Order Archaeognatha

Also spelled Archeognatha. In Borrer et al., referred to as Microcoryphia.

1. Jumping Bristletails
2. Archaeognatha: primitive Order whose members were assigned to the Thysanura.
3. Scientific name (archaeo = old; gnatha = jaw) refers to primitive condition of mandible articulation. (Greek, micros = small; corpyphia = head).
4. Common name refers to the long cerci and appendix dorsalis.
5. Fossil: Triassic deposits in Russia (Triassomachilidae).

Archaeognatha Anatomy

1. Body moderate to large sized (7-18mm)
2. Laterally compressed
3. Covered with scales.

Head

1. Hypognathous
2. Compound eyes well developed, fused in midline dorsally.
3. Ocelli present.
4. Mandible monocondylic (= having a single point of articulation). This is a primitive condition; all other insect orders have dicondylic mandibles
5. Maxillary palps 7-segmented.

Thorax

1. Arched.
2. Coxal styli present - indicates primitive condition
3. Tarsi 2 or 3-segmented, pretarsus with 2 claws.

Abdomen

1. 11-segmented
   • a. Terga large
   • b. Sterna small in Australian species
2. Styli on segments 2-9 (G & C p. 47,48 [new edition - 39,40)
3. Eversible water absorbing vesicles on segs 1-7, at base of abdominal styli.
4. Cerci filiform
5. Appendix Dorsalis longer than cerci.
6. Jump by rapid flexion of abdomen.
7. Ovipositor well developed, long, slender.

Archaeognatha Biology & Ecology

Biology

1. Feed on algae, moss and other plant material.
2. No mating; courtship "dance" in some
   • Transfer of sperm indirect, stalked spermatophore in Aust. spp.
   • Deposition of stalked spermatophore on ground, similar to many Collembola
   • Larval development ametabolous. Immatures distinguished from adults by smaller size and absent or small genitalia.
   • Sexual maturity attained at 8th or 9th instar, after 3 months to 1 year.
3. Moulting continues after adult ecdysis: long lived: 2-4 years
4. Some species may have some degree of sociality

Ecology

1. Found under bark, stones and in grass or leaf litter.
2. Typically nocturnal.
3. Abdominal styli: used in locomotion.
4. Some live near sea-shore, can jump up to 10 cm.

thanks to University of Queensland

• NCSU
• Archeognatha - Discoverlife