Stigmatomma sakalava Esteves & Fisher

Esteves, Flavia A. & Fisher, Brian L., 2016, Taxonomic revision of Stigmatomma Roger (Hymenoptera: Formicidae) in the Malagasy region, Biodiversity Data Journal 4, pp. 8032-8032 : 8032

Stigmatomma sakalava Esteves & Fisher sp. n.

Materials

Type status: Holotype. Occurrence: catalogNumber: casent0366766 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0366766; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomatavy 275; country: Madagascar; stateProvince: Antsiranana; locality: Ampasindava, Andranomatavy Forest ; verbatimElevation: 275; decimalLatitude: -13.6648; decimalLongitude: 47.98702; georeferenceRemarks: ± 500m; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: 3 MaxiWinks, mixed samples; eventDate: 10/06/2013; habitat: disturbed dry forest; fieldNumber: BLF31671; eventRemarks: sifted litter; Record Level: institutionCode: CASC Type status: Paratype. Occurrence: catalogNumber: casent0366765 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0366765; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomatavy 275; country: Madagascar; stateProvince: Antsiranana; locality: Ampasindava, Andranomatavy Forest ; verbatimElevation: 275; decimalLatitude: -13.6648; decimalLongitude: 47.98702; georeferenceRemarks: ± 500m; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: 3 MaxiWinks, mixed samples; eventDate: 10/06/2013; habitat: disturbed dry forest; fieldNumber: BLF31671; eventRemarks: sifted litter; Record Level: institutionCode: CASC Type status: Paratype. Occurrence: catalogNumber: casent0318443 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0318443; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomatavy 275; country: Madagascar; stateProvince: Antsiranana; locality: Ampasindava, Andranomatavy Forest ; verbatimElevation: 275; decimalLatitude: -13.6648; decimalLongitude: 47.98702; georeferenceRemarks: ± 500m; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: 3 MaxiWinks, mixed samples; eventDate: 10/06/2013; habitat: disturbed dry forest; fieldNumber: BLF31671; eventRemarks: sifted litter; Record Level: institutionCode: CASC Type status: Paratype. Occurrence: catalogNumber: casent0366764 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0366764; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomatavy 275; country: Madagascar; stateProvince: Antsiranana; locality: Ampasindava, Andranomatavy Forest ; verbatimElevation: 275; decimalLatitude: -13.6648; decimalLongitude: 47.98702; georeferenceRemarks: ± 500m; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: 3 MaxiWinks, mixed samples; eventDate: 10/06/2013; habitat: disturbed dry forest; fieldNumber: BLF31671; eventRemarks: sifted litter; Record Level: institutionCode: NHMB Type status: Paratype. Occurrence: catalogNumber: casent0318442 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0318442; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomatavy 275; country: Madagascar; stateProvince: Antsiranana; locality: Ampasindava, Andranomatavy Forest ; verbatimElevation: 275; decimalLatitude: -13.6648; decimalLongitude: 47.98702; georeferenceRemarks: ± 500m; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: 3 MaxiWinks, mixed samples; eventDate: 10/06/2013; habitat: disturbed dry forest; fieldNumber: BLF31671; eventRemarks: sifted litter; Record Level: institutionCode: BMNH Type status: Paratype. Occurrence: catalogNumber: casent0318441 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0318441; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomatavy 275; country: Madagascar; stateProvince: Antsiranana; locality: Ampasindava, Andranomatavy Forest ; verbatimElevation: 275; decimalLatitude: -13.6648; decimalLongitude: 47.98702; georeferenceRemarks: ± 500m; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: 3 MaxiWinks, mixed samples; eventDate: 10/06/2013; habitat: disturbed dry forest; fieldNumber: BLF31671; eventRemarks: sifted litter; Record Level: institutionCode: MHNG Type status: Other material. Occurrence: catalogNumber: casent0068192 ; recordedBy: B.L.Fisher et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0068192; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Kirindy 100, 15.5 km; country: Madagascar; stateProvince: Toliara; locality: Foret de Kirindy, 15.5 km 64° ENE Marofandilia ; verbatimElevation: 100; decimalLatitude: -20.045; decimalLongitude: 44.66222; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 11/08/2005; habitat: tropical dry forest; fieldNumber: BLF12455; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0022237 ; recordedBy: Fisher, Griswold et al.; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0022237; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Androngonibe 30; country: Madagascar; stateProvince: Mahajanga; locality: Reserve Speciale de Bemarivo, 23.8 km 223° SW Besalampy ; verbatimElevation: 30; decimalLatitude: -16.925; decimalLongitude: 44.36833; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 11/19/2002; habitat: tropical dry forest; fieldNumber: BLF06692; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0017557 ; recordedBy: Fisher-Griswold Arthropod Team; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0017557; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomite 75; country: Madagascar; stateProvince: Toliara; locality: Foret de Mite, 20.7 km 29° WNW Tongobory ; verbatimElevation: 75; decimalLatitude: -23.52417; decimalLongitude: 44.12133; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 02/27/2002; habitat: gallery forest; fieldNumber: BLF05850; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0015918 ; recordedBy: Fisher-Griswold Arthropod Team; sex: 1w; preparations: pin; associatedMedia: http://www.antweb.org/specimen/casent0015918; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Malaza 40; country: Madagascar; stateProvince: Toliara; locality: Reserve Prive Berenty, Foret de Malaza, Mandrare River, 8.6 km 314° NW Amboasary ; verbatimElevation: 40; decimalLatitude: -25.00778; decimalLongitude: 46.306; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 02/06/2002; habitat: gallery forest; fieldNumber: BLF05426; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0438262 ; recordedBy: Fisher, Griswold et al.; sex: 1w; preparations: SEM mount; associatedMedia: http://www.antweb.org/specimen/casent0438262; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Ankarana 80; country: Madagascar; stateProvince: Antsiranana; locality: Reserve Speciale de l'Ankarana, 22.9 km 224° SW Anivorano Nord ; verbatimElevation: 80; decimalLatitude: -12.90889; decimalLongitude: 49.10983; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 02/10/2001; habitat: tropical dry forest; fieldNumber: BLF02858; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0022146 ; recordedBy: Fisher, Griswold et al.; sex: 1w; preparations: SEM mount; associatedMedia: http://www.antweb.org/specimen/casent0022146; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Mangotoky 100; country: Madagascar; stateProvince: Mahajanga; locality: Parc National de Namoroka, 17.8 km 329° WNW Vilanandro ; verbatimElevation: 100; decimalLatitude: -16.37667; decimalLongitude: 45.32667; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 11/08/2002; habitat: tropical dry forest; fieldNumber: BLF06506; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0017556 ; recordedBy: Fisher-Griswold Arthropod Team; sex: 1w; preparations: SEM mount; associatedMedia: http://www.antweb.org/specimen/casent0017556; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Andranomite 75; country: Madagascar; stateProvince: Toliara; locality: Foret de Mite, 20.7 km 29° WNW Tongobory ; verbatimElevation: 75; decimalLatitude: -23.52417; decimalLongitude: 44.12133; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 02/27/2002; habitat: gallery forest; fieldNumber: BLF05850; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC Type status: Other material. Occurrence: catalogNumber: casent0015917 ; recordedBy: Fisher-Griswold Arthropod Team; sex: 1w; preparations: SEM mount; associatedMedia: http://www.antweb.org/specimen/casent0015917; Taxon: scientificName: Stigmatommasakalava; genus: Stigmatomma; Location: locationID: Malaza 40; country: Madagascar; stateProvince: Toliara; locality: Reserve Prive Berenty, Foret de Malaza, Mandrare River, 8.6 km 314° NW Amboasary ; verbatimElevation: 40; decimalLatitude: -25.00778; decimalLongitude: 46.306; georeferenceRemarks: coordinates obtained from GPS; Identification: identifiedBy: F. Esteves; dateIdentified: 2014; Event: samplingProtocol: MW 50 sample transect, 5m; eventDate: 02/06/2002; habitat: gallery forest; fieldNumber: BLF05426; eventRemarks: sifted litter (leaf mold, rotten wood); Record Level: institutionCode: CASC

Description

Worker (Fig. 88; holotype values within parentheses): HL: 0.74-0.76 (0.76); HW: 0.58-0.61 (0.61); HW2: 0.51-0.57 (0.55); SL: 0.42-0.47 (0.45); ML: 0.44-0.52 (0.46); WL: 0.89-0.94 (0.94); PPW: 0.32-0.36 (0.35); PtL: 0.31-0.36 (0.35); PtW: 0.38-0.44 (0.44); CI: 77-83 (80); SI: 57-62 (60); MI: 58-68 (61); PtI: 80-84 (81).

Head:

Mandibular baso-masticatory margin skirted dorsally by row of filiform setae; ventrally, by row of acuminate flattened-apex setae followed by parallel row of longer filiform setae (Fig. 89a). Mandibular dentition arrangement, from base to apex: single larger tooth; smaller single tooth; four pairs of teeth (dorsal tooth row with teeth increasing in length towards mandibular apex; tooth pairs fused basally); single preapical tooth; apical tooth (Fig. 89a, b). Anterior clypeal margin with eight to ten tubercle-like cuticular processes arranged in a single row (Fig. 89a, c). All clypeal cuticular processes save the most lateral ones armed anteriorly with asymmetrical mucronate dentiform seta; most lateral processes unarmed (Fig. 89a, c). Central-most clypeal cuticular processes around 3x the length of associated dentiform setae. Long, filiform pair of setae on median clypeal area, posterior to the cuticular processes present on anterior margin (Fig. 89a). Pair of shorter, filiform setae on median clypeal area posterior to longer pair of setae (Fig. 89a, c). Clypeal median area extending between antennal sockets posteriorly as a narrow (or not so narrow) longitudinal strip; frontoclypeal sulcus acute or narrowly rounded (Fig. 89a, c). Supraclypeal area a round concavity (Fig. 89a, c). Twelve antennomeres. Genal teeth absent (Fig. 89c). Absence of compound eyes. Palpal formula: 4:2 (four maxillary, two labial; Fig. 89d).

Mesosoma:

In dorsal view, mesonotum narrower than posterior remainder of mesosoma (Fig. 90a). Metanotal suture absent (Fig. 90a). Sulcus dividing mesepisternum into anepisternum and katepisternum; katepisternum somewhat rectangular, with dorsoposterior margin angled (Fig. 90b). Metathoracic spiracle slit like, with swollen margin, reduced in size, located in a shallow concavity (Fig. 90b). Propodeal spiracle round, surrounded by swollen cuticle (Fig. 90b). Face of propodeal declivity not concave (Fig. 90a).

Legs:

Basoventral half of calcar of strigil lamellar (Fig. 91b). Anterior face of calcar of strigil with tubiform microtrichia (Fig. 91a); posterior face with lanceolate microtrichia (Fig. 91b). Multiple paddle-like setae on anteroventral face of protibial apex, next to calcar of strigil (Fig. 91a). Multiple paddle-like setae on anterior face of probasitarsus (Fig. 91a); row of stout setae on posterior face present or absent (Fig. 91b). Single mesotibial spur with lanceolate microtrichia (Fig. 91c). Slit-like longitudinal sulcus on anterodorsal face of mesobasitarsus (Fig. 91d). Some stout setae on inner face of mesobasitarsus. Two metatibial spurs: simple anterior spur, with lanceolate microtrichia; posterior spur pectinate (Fig. 92a). Anterior face of posterior metatibial spur glabrous (Fig. 92a); posterior face with antler-like microtrichia (Fig. 92b). Brush of long, truncated, filiform setae on posterior face of metatibial apex, next to posterior metatibial spur (Fig. 92b). Absence of a longitudinal sulcus on the metabasitarsus (Fig. 92a). Brush of setae present on the baso-inner face of the metabasitarsus, formed anteriorly by acuminate, flattened-apex setae, and posteriorly by truncated, filiform setae (Fig. 92). Some stout setae on remainder of inner face of metabasitarsus. Arolium on pro-, meso-, and metapretarsus.

Metasoma:

Petiole sessile (Fig. 93a). Ventroanterior margin of petiolar tergite anterior dorso-latero-ventral carina (Ward 1990) much shorter than anterior margin of subpetiolar process, in lateral view (Fig. 93a). Ventral margin of subpetiolar process with obtuse angle at midpoint (fin-like projection; Fig. 93a). Absence of fenestra on lateral face of subpetiolar process (Fig. 93a). Petiolar proprioceptor zone a large, round concavity with few sensilla (Fig. 93b). Scrobiculate sulcus between pretergite and postergite of abdominal segment III and presclerites and postsclerites of abdominal segment IV (Fig. 93c). Presence of eight to ten stout, spiniform setae on the apex of hypopygium (Fig. 93d).

Sculpture:

Dorsal face of mandible mostly costate-foveolate, except for smooth apical portion (Fig. 89a, b, c). Median clypeal area costate-scarcely foveate (Fig. 89a, c). Supraclypeal area smooth (Fig. 89a, c). Head, in dorsal view, foveate; area posterior to tentorial pit plicate (Fig. 89c). Labrum confused alveolate to imbricate apically (Fig. 94). Pronotum foveolate dorsally; remainder of mesosoma foveate dorsally (Fig. 90a). Pronotum mostly dispersed foveolate-weakly alveolate laterally (Fig. 90b). Anepisternum dispersed costulate-weakly alveolate; katepisternum alveolate (Fig. 90b). Metapleuron alveolate-slightly costate (Fig. 90b). Lateral face of propodeum slightly costulate-weakly alveolate or mostly alveolate (Fig. 90b); declivitous face smooth, or weakly alveolate (Fig. 90a). Petiolar tergite alveolate anteroventrally and ventrolaterally, grading into foveolate/foveate dorsally (Fig. 93a); laterotergite confused imbricate/alveolate posteriorly (Fig. 93b); poststernite alveolate (Fig. 93b). Abdominal segments III, IV, V, and VI punctate/foveolate (Fig. 93c); abdominal segment VII mostly smooth (Fig. 93d).

Pilosity and color:

Suberect pilosity on head, dorsal face of mesosoma, lateral face of propodeum, petiolar tergite, and abdominal segments III, IV, V, and VI. Petiolar poststernite mostly glabrous. Longer pilosity on abdominal segment VII. Body color orange-brown; appendages yellow to light orange.

Comments on character variation

One specimen was very similar to Stigmatomma sakalava (CASENT0438262; Fig. 95; colleted at Ankarana Special Reserve, at the north limit of S. sakalava range). However, that specimen (herein nicknamed morph B) differs from all other S. sakalava specimens in the following characters:

1. Head: median area of clypeus with longer tubercle-like cuticular processes (approximately 4x the size of the dentiform setae they bear; Figs 95a, 96a). Supraclypeal area is larger (Fig. 96b). Compound eyes are reduced, but present, and possess two ommatidia at their widest diameter (Fig. 96c). The head is round while in S. sakalava it is rectangular (Fig. 95a). Dorsal face of the head is foveolate.

2. Mesosoma: The mesonotum is longer in dorsal view, and the metanotal suture is present (Fig. 97a). Anepisternum and dorsal portion of katepisternum are visibly wider (Fig. 97b, c). Metathoracic spiracle is oblong, larger, and pinched anteriorly (Fig. 97b, c). Metapleural carina is well developed and separates the propodeum from the metapleuron (Fig. 97b, c). The metapleuron is costate, and the lateral face of the propodeum is costate-rugulose-foveolate (Fig. 97b, c).

3. Legs: The simple mesotibial spur bears lanceolate cuticular projections on its ventral margin (Fig. 98a). Brush of setae on the baso-inner face of metabasitarsus is formed by truncated, filiform setae only (Fig. 98b, c).

4. Petiole and gaster: Petiole roughly longer than high, in lateral view (Fig. 95b).The tergite of abdominal segment III is divided into pretergite and postergite by a smooth sulcus; in the tergite of the abdominal segment IV, the sulcus is mostly smooth, and in the sternite of the same abdominal segment, the sulcus is scrobiculate, but shallower than the one found in all other specimens of S. sakalava (Fig. 99a). The apex of the hypopygium is armed with seven stout spiniform setae (Fig. 99b).

5. Body length is much smaller (WL=; Fig. 95b).

6. Body color is yellow (Fig. 95).

Given the morphological variation we found within other Stigmatomma species evaluated in this study, it is expected that some of the character variations mentioned above may naturally occur in S. sakalava . Examples of taxonomically non-informative characters are: presence/absence and size of compound eyes, sculpture impression on head, length of mesonotum, presence/absence and development of metanotal suture, presence/absence and amount of cuticular projections on the ventral margin of the mesotibial spur, number of spiniform setae on the apex of the hypopygium, and body length.

On the other hand, specimen morph B presents character variations that were not found within other species: head shape, shape and width of anepisternum and katepisternum, metathoracic spiracle shape, development of the metapleural carina, type of constituent setae on the brush present at the baso-inner portion of the metabasitarsus, ratio of petiolar height/length, absence of scrobiculation on the sulci dividing the tergites on abdominal segments III and IV, and development of the sulcus dividing the sternite on abdominal segment IV. Also, personal observations indicate that while recently emerged adults are slightly lighter than others in the same colony, the color difference between morph B and other specimens of S. sakalava is striking.

In spite of the differences highlighted above, none of the other characters of the specimen in question differed from those presented in the description of Stigmatomma sakalava . Thus, with just one specimen on hand, we decided to delay its description as a new species until more specimens are available for examination. In addition, specimen morph B and the other specimens of S. sakalava are allopatric to one another, leaving open the possibility of intraspecific isolation-by-distance and a consequential morphologic variation.

Finally, excluding the specimen morph B, there is no geographic pattern in the variation exhibited by the Stigmatomma sakalava specimens we examined regarding body size, the number of dentiform setae on the clypeal anterior margin, amount of clypeus between frontal lobes, number of spiniform setae on the apex of the hypopygium, and scupture.

Other castes

Gynes and males unknown.

Specimens used in prior studies

This taxon was referenced as Stigmatomma MG06 in two previous studies. Yoshimura and Fisher (2012b) used specimen CASENT0022237, and Ward and Fisher (2016) used specimen CASENT0068192-D02.

Diagnosis

Worker

With characters of the tsyhady species-group and the sakalava species-complex as described above, and the following characters (asterisks flag unique characters within the genus in the Malagasy bioregion):

Integument orange-brown (Fig. 88); medium-sized ant (HL: 0.74-0.76, WL: 0.89-0.94).

Dorsal row of teeth of mandible tooth pairs increasing in size towards apex of mandible (Fig. 89a, b).

Flexuous filiform setae ventrally skirting baso-masticatory margin of mandible.

Dorsal face of the head foveate (Fig. 89c).

Genal teeth absent (Fig. 89c).

Palpal formula 4:2 (Fig. 89d).

Dorsal face of pronotum foveolate; dorsal face of remainder mesosoma foveate; declivitous face of propodeum smooth, or weakly alveolate (Fig. 90a).

*Katepisternum and metapleuron mostly alveolate; lateral face of propodeum slightly costulate-weakly alveolate, or mostly alveolate (Fig. 90b).

Mesepisterum divided into anepisternum and katepisterunm; Katepisternum rectangular, with dorsoposterior margin angled (Fig. 90b).

Basoventral half of calcar of strigil lamellar (Fig. 91b).

Anterior face of calcar of strigil with tubiform microtrichia (Fig. 91a).

Single mesotibial spur covered with lanceolate microtrichia (Fig. 91c).

Slit-like longitudinal sulcus present on the anterodorsal face of mesobasitarsus (Fig. 91d).

Anterior face of posterior metatibial spur glabrous (Fig. 92a).

Brush of long, truncated filiform setae present on the posterior face of metatibial apex (Fig. 92b).

Brush of acuminate, flattened-apex setae and truncated, filiform setae present on the baso-inner face of metabasitarsus (Fig. 92).

Absence of a longitudinal sulcus on metabasitarsus (Fig. 92a).

Subpetiolar process fin-like: ventral margin midpoint obtusely angled (Fig. 93a).

Presence of eight to ten stout, spiniform setae on the apex of hypopygium (Fig. 93d).

Stigmatomma sakalava and S. bolabola share the following characters: absence of genal teeth, palpal formula, single mesotibial spur, head sculpture, shape of the subpetiolar process, and presence of stout, spiniform setae on the apex of hypopygium. However, S. sakalava may be distinguished by the smooth or slightly alveolate face of its propodeal declivity, mesosoma lateral face sculpture, katepisternum shape, proportion of lamella on the basoventral margin of calcar of strigil, and distribution (it is not sympatric to any of its congeners).

Etymology

The Sakalava people are an ethnic group of Madagascar. They occupy the area along the western coast of the island, from Onilahy River in the south to the island of Nosy Be in the north ( Feeley-Harnik 1978), overlapping a large part of the range of Stigmatomma sakalava .

Distribution

Stigmatomma sakalava was collected in gallery forests and in dry deciduous forests. All records fall within the limits of the western and southern biomes of Madagascar (sensu Burgess et al. 2004; Fig. 100). Specimens were distributed at elevations ranging from 30 to 300 m. All specimens were recorded from sifted leaf mold and rotten wood (seven collection records).