The Ants of Africa
Genus Crematogaster - Subgenus Sphaerocrema
Genus Crematogaster Introduction

Subgenus Sphaerocrema Santschi (1918d: 182)

Diagnostic Features - Antennae 11-jointed. Frontal carinae well developed. Petiole broadened in front, trapezoidal, sometimes truncated or rounded at the anterior angles. Postpetiole entire and without a median furrow.

Santschi's (1918d) subgenus description is at {original description}.

Key to Workers - not fully dichotomous in the old tradition but separations split to groups of relatively similar morphology and colour

Crematoagster lamotteiWorkers poorly defined and apparently consisting of a mixture of species - type similar to kneri but varieties in striatula group (see striatula below)
Guinea - lamottei
. Long headed queens (cf Cr. wellmani) -
Queen only - no images available but may well be synonymous with angusticeps
Mali - longiceps
{Crematogaster angusticeps}Queen only; TL 7.5 mm, with elongated rectangular head; propodeum unarmed but with distinct angle at transition from dorsum to decilivity (transition simply rounded on the queen of wellmani); testaceous red with the legs lighter and the gaster blackish brown; photographs on species page
Mali - angusticeps
{Crematogaster stenocephala}Queen only; head narrower than angusticeps; other characters similar - no photographs available
Senegal - stenocephala
. -
1 Propodeum with spines absent or reduced to tubercles 2
-- Propodeum with distinct spines 4
2 TL 3.8-4.0 mm; propodeum with denticles; colour generally black, appendages red-brown; head wider than long Equatorial Guinea - microspina
-- Colour orange-brown darkening posteriorly but not black; head longer than wide 3
3 {Crematogaster wellmani}TL 3.0-5.0 mm; propodeum with rounded tubercles; colour darkening posteriorly from orange-red head to brown gaster; Pan-African - wellmani
-- {Crematogaster pseudinermis}TL 2.5-3.75 mm; propodeum with tubercles sharper and a distinctive large bordered spiracle; colour brownish-yellow, gaster darker North-east Africa - pseudinermis
return to list Propodeum with distinct spines -
4
Peropodeal spines short and triangular
5
--
Propodeal spines long and sharp
6
5 {Crematogaster gambiensis}TL 2.8-4.5 mm; propodeal spines stout and fairly blunt: essentially shiny with clypeus smooth and with an arcuate anterior margin; colour reddish-brown, gaster darker Pan-African - gambiensis
-- {Crematogaster hemiceros}TL 3.7-4.0 mm; head rectangular; eyes only about one-fifth of head length and set behind the mid-point; scape surpasses occiput by about twice its own width; propodeal spines slender and short, only about a third or quarter the interval between their bases; lateral mesonotum densely reticulo-punctate; anterior of pronotum dorsum with coarse irregular striations, finer more posteriorly, rest of insect smooth; gaster with quite long moderately abundant pubescence; colour black or blackish-brown, appendages lighter Zimbabwe - hemiceros
-- Crematogaster wilnigerTL 2.0-2.1 mm; head as long as wide, sides moderately arcuate; eyes fairly convex, occupying the third quarter of the head but relatively small; scape slightly surpassing the occiput; metanotal declivity steep but metanotal groove shallow; weakly sculptured and slightly dull; colour uniform red-brown; separable from Crematogaster nigeriensis by the large subpetiolar spine, erect hairs on the pronotum and longitudinal striation on the dorsum and sides of the propodeum Congo Basin - wilniger
-- {Crematogaster paolii}TL 4.5-5.3 mm; scape surpassing occiput by about its maximum width; dorsum of alitrunk with strong longitudinal rugae, running right back to rear of propodeum; colour testaceous red, gaster slightly darker Somalia & Sudan - paolii
-- {Crematogaster nigeriensis}TL 2.3-4.5 mm; head as long as wide, sides moderately arcuate; eyes fairly convex, occupying the third quarter of the head but relatively small; scape slightly surpassing the occiput; metanotal declivity steep but metanotal groove shallow; propodeal spines about as long as one-third the spaces between the bases, horizontal with a large basal spiracle; a pair of erect hairs on each node of the pedicel; pubescence sparse short slightly raised on the thorax; smooth and shiny; colour red-brown with head and postpetiole darker, gaster brown-black with base more or less yellow-brown West Africa - nigeriensis

Propodeal spines long and sharp

6
Promesonotum concave 7
-- Promesonotum flat or convex 8
7 {Crematogaster concava}TL 3.0-3.75 mm; head near square in full face view; scape surpassing the occiput; pronotal dorsum distinctly concave; metanotal groove deep; propodeal spines long, sharp and distinctly divergent; colour chestnut brown, head and gaster very dark West Africa & Congo Basin - concava
. {Crematogaster lotti} (also, possible junior synonym lotti from Sudan)
Promesonotum flat or convex -
8
Promesonotum distinctly convex - 9
--
Promesonotum flat 12
9 Base colour red-brown - 10
--
Base colour - brown-black 11
10 {Crematogaster similis}TL 4 mm; not obviously differing from above two other than somewhat larger and darker brown CAR & Eastern Zare - similis
-- Crematogaster juventaTL 2.7-3.0 mm; head square, very slightly longer than wide; scape reaching occiput; eyes slightly convex, about one-fifth of head and placed behind the mid-line; pronotum slightly concave (less than concava); head shiny very finely striate on gena; rest of body mostly smooth; few erect hairs but decumbent pubescence quite abundant, dense and erect on antennae; colour yellow brown, occiput darker, gaster blackish in posterior half Zare - juventa
.
The following may all be forms of striatula - with at least the apical segments of the funiculus yellow contrasting with the dark scape and head
.
-- TL at least 3.5-3.8 mm = major workers?
11
-- Crrematogaster fauconnetiTL 2.7 mm; pronotum with fine but distinct median longitudinal carina; propodeal spines long but quite thick with distinct down curve; petiole quite short, as hemiceros; very dark northern Congo Basin - fauconneti
11 {Crematogaster horatii}TL ca. 4.0; head large, sides arcuate, in profile anterior strongly domed; scapes relatively thick; promesonotum forming a single dome; promesonotal suture distinct; metanotal groove wide and deep; propodeal spines slightly downcurved; distinct spiculation on lateral mesonotum; colour very dark red-brown, dark rust-red Kenya & CAR - horatii
-- {Crematogaster striatula}TL 3.0-3.5 mm; head and lateral alitrunk finely but densely striate; appendages distinctively paler yellowish; propodeal spines moderately long and sharp, with a distinct downturn; Congo specimens darker and somewhat larger; usually with distinctive, contrasting, yellow apex to funiculus; larger workers have a square head
Pan-African - striatula
-- Crematogaster phoenixTL 3.5-3.8 mm; eyes occupy more than the third quarter of the head; propodeal spines slender throughout, slightly upcurved; in dorsal view postpetiole almost square; head matt, densely and finely striate except on the occiput; colour black; ends of tarsi and antennae rust-brown
? = striatula major worker
Tanzania - phoenix
-- Crrematogaster nigransTL 3.5-4.2 mm; seems likely to be synonymous with phoenix; if so this is the senior name northern Congo Basin - nigrans
-- {Crematogaster zonacaciae}TL 4.0-4.2 mm; eyes set behind mid-point of head, frontal carinae reaching level of eyes; head with distinct median furrow; propodeal spines narrow & acute but seemingly shorter; petiole from above with convex lobate sides, 1.5 x wider than long; sub-lucid, anterior of head shiny, rest striato-punctate; castaneous, appendages brown (the MCZ cotype has yellow funiculi) - may be a junior synonym of striatula Southern Sudan - zonacaciae

Promesonotum flat

12 Heavily sculptured, with distinct striations on head, and long propodeal spines
13
--
Not heavily sculptured
14
13 {Crematogaster rugosa}TL 3.5 mm; propodeal spines very long and splayed out seen from above; petiole of distinct narrow shape; with strong rugose sculpturation on dorsal alitrunk; colour brown-black, base of gaster lighter West Africa & Congo Basin - rugosa
--
Crematogaster gerardiTL 5 mm; alitrunk densely spiculat not striated; red brown darkening from head to gaster
East Africa - gerardi
14
Propodeal spines moderate and slightly raised in profile
15
--
Propodeal spines long and flat in profile
16
15 {Crematogaster bequaerti Nigeria form}TL 3.0 mm; pronotum flat to slightly convex; metanotal groove not impressed; petiole spines straight, moderately long and flat; subpetiolar spine short and blunt; head very finely longitudinally striate; colour brown, shiny (type specimen dull); gaster with semi-decumbent hairs on first tergite
West African - dakarensis
-- {Crematogaster bequaerti}TL 4-6.3 mm; HW > HL; propodeal spines very long, about 1.5 X length of propodeum dorsum; head, alitrunk and pedicel mat, densely reticulate-punctate; slightly brownish-red, gaster blackish
Pan-African - bequaerti type form
-- {Crematogaster wilverthi}TL 2.8 mm plus; head very finely and densely striate, with distinct but small hair pits, as is thorax; propodeal spines quite robust longer than the propodeal dorsum, divergent and a little recurved; petiole with small anterior ventral tooth; colour varying from brownish-yellow to darker yellow-brown; posterior border of gaster segments with a blackish border Congo Basin - wilwerthi
-- {Crematogaster rugosior}TL 3.4-3.8 mm; close to luctans; head wider than long; scape slightly surpassing the occiput; propodeal spines more slender and closer together; shiny but sculpturation of most of body more strongly striated; colour brown more or less with reddish tinge; posterior border of gaster segments yellowish Congo Basin - rugosior
.
Propodeal spines long and flat
.
16
Base colour yellow or yellow-brown
17
--
Base colour red-brown or darker
18
17 {Crematogaster zavattarii}TL 3.0-3.8 mm; unusually convex eyes; scape quite thick and distinctly wider apically; propodeal spines long, acute and divergent but near horizontal in profile; colour piceous (?, original description, darker than striatula), funiculus and tarsi rust; pubescence pallid West Africa & Congo Basin - zavattarii
-- Crematogaster luctansTL 2.5-3.3 mm; kneri group but pronotum shorter and wider; scapes shorter; anterior margin of clypeus weakly impressed; occipital margin weakly impressed; dorsum of propodeum short, spines more robust; pronotal dorsum weakly but distinctly sculptured; colour ferruginous-red or yellower, basal segment of gaster clear brown, rest darker but segments with narrow yellowish borders West Africa, Congo Basin, Kenya - luctans
-- Crematogaster chloroticaTL 3.0-3.5 mm; close to kneri but head and pronotum mostly smooth and shiny; colour testaceous yellow with apex of abdomen blackish West Africa & Congo Basin - chlorotica
-- Crematogaster kneri typeTL 4.0 mm; head rounded slightly wider than long; pro- and mesonotum marginate laterally; sculpturation of fine reticulation with overlying rugulation on anterior head and alitrunk; propodeal spines long and acute; colour yellowish, gaster darker
type form
Pan-African - kneri
--
Crematogaster pronotalisTL ca 4.8 mm; dark yellow brown
Senegal to Congo Basin - pronotalis
--
Crematogaster liebknechtiTL 3.4-3.6 mm; shiny
Congo Basin - liebknechti

Base colour red-brown or darker

18 Crematogaster hottentotaTL 3.0-3.9 mm; propodeal spines horizontal and short; head smooth and shining with only fine striation on anterior; head and thorax variably dull yellow, gaster dark brown; cf kneri South Africa - hottentota.
-- {short description of image}TL 3.7 mm; eyes occupy about the third quarter of the head; promesonotal suture very deep, pronotum convex but mesonotum flat; propodeal spines about as long as the propodeum dorsum slightly raised and divergent; head finely and densely striate longitudinally; thorax with short longitudinal rugae with interspaced rugo-reticulation; lateral alitrunk densely striate; colour reddish-brown; mandibles, funiculus and articulations of scape and tarsi clear rust, rest of scape tarsi and petiole more brown Uganda - rustica
-- {short description of image}TL 3.5-4.3 mm; promesonotal suture distinct (deeper than in kneri); mesonotum with distinct median carina; colour dark-brown, base of gaster paler; appendages paler to reddish-brown; Tanzania & Zimbabwe - amita
-- {short description of image}TL 4.5 mm; not very obviously different to gabonensis, but head seemingly rather narrower; type with a dark brown head Congo Basin (& West Africa?) - libengensis
-- {Crematogaster gabonensis}TL 4.5 (holotype); head large, sides arcuate; promesonotum forming a single dome; promesonotal suture distinct; metanotal groove wide and deep; propodeal spines flat and sharp as long as propodeum dorsum; colour dark rust-red, gaster pitch brown West Africa & Congo Basin - gabonensis

Crematogaster (Sphaerocrema) near kneri

Eight workers were found by Majer (1976b) in a pkd sample at Kade in Ghana.


Crematogaster (Sphaerocrema) near striatula

This was listed from Ghana by Bigger (1993b), who recorded it as a sub-dominant on his study Block of Amazon cocoa at CRIG, in 1969-76. He noted that it was not as aggressive as Crematogaster striatula. It seems likely to be the same as Crematogaster species F 361, which was described by Strickland (1951a) as probably a variety of Crematogaster striatula, less common at CRIG but almost identical in habit.


Crematogaster (Sphaerocrema) undet. Bernard list

From Guinea, Mt. Nimba, Station T 44, Nion, several workers (Lamotte), plus others from leaf litter in the north-east forest (Villiers), defined by Bernard (1952) as soft and immature, therefore not certainly identifiable, although of the nigrans-lamottei group.

Contents MYRMICINAE Introduction
2007, 2008, 2009, 2010, 2011, 2013, 2015, 2016, 2017, 2018 - Brian Taylor CBiol FRSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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