Polyrhachis semiinermis

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Polyrhachis semiinermis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Cyrtomyrma
Species: P. semiinermis
Binomial name
Polyrhachis semiinermis
Donisthorpe, 1941

MCZ-ENT001 Polyrhachis-semiinermis hal.jpg

MCZ-ENT001 Polyrhachis-semiinermis had.jpg

Specimen Label

A cryptic label reference stating the types were collected from a tree "Site - empty cell in back of nest found in tree" (Donisthorpe 1941) and a second collection bears included this information label "Narra plantation with abaca understory". These records are all that is known about the biology of Polyrhachis semiinermis.


Characterised by widely rounded pronotal shoulders and a petiole that is virtually parallel-sided with the petiolar teeth reduced to mere denticles or completely lacking. Based on these characters, P. semiinermis is much more closely related to Polyrhachis danum from Borneo and Polyrhachis brevinoda from Australia than to Polyrhachis rastellata. (Kohout 2006)



Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


Known only from a few collections.



Known only from workers.


The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • semiinermis. Polyrhachis (Cyrtomyrma) rastellata var. semiinermis Donisthorpe, 1941j: 209 (w.) PHILIPPINES. Raised to species: Kohout, 2006b: 91.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Black, shining, articulations of scape, palpi, apex of trochanters and base of femur narrowly, extreme tip of antennae, spurs and claws reddish yellow. Clothed with a few outstanding pale yellow hairs, and very short, fine, sparse, decumbent little yellow hairs. The sculpturation consists of the usual fine reticulation and small puncuters.

The head is narrower and not so massive as in the typical form, more narrowed in front, not so broad and more abruptly rounded behind eyes; mandibles less massive. Thorax narrower, not so robust, more rounded in front and narrowed behind, shoulders quite round; promesonotal suture less deep and broad, no trace of mesoepinotal suture; epinotum entirely unarmed. The scale of the petiole is considerably narrower than in rastellata, the sides are straight, and there are no teeth to the external angles; two extremely small, short, pointed teeth are present in middle of upper border, another close together, the space between being slightly sinuate.

Long. 6 mm.

Type Material

PHILIPPINES, Luzon, Baguio, 28-FEB-1920, col. A. Moore. Syntype workers from The Natural History Museum - as reported by Kohout (2006).