Stigmatomma tsyhady species group

This group is comprised of the following Malagasy species, arranged in two complexes:

sakalava complex
 * Stigmatomma bolabola
 * Stigmatomma janovitsika
 * Stigmatomma sakalava

tsyhady complex
 * Stigmatomma irayhady
 * Stigmatomma liebe
 * Stigmatomma roahady
 * Stigmatomma tsyhady

Diagnosis
Workers with the following combination of characters (asterisks flag unique characters within the genus in the Malagasy bioregion):

1. * Twelve antennomeres;

2. * Four maxillary palpomeres (palpal formula: 4:3 or 4:2);

3. * Calcar of strigil not completely pectinate; baso ventral lamella generally visible (in one species the lamella is reduced to a basal bud); A reduced lamella on the baso ventral margin of the calcar of strigil is often difficult to visualize under a stereomicroscope, and the calcar may appear completely pectinate while in reality it has a basal bud on the base of its ventral margin. Nonetheless, the proportion of lamellar tissue on the ventral margin of the calcar is constant within species, and was helpful to delimit certain species.

4. Anterior face of the calcar of strigil with strap like or tubiform microtrichia basally; Presence and shape of microtrichia on anterior and posterior face of the calcar of strigil are not visible under a stereomicroscope. However, those characters are informative to diagnose groups of species.

5. * Posterior face of the calcar of strigil with lanceolate microtrichia; Presence and shape of microtrichia on anterior and posterior face of the calcar of strigil are not visible under a stereomicroscope. However, those characters are informative to diagnose groups of species.

6. Absence of any longitudinal carina on the dorsal face of metabasitarsus; The longitudinal parallel carinae on the dorsal face of the Stigmatomma besucheti metabasitarsus somewhat converge at their apexes; thus, the region between them appears groove-like in dorsal view. No other species of Stigmatomma in the Malagasy region presents such a character. However, one species, S. roahady, possesses a longitudinal sulcus on the anterior face of its metabasitarsus, and since its shape and location are different from the carinae on S. besucheti, we did not consider them homologous.

7. * Petiolar proprioceptor zone a large, round concavity.

This group can be split into subgroups based on morphological similarities, here called species complexes.

sakalava species-complex
In addition to the characters of the species group (asterisks flag unique characters within the genus in the Malagasy bioregion):

8. Genal teeth present or absent;

9. Two labial palpomeres (palpal formula: 4:2);

10. Antler -like microtrichia present on posterior face of posterior metatibial spur; The presence and shape of microtrichia on the posterior face of the metatibial spur are not visible under a steromicroscope; however, it is informative to diagnose groups of species.

11. Absence of fenestra on the subpetiolar process;

12. Stout spiniform setae present on the apex of hypopygium.

tsyhady species-complex
In addition to the characters of the species group (asterisks flag unique characters within the genus in the Malagasy bioregion):

8. Genal teeth present;

9. * Three labial palpomeres (palpal formula: 4:3);

10. Posterior face of posterior metatibial spur mostly glabrous; The presence and shape of microtrichia on the posterior face of the metatibial spur are not visible under a steromicroscope; however, it is informative to diagnose groups of species.

11. * Fenestra present on the subpetiolar process;

12. * Absence of stout spiniform setae on hypopygium.

Related Pages

 * Key to Malagasy Stigmatomma
 * Stigmatomma besucheti species group
 * Stigmatomma