (Fisher et al.) (CASC).]
Male sp. C: HL 0.58, HW 0.49, CI 84, SL 0.20, SI 41, mesoscutum maximum width 0.50, WL 0.88, EL 0.26, MfL 0.66. Propodeal dorsum almost unsculptured, with only faint traces of weak punctulation. Propodeum without a median longitudinal carina on either the dorsum or the declivity. Declivity separated from sides of propodeum by a very fine carina; in profile the propodeum appears unarmed and the dorsum rounds evenly into the declivity. Postpetiole in dorsal view broader than long. Colour dark brown. [Specimen data: Prov. Toamasina, Ankerana, BLF 27860, CASENT0275575 (B.L. Fisher et al.) (CASC).]
Comments on Vitsika
The 14 species discussed here present a strikingly uniform appearance in terms of sculpture and pilosity, as well as an extremely limited range of standard indices. They obviously represent a very compact single group. Unfortunately, Vitsika workers are currently diagnosed among the myrmicines only by the presence of a unique combination of characters. As with many other myrmicine genera no unique morphological apomorphy can yet be cited. It is defined by its possession of the following characters in combination: mandible with 6 or more teeth; palp formula 5,3; stipital crest strongly present; antenna 12-segmented, with a 3-segmented club; clypeus with an isolated median seta set above a narrow anterior apron; clypeus posteriorly narrowly inserted between the frontal lobes; frontal carinae present and long, extending almost to the posterior margin of the head; antennal scrobes present; mesosomal dorsal outline simple; petiole pedunculate; first gastral tergite does not overlap the sternite on the ventral surface of the gaster; gastral shoulders absent.
Synopsis of Vitsika species
acclivitas Bolton & Fisher sp. n.
astuta Bolton & Fisher sp. n.
breviscapa Bolton & Fisher sp. n.
crebra Bolton & Fisher sp. n.
disjuncta Bolton & Fisher sp. n.
incisura Bolton & Fisher sp. n.
labes Bolton & Fisher sp. n.
manifesta Bolton & Fisher sp. n.
miranda Bolton & Fisher sp. n.
obscura Bolton & Fisher sp. n.
procera Bolton & Fisher sp. n.
suspicax Bolton & Fisher sp. n.
tenuis Bolton & Fisher sp. n.
venustas Bolton & Fisher sp. n.
Key to Vitsika species (workers)
Note. This key excludes ergatoid gynes and alate-ergatoid intermediates (i.e. any worker-like individual which possesses a hypertrophied mesonotum, or has 1-3 ocelli, or has both these features present, is omitted).
1 Full adult colour red-brown, dark brown, or almost black; decidedly not yellow....................................2
- Full adult colour yellow to light brownish yellow............................................................6
2 With petiole node in posterior view the dorsal margin markedly concave across part or most of the width........... incisura
- With petiole node in posterior view the dorsal margin convex, varying from shallowly convex to almost conical..........3
3 In profile the postpetiole almost paniform (Fig. 99), long and low, the node distinctly longer than the postpetiole is high, and with a long, shallowly convex dorsal outline............................................................. labes
- In profile the postpetiole distinctly nodiform (Figs 102, 105, 108), the node at least as high as the postpetiole is long, usually higher, and the node with a strongly convex dorsal outline.....................................................4
4 In posterior view the dorsum of the petiole node is very narrowly rounded, rising medially to a point that is blunt to acute. Petiole node in posterior view tall and slender, higher than wide, its height (from midpoint of the dorsal margin of the foramen to the apex) 1.10-1.23 x its maximum width........................................................... manifesta
- In posterior view the dorsum of the petiole node is broadly and shallowly convex to almost flat medially. Petiole node in posterior view low and broad, wider than high, its height (from midpoint of the dorsal margin of the foramen to the apex) 0.78-0.92 x its maximum width...................................................................................5
5 Smaller species, HL 0.78-0.84, HW 0.62-0.73, SL 0.54-0.63, WL 1.00-1.08. Metafemur shorter, MfL 0.68-0.78 (MfL/HW 1.06-1.09). Antennal scape brown, about the same shade as the head capsule or fractionally lighter (Fig. 106). Full adult colour of head and mesosoma blackish brown to black. Mesopleuron with 7-8 relatively crowded longitudinal costulae, the spaces between them with weak punctulate ground-sculpture................................................... miranda
- Larger species, HL 0.91-0.92, HW 0.75-0.78, SL 0.68-0.69, WL 1.20-1.22. Metafemur longer, MfL 0.86-0.88 (MfL/HW 1.11-1.16). Antennal scape yellow, conspicuously lighter in shade than the head capsule (Fig. 109). Full adult colour of head and mesosoma brown. Mesopleuron with 5-6 relatively widely spaced longitudinal costulae, the spaces between them almost entirely smooth................................................................................. obscura
6 Dorsum of postpetiole entirely covered with dense, conspicuous reticulate-punctate ground sculpture, and also with some weak rugulae. Propodeal spines short and their apices close together in relation to postpetiole width (Figs 90, 92): in dorsal view maximum width of postpetiole 1.95-2.25 x the length of a propodeal spine; maximum width of postpetiole 1.25-1.50 x the distance between the apices of the propodeal spines. In addition, postpetiole in dorsal view 1.35-1.45 x broader than long ............................................................................................... crebra
- Dorsum of postpetiole usually smooth, but sometimes with weak or partial punctulation, or with a few laterodorsal costulae.
Propodeal spines always longer and their apices closer together in relation to postpetiole width: in dorsal view maximum width of postpetiole 0.90-1.60 x the length of a propodeal spine; maximum width of postpetiole 0.82-1.22 x the distance between the apices of the propodeal spines. In addition, postpetiole in dorsal view 1.00-1.38 x broader than long.................7
7 Antennal scape relatively shorter, SI 73-76. Propodeal spines relatively shorter, maximum dorsal width of postpetiole 1.25-1.60 x the length of a spine (only rarely <1.30). Metafemur always slightly shorter than head width (MfL/HW 0.85-0.92). Petiole node in profile low, thick from front to back, and with an oblique to broadly rounded dorsal surface (Fig. 87) breviscapa
- Antennal scape relatively longer, SI 80-91. Propodeal spines relatively longer, maximum dorsal width of postpetiole
0.90-1.36 x the length of a spine (only extremely rarely> 1.25). Metafemur about the same length as, or slightly longer than, head width (MfL/HW 0.98-1.13). Petiole node in profile high, narrow from front to back, and usually narrowly rounded to bluntly cuneate dorsally ................................................................................ 8
8 In profile the postpetiole almost paniform, long and low, the node distinctly longer than the postpetiole is high, and with a shallowly convex dorsal outline. (Fig. 120).............................................................. venustas
- In profile the postpetiole distinctly nodiform, the node at least as high as the postpetiole is long, usually higher, and the node with a strongly convex dorsal outline ...................................................................... 9
9 With petiole in profile the dorsal surface of the peduncle runs into the anterior face of the node through a very obtuse angle, so that the anterior face of the node slopes upwards and posteriorly at only a shallow angle relative to the dorsum of the peduncle (Fig. 81)...................................................................................... acclivitas
- With petiole in profile the dorsal surface of the peduncle runs into the anterior face of the node through slightly more than a right-angle, so that the anterior face of the node slopes upwards and posteriorly at a steep angle relative to the dorsum of the peduncle (Figs 84, 93, 114, 117)......................................................................... 10
10 Average size of worker larger, HW 0.60-0.71, SL 0.54-0.62, MfL 0.66-0.80. Petiole node smooth, without costulae or rugulae on the anterior, lateral or posterior surfaces. Postpetiole in dorsal view smooth, without punctulate sculpture and without longitudinal costulae laterodorsally........................................................................ astuta
- Average size of worker smaller, HW 0.48-0.62, SL 0.38-0.52, MfL 0.48-0.66. If HW 0.60-0.62 and SL 0.50-0.52, then petiole in profile with fine costulae or rugulae that ascend the anterior surface, traverse the upper portion of the lateral surface, and usually overlap onto the posterior surface. Postpetiole in dorsal view with weak but obvious punctulate sculpture, at least on the posterior half, and laterodorsally with longitudinal costulae present..........................................11
11 With mesosoma in profile the dorsal outline of the propodeum rises to a marked peak or angle posterior to the site of the metanotal groove, then descends abruptly and steeply to the dorsal base of the propodeal spine (Fig. 93). Petiole node entirely unsculptured.................................................................................. disjuncta
- With mesosoma in profile the dorsal outline of the propodeum is usually evenly, shallowly curved from the site of the metanotal groove to the dorsal base of the propodeal spine. If a weak angular prominence is present in the outline of the propodeal dorsum, then the petiole node has sculpture on some or all of its surfaces........................................12
12 Eye smaller, with 5-6 longitudinal rows of ommatidia, and with 6-7 ommatidia in the longest row. Smaller species, WL 0.62-0.74, MfL 0.45-0.52, HW 0.46-0.52, SL 0.38-0.45. Postpetiole in dorsal view 1.20-1.38 x broader than long. Propodeal spines usually (but not always) strikingly downcurved along their length (Fig. 117)............................. tenuis
- Eye larger, with 7-8 longitudinal rows of ommatidia, and with 9-10 ommatidia in the longest row. Larger species, WL 0.84-0.96, MfL 0.54-0.66, HW 0.53-0.60, SL 0.46-0.52. Postpetiole in dorsal view 1.08-1.20 x broader than long. Propodeal spines never strikingly downcurved along their length (Figs 111, 115)...........................................13
13 With petiole node in profile its sculpture conspicuous, with distinct costulae or rugulae that ascend the anterolateral surface, traverse the upper side of the node, and usually overlap onto the posterior surface. Dorsum of postpetiole mostly to entirely weakly punctulate, and also with laterodorsal longitudinal costulae present................................... procera
- With petiole node in profile its sculpture weak to vestigial, at most with very feeble, slender costulae that ascend the anterolateral surface, and with traces of punctulate sculpture laterally; posterior surface of node smooth. Dorsum of postpetiole mostly to entirely unsculptured, at most with some weak punctulation posteriorly, and laterodorsal longitudinal costulae or weak punctulation may be present....................................................................... suspicax
description: Published as part of Bolton, Barry & Fisher, Brian, 2014, The Madagascan endemic myrmicine ants related to Eutetramorium (Hymenoptera: Formicidae): taxonomy of the genera Eutetramorium Emery, Malagidris nom. n., Myrmisaraka gen. n., Royidris gen. n., and Vitsika gen. n .., pp. 1-99 in Zootaxa 3791 (1) on pages 68-73, DOI: 10.11646/zootaxa.3791.1.1