Springtail genera/species to know in the

Entomobryomorpha

Peter Shaw

Introduction

• Entomobryomorpha are “typical” springtails and generally have a well developed furca. If you see some in your garden or pitfall traps without a lens it’s usually this group!

• They are further subdivided into those where body segments are about equal length (Isotomidae = equally cut), and those where abd 3 or 4 is enlarged reflecting large muscles (Entomobryidae).

Equal length Unequal length – abd 4 enlarged

Genera in the Entomobryidae

• Generally large with ciliated macrochaetae and well developed furca. Some have scales.

Tomocerus, etc• It used to be simple – a very big scaly springtail with ant3 elongated and

annulated was Tomocerus, and for me always will be. (6 eyes, oddly). Then someone removed the biggest of all, T. longicornis, to the genus Pogonognathellus.

Tomocerus sp – note long ant. III. In this genus ant3 hardly tapers at all and hs no scales.

6 eyes on TomocerusThe furcula lies in a

groove in the abdomen

Tomocerus minor and vulgaris

Tomocerus minor, <= 4.5mm with an irridescent blue sheen. I found this all over St Helena, presumably introduced by humans.

T. minor was once “tridentifera” due to distinctive tridentate teeth at base of furca.

T. vulgaris looks similar, but has simple teeth here.

Both lack empodial filament

Pogonognathellus longicornis

(<= 6mm, with <=8mm antennae – our largest springail). Note lyre-like curving of antennae, diagnostic of the species. Blow on them in the field!

This species is easily told from Tomocerus by microscopic examination of the foot – the empodium has a long filament. Also antenna 3 tapers and carries micro-scales. Formally the labium has a complex ciliated field (‘bearded jaw’), along with the scarce species P. flavescens).

Pogonognathellus longicornis (next to Megalothorax minimus)

Entomobryas

These are hairy but scale-less, often boldly marked, active collembola running around on bark or posts.

E. albocincta – mainly in canopy

E. intermediaE. nivalis

E. multifasciata

- stripy!

E. nicoleti

Note the paired spots)

Lepidocyrtus

Lepido = scaly, and they are! The scales are so thick on some as to give them an iridescent sheen, a bit like living drops of mercury. They jump well too.

Lepidocyrtus cyaneus – very common in litters and on surfaces. <=1.5mm.

Lepidocyrtus probably lignorum (based on rainbow patterns on ant1-2 and legs)

Lepidocyrtus lanuginosus– very common in canopy communities, also litters.

Lepidocyrtus paradoxus – note the prominent Th2.

OrchesellaAs adults these are easily spotted by the 2 basal antennal segments being doubled, giving the appearance of 6 segments.

There are 2 big very common species: Orchesella cinta (= “belted”, white abd2 vs black abd3), and O. villosa (an Entomobrya-like pattern but huge hairs). Another 5 species (?), probably scarce, ID by colour pattern.

Orchesella cinta

O. villosa

Genera in the Isotomidae

• Generally smaller with smooth macrochaetae [not all] and shorter furca; never any scales.

Parisotoma notabilis

• Everywhere all the time, all over europe too.

0.1-2.0 mm long, the giveaway is the square dot of an eyepatch with 4 ocelli.

Isotoma, s. lat.This genus has been split down into Isotoma, Desoria, and Paraisotoma. They all look pretty similar, and a few of species have the habit of turning up in ridiculously disparate habitats. About 10 other species too. Big Isotomas have ciliated macrochaetae and can be mistaken for entomobryids.

Isotoma viridis (and I. anglicana, and I. caerulea). These 3 are told apart by ridges (1 or 2) on the manubrium and hairs (2 or 3) at the base of the dens. Collectively ubiquitous. Viridis means green, but can also be shades of red/brown/grey.

Isotoma viridis, 3mm

Parisotoma notabilis – distinctive square eye patch / 4 eyes. Clonal? 4 gene lines in UK (at least!)

VertagopusTake a small grey/brown Isotoma, give it clubbed hairs (tenant setae) on its legs and make it a keen tree climber, and you’ve got a Vertagopus! 2 species, both common but only near the ground in low habitats like lichen heath.

(Flickr: Andrew Robertson)

These have a thick waxy cuticle, that can give good iridescence in the correct lighting.

Vertagopus arboreus.

Vertagopus cinerea is browner with a shorter furca.

Take an Isotoma viridis -like animal, give it trichobothria on its abdomen and a love of water, and you have Isotomurus. (The mucro looks a bit different too).

Isotomurus palustris – exceedingly common

Isotomurus maculatus

trichobothria

4 mucronal teeth

TetracanthellaI associate the upland species in this genus with my PhD in Northumberland; Tetracanthella wahlgreni an ice age relic. Blue-black with 4 orange spines on abd 6. Have since collected from pennines and Cairngorms – am always pleased to see them. Other species in moss on walls / trees but always scarce.