Cardiocondyla strigifrons

Seifert (2003) - In two sites in Indonesia, nests were found in shallow soil in open, disturbed areas with bare or weakly vegetated ground (Yamauchi, pers.comm. 2001).

Identification
Seifert et al. (2017) - The basic morphology is similar to the condition described for Cardiocondyla itsukii. There are no subjectively perceivable characters known allowing a reliable separation of this species from the next related species Cardiocondyla kagutsuchi. The reduction of dorsal mesosomal sculpture proposed by Seifert (2003) as a character on the basis of a much smaller sample size is also found in other species and is only a statistical difference. Therefore, we omit a lengthy verbal description and refer to combinations of NUMOBAT characters.

There is no doubt that species separation in the C. nuda group is difficult. It requires careful consideration of character definitions and the use high-resolution optical and measurement systems. The diagnose presented here uses numerous morphological characters to achieve an acceptable identification error rate.

Meeting the following definition:


 * Discriminant 176.328×PPH - 49.049×CW + 51.521×SP - 59.844×PPW + 6.61 < 0
 * Discriminant 214.193×PLG - 88.759×SP + 57.676×SL - 106.17×PEH - 10.465 > 0
 * Discriminant 319.279×PLG - 49.672×PPW + 133.938×FRS - 177.726×EYE + 91.370×CW - 63.848×SL - 12.955 < 0
 * Discriminant 75.783×PPH - 157.227×SP + 62.967×PPW - 117.467×SPBA + 101.708×EYE - 17.387 > 0

where:


 * CW: Maximum cephalic width; the maximum is found usually across and including the eyes, exceptionally posterior of the eyes.


 * EYE: Eye-size - the arithmetic mean of the large (EL) and small diameter (EW).


 * FRS: Distance of the frontal carinae immediately caudal of the posterior intersection points between frontal carinae and the lamellae dorsal of the torulus. If these dorsal lamellae do not laterally surpass the frontal carinae, the deepest point of scape corner pits may be taken as reference line. These pits take up the inner corner of scape base when the scape is fully switched caudad and produce a dark triangular shadow in the lateral frontal lobes immediately posterior of the dorsal lamellae of scape joint capsule (Fig. 1).


 * PEH: Maximum petiole height. The straight section of ventral petiolar profile at node level is the reference line perpendicular to which the maximum height of petiole node is measured at node level.


 * PLG: Mean length of pubescence hairs on dorsum of first gaster tergite as arithmetic mean of at least 7 measurements measured at magnifications of 320x.


 * PPH: Maximum postpetiole height; the lateral suture of dorsal and ventral sclerites is the reference line perpendicular to which the maximum height of postpetiole is measured.


 * PPW: Maximum width of postpetiole.


 * SL: Maximum straight line length of scape excluding the articular condyle given as the arithmetic mean of both scapes.


 * SP: Maximum length of propodeal spines; measured in dorsofrontal view along the long axis of the spine, from spine tip to a line that orthogonal to the long axis and touches the bottom of the interspinal meniscus (Fig. 3). Left and right SP are averaged. This mode of measuring is less ambiguous than other methods but yields higher spine length values in species with reduced spines. This is the case in the dentiform spines found in the C. nuda group where it is difficult to correctly define the long axis. In such cases, the deviation of the assumed spine axes from longitudinal mesosomal axis should not exceed 30°.


 * SPBA: Smallest distance of the lateral margins of the spines at their base. This should be measured in dorsofrontal view, since the wider parts of the ventral propodeum do not disturb the measurement in this position. If the lateral margins of spines diverge continuously from the tip to the base, a smallest distance at base is not defined. In this case SPBA is measured at the level of the bottom of the interspinal meniscus.

Distribution
Seifert et al. (2017) - The known range of C. strigifrons extends over 6100 km and goes from Thailand over the Indomalayan Archipelago to Papua New Guinea and north to the south Japanese islands. The absence of very isolated populations suggests that it has a lower tramp species potential.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, Malaysia, New Guinea, Philippines, Singapore. Palaearctic Region: Japan.

Biology
Seifert et al. (2017) - The only known social type is a combination of several ergatoid males, intranidal mating and polygyny (observations in the laboratory of J. Heinze).

Nomenclature

 *  strigifrons. Cardiocondyla nuda subp. strigifrons Viehmeyer, 1922: 211 (w.) INDONESIA (Java). Seifert, 2003a: 256 (q.). Raised to species: Seifert, 2003a: 255.

Worker
Seifert (2003) - type: CS 555, CL/CW 1.230, SL/CS 0.822, PoOc/CL 0.449, EYE 0.220, dFOV 18, FRS/CS 0.262, SP/CS 0.062, SPBA/CS 0.254, PEW/CS 0.292, PPW/CS 0.480, PEH/CS 0.324, PPH/CS 0.292, PEW/PPW 0.609, sqrtPDG 4.03, PLG/CS 6.39 %, MGr/CS 1.53 %.

Head longer than in Cardiocondyla kagutsuchi. CL/CW 1.222; postocular head sides in type specimen notably converging and more linear, in other specimens less converging and more rounded. Median third of anterior clypeal and of occipital margin frequently slightly concave. Postocular index large, PoOc/CL 0.449. Eyes small, EYE 0.220. Frontal carinae immediately caudal of FRS level slightly converging, FL/FR in the type 1.087. Paramedian and lateral areas of vertex with deeply impressed foveolae of 16 - 19 mm diameter, usually with inner corona or flat tubercle of 7 - 9 mm diameter, interspaces much smaller than foveolar diameter, foveolar margins in close contact with longitudinal rugae and their anastomosae. Frontal laminae, clypeus and median area of vertex longitudinally carinulate-rugulose. Median area of vertex between sagittal levels of frontal carinae with few carinulae, scattered and small foveolae imbedded in interspaces. Anterolateral area of vertex and antennal fossae weakly longitudinally rugose. Sculpture of dorsal promesonotum very different from C. kagutsuchi: with foveolae of 16 - 18 mm diameter; foveolar interspaces in type and other specimens as wide as foveolae and shining, only with fragments of very delicate microreticulum; in other specimens foveolae more densely packed and imbedded in irregular rugulose-reticulate structures. Dorsal area of propodeum clearly microreticulate. Lateral area of mesosoma on whole surface regularly and strongly microreticulate; longitudinal sculpture except for 5 - 6 weak and short carinulae on ventrolateral area of metapleuron entirely absent. Whole surface of petiole and postpetiole shining but finely microreticulate. Cuticular surface of first gaster tergite shining, without microsculpture or with very fine microreticulum. Propodeal spines reduced to blunt dents. Dorsal profile of mesosoma in type and few other specimens curved: promesonotum and propodeum convex, metanotal groove shallow, tips of spines significantly lower than top level of mesosoma. Dorsal profile of mesosoma in most other specimens from mesonotum caudad to spine tip more or less straight, interrupted only by shallow metanotal groove, tips of spines almost as high as top level of mesosoma. Petiole profile similar to that of Cardiocondyla mauritanica. Petiole node in dorsal aspect slightly longer than wide. Postpetiole in dorsal view with clearly angulate sides and slightly concave anterior margin that is a little shorter than posterior margin; wider than in C. kagutsuchi, PPW/PPL 1 .333 ± 0.035 [1.293 - 1.383] (n = 7). Postpetiolar sternite in type specimen with flat anteromedian bulb, in other specimens with a small rectangular anteromedian corner and 2 curved paramedian carinae or bulbs (i.e. there are 3 weakly prominent structures). Whole body dark brown or blackish, appendages and mandibles lighter.

Queen
Seifert (2003) - Head elongated, CL/CW 1.215. Occipital margin more or less straight. Scape moderately long, SL/CS 0.799. Median portion of anterior clypeal margin straight. Frontal carinae in posterior half rather straight and parallel. Vertex with densely packed and deep foveolae of 16 - 18 mm diameter, demarcated by (or arranged between) longitudinal rugulae. Clypeus and frontal laminae longitudinally carinulate-rugulose; rugae on lateral area of clypeus incurving frontad, with two rugae fusing to a single semicircular ruga on anteriormost area of clypeus. Whole dorsal area of pronotum, mesonotum, praescutellum, scutellum, and anterodorsal area of propodeum with densely-arranged and deep foveolae. Lateral area of pronotum, mesopleuron, and lateral area of propodeum strongly microreticulate. Lateral lobes of praescutellum widely separated. Propodeal spines reduced to acutely-angled dents. Petiole node smooth, but finely microreticulate and with few, fine microrugae; in dorsal aspect circular or slightly longer than wide; lateral aspect of petiole as in C. mauritanica. Postpetiole less shining and with few shallow foveolae and microreticulum; in dorsal view with straight or slightly concave anterior margin and markedly angulate sides forming an angle of 115 - 1300; PPW/PPL 1.375 ± 0.042 [1.298 - 1.416] (n = 6). Postpetiolar sternite with 2 curved paramedian carinae or bulbs, a blunt anteromedian corner is occasionally present. Concolorous dark or blackish brown, appendages lighter.

Type Material
Java [type investigated].

1 worker type labelled “Java” and “Cardiocondyla nuda Mayr strigifrons Viehm.”,.

References based on Global Ant Biodiversity Informatics

 * Okita I., K. Murase, T. Sato, K. Kato, A. Hosoda, M. Terayama, and K. Masuko. 2013. The spatial distribution of mtDNA and phylogeographic analysis of the ant Cardiocondyla kagutsuchi (Hymenoptera: Formicidae) in Japan. Sociobiology 60(2): 129-134.
 * Seifert B. 2003. The ant genus Cardiocondyla (Insecta: Hymenoptera: Formicidae) - a taxonomic revision of the C. elegans, C. bulgarica, C. batesii, C. nuda, C. shuckardi, C. stambuloffii, C. wroughtonii, C. emeryi, and C. minutior species groups. Annalen des Naturhistorischen Museums in Wien. B, Botanik, Zoologie 104: 203-338.
 * Seifert B., I. Okita,and J. Heinze. 2017. A taxonomic revision of the Cardiocondyla nuda group (Hymenoptera: Formicidae). Zootaxa 4290: 324-356.
 * Viehmeyer H. 1922. Neue Ameisen. Archiv für Naturgeschichte (A)88(7): 203-220.