European Journal of Taxonomy 90: 1-16

http://dx.doi.org/10.5852/ejt.2014.90

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ISSN 2118-9773

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2014 • Hita Garcia F. & Fischer G.

Research article

urn:lsid:zoobank.org:pub:ABE983B7-AA93-45B9-A308-BDC0FE5805A3

Additions to the taxonomy of the Afrotropical Tetramorium weitzeckeri

species complex (Hymenoptera, Formicidae, Myrmicinae), with the

description of a new species from Kenya

Francisco HITA GARCIA 1 A * & Georg FISCHER 24

Entomology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco,

CA 94118, U.S.A.

* Corresponding author: fhitagarcia@gmail. com

2 Entomology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco,

CA 94118, U.S.A.

Email: georgfS l@gmail com

3 urn:lsid:zoobank.org:author:B7ADF56F-935D-4BD8-ADB3-50E96F8BB463

4 urn:lsid:zoobank.org:author:16CEBC67-ECE7-4FC4-B537-085F0E26E85A

Abstract. This study presents a taxonomic update of the Tetramorium weitzeckeri species group.

Tetramorium mpala sp. nov. is described from Laikipia, Kenya, and placed in the T. weitzeckeri species

complex. In addition, we also provide an illustrated identification key to the three species complexes

of the T. weitzeckeri species group, and an updated illustrated identification key to the species of the

T. weitzeckeri species complex.

Keywords. Kenya, Laikipia, Mpala Research Centre, taxonomy, Tetramoriini

Hita Garcia F. & Fischer G. 2014. Additions to the taxonomy of the Afrotropical Tetramorium weitzeckeri species

complex (Hymenoptera, Fonnicidae, Myrmicinae), with the description of a new species from Kenya. European

Journal of Taxonomy 90: 1-16. http://dx.doi.org/10.5852/eit.2014.9Q

Introduction

The globally occurring myrmicine genus Tetramorium Mayr, 1855 is widespread throughout all zoogeo-

graphical regions and can be considered as hyper-diverse, with currently more than 545 valid species

(Bolton 2013). It is a predominantly Old World genus with very few, mostly introduced, species found

in the New World (Brown 1957; Bolton 1976, 1977, 1979, 1980; Hita Garcia et al. 2010). Its main

distribution, with ca. 230 described species, lies in the Afrotropical region, where species of Tetramorium

occupy a wide range of habitats, microhabitats and lifestyles not seen in any other region, which

suggests a likely origin or diversification centre within the Afrotropical region (Bolton 1976, 1980; Hita

Garcia et al. 2010). The Malagasy Tetramorium fauna also shows a high degree of diversity, endemism,

and often micro-endemism along its numerous isolated mountain ranges, but is less species-rich and

holds much less morphological and ecological diversity than that of the Afrotropics. The combined

and ongoing efforts of exhaustive inventories and large-scale revisions recently elevated the diversity

in the Malagasy region from 39 species (Bolton 1979) to ca. 125 species (Hita Garcia & Fisher 2011,

2012a, 2012b; FHG unpublished data). Due to its global distribution and hyper-diversity, new species of

European Journal of Taxonomy 90 : 1-16 ( 2014 )

Tetramorium are continuously being discovered and described on a global level (e.g., Europe: Czosz et

al. 2007; Csosz & Schulz 2010; Central America: Vasquez-Bolanos 2007; Vasquez-Bolanos etal. 2011;

Saudi Arabia: Sharaf et al. 2012; India: Bharti & Kumar 2012), but the bulk of the undescribed diversity

is expected from the Afrotropical region. Even though Bolton (1980) revised the whole Afrotropical

region and synonymized the former genus Triglyphothrix Forel, 1890 with Tetramorium (Bolton 1985),

many undescribed species have been discovered in field studies and in a score of museum collections by

the authors (Hita Garcia et al. 2009, 2010, 2013, unpublished data). The taxonomy of two Afrotropical

species groups was revised in recent years. In the first study twelve out of 26 species of the T. weitzeckeri

group were described as new species (Hita Garcia et al. 2010), while the second described one additional

species of the T. tortuosum group, raising the African species count to three (Hita Garcia & Fisher 2013).

With on-going taxonomic research and with additional material of undescribed species being generated

by numerous field studies, we expect that the diversity of Tetramorium in the Afrotropical region is

likely to reach 350 to 400 species in the future.

In 2009 and 2010 during the revision of the T. weitzeckeri species group (Hita Garcia et al. 2010) we

became aware of a potentially new species collected by the late Roy R. Snelling (Natural History Museum

of Los Angeles County, Los Angeles, U.S.A.) in Laikipia, Kenya (R.R. Snelling unpublished notes).

Snelling wrote in his notes about a new species commonly collected on the ground at Mpala Research

Centre, which looked morphologically very close to T. weitzeckeri Emery, 1895 and T. guineense

(Bernard, 1953) but differing from them in petiolar node shape and pilosity on the first gastral tergite.

During a research visit to the Snelling collection in 2009 we tried to find this material, which supposedly

consisted of a few collections from the ground at Mpala Research Centre. Unfortunately, even after a

thorough search through the collection, there was no undescribed T. weitzeckeri group species from

Laikipia to be found anywhere, and the revision of the species group was finished without including

that mysterious species. Surprisingly, during a recent examination of unidentified general Kenyan ant

material collected by Snelling in 2001 at Mpala Research Centre, we encountered one specimen from

an undescribed species belonging to the T. weitzeckeri species group. After a first examination it became

apparent that it was indeed the new species mentioned by Snelling in his unpublished notes.

In this study we describe that new species as Tetramorium mpala sp. nov. and integrate it into the

existing taxonomic system of the T. weitzeckeri species complex/group. Accordingly, we provide

an illustrated identification key to the three species complexes of the T. weitzeckeri species group

(T. edouardi complex, T. muralti complex, T. weitzeckeri complex) and an updated illustrated

identification key to the species of the T. weitzeckeri species complex.

Material and methods

The collection abbreviations follow Evenhuis (2013). The material upon which this study is based is

located and/or was examined at the following institutions:

BMNH

CASC

LACM

MCZ

MHNG

NHMB

ZFMK

The Natural History Museum (British Museum, Natural History), London, U.K.

California Academy of Sciences, San Francisco, California, U.S.A.

Natural History Museum of Los Angeles County, Los Angeles, California, U.S.A.

Museum of Comparative Zoology, Cambridge, Massachusetts, U.S.A.

Museum d’Histoire Naturelle de la Ville de Geneve, Geneva, Switzerland

Naturhistorisches Museum, Basel, Switzerland

Zoological Research Museum Alexander Koenig, Bo nn , Germany

The only available specimen of T. mpala sp. nov. was deposited in the collection of LACM. Most of the

material used for the recent revision of the whole T. weitzeckeri species group (Hita Garcia et al. 2010),

especially the most recent collections, can be found in the collections of BMNH, CASC, LACM and

ZFMK, while older type material is mostly located at BMNH, MCZ, MHNG and NHMB. The new type

HITA GARCIA F. & FISCHER G., Taxonomy of the Afrotropical Tetramorium weitzeckeri complex

and all imaged specimens can be uniquely identified with specimen-level codes affixed to each pin (e.g.,

CASENT0247445).

Digital colour images of the new species were created using a Leica DFC 425 camera in combination

with the Leica Application Suite software (version 3.8). All images presented are available online and

can be consulted on AntWeb ( http://www. antweb.org ) . The measurements were taken with a Leica MZ

12.5 equipped with an orthogonal pair of micrometers at a magnification of 100x. Measurements are

expressed in mm to two decimal places. The measurements and indices used in this study follow Hita

Garcia & Fisher (2011, 2012a, 2012b, 2013):

PSL

PTH

PTL

PTW

PPH

PPL

PPW

Head length: maximum distance from the mid-point of the anterior clypeal margin to the

mid-point of the posterior margin of the head, measured in full-face view. Impressions on

anterior clypeal margin and posterior head margin reduce head length

Head width: width of head directly behind the eyes measured in full-face view

Scape length: maximum scape length excluding basal condyle and neck

Eye length: maximum diameter of compound eye measured in oblique lateral view

Pronotal height: ma xim um height of pronotum measured in lateral view

Pronotal width: maximum width of pronotum measured in dorsal view

Weber’s length: diagonal length of mesosoma in lateral view from the postero-ventral

margin of the propodeal lobe to the anterior-most point of the pronotal slope, excluding the

neck

Propodeal spine length: the tip of the measured spine, its base, and the centre of the

propodeal concavity between the spines must all be in focus. Using a dual-axis micrometer

the spine length is measured from the tip of the spine to a virtual point at its base where the

spine axis meets orthogonally with a line leading to the median point of the concavity

Petiolar node height: maximum height of petiolar node measured in lateral view from the

highest (median) point of the node to the ventral outline. The measuring line is placed at an

orthogonal angle to the ventral outline of the node

Petiolar node length: maximum length of the dorsal face of the petiolar node from the

anterodorsal to the posterodorsal angle measured in dorsal view

Petiolar node width: maximum width of dorsal face of petiolar node measured in dorsal

view

Postpetiole height: maximum height of the postpetiole measured in lateral view from the

highest (median) point of the node to the ventral outline. The measuring line is placed at an

orthogonal angle to the ventral outline of the node

Postpetiole length: maximum length of postpetiole measured in dorsal view

Postpetiole width: maximum width of postpetiole measured in dorsal view

OI = Ocular index (EL / HW x 100)

Cl = Cephalic index (HW / HL x 100)

SI = Scape index (SL / HW x 100)

DMI = Dorsal mesosoma index (PW / WL x 100)

LMI = Lateral mesosoma index (PH / WL x 100)

PSLI = Propodeal spine index (PSL / HL x 100)

PeNI = Petiolar node index (PTW /PW x 100)

LPel = Lateral petiole index (PTL / PTH x 100)

DPel = Dorsal petiole index (PTW / PTL x 100)

PpNI = Postpetiolar node index (PPW / PW x 100)

LPpI = Lateral postpetiole index (PPL / PPH x 100)

DPpI = Dorsal postpetiole index (PPW / PPL x 100)

PPI = Postpetiole index (PPW / PTW x 100)

European Journal of Taxonomy 90: 1-16 (2014)

Note that the petiole and postpetiole were measured differently. For the petiole, only the petiolar node

was measured, excluding the peduncle, as the node has proved to be of high diagnostic value (Hita

Garcia et al. 2010). Measurements of the whole petiole, peduncle plus node, would mask these important

differences between species. In contrast, we measured the whole postpetiole because it was rounded in

most species and without a distinct peduncle-like structure. As a consequence, some information can be

lost in the few species with a moderately or strongly anteroposteriorly compressed postpetiole. Even so,

the postpetiole measurements as defined still permit better comparisons for most species.

Pubescence and pilosity are usually of high diagnostic value within the genus Tetramorium (e.g., Bolton

1976, 1980; Hita Garcia et al. 2010, Hita Garcia & Fisher 2011, 2012a, 2012b). The varying degree of

inclination of pilosity is particularly important for the diagnoses of groups or species. In this context

we use the terms ‘erect’, ‘suberect’, ‘subdecumbent’, ‘decumbent’, and ‘appressed’ following Wilson

(1955).

Results

Identification key to Afrotropical species complexes of the T. weitzeckeri species group (workers)

In Hita Garcia et al. (2010) we provided a key to all species from all three species complexes without a

special key to these complexes. In order to facilitate species identifications and species group placements

in the future, we provide a simple key to the complexes here:

1. Antennal scrobe well developed and usually deep, with a distinct and often sharp margin all around,

frontal carinae curve down ventrally between posterior eye level and occipital margin to form the

posterior and ventral margins of the antennal scrobe, in a few species posterior margin weak but still

Fig. 1 . Head in frontal and lateral views. A, E. Tetramorium flavithorax (Santschi, 1914) (ZFMK-

HYM20096172). B, F. T. muralti Forel, 1910 (ZFMKHYM20096125). C, G. T. weitzeckeri Emery

(CASENT0249013, AntWeb, R. Perry 2011). D, H. T. mkomazi Hita Garcia, Fischer & Peters, 2010

(ZFMKHYM20096087).

HITA GARCIA F. & FISCHER G., Taxonomy of the Afrotropical Tetramorium weitzeckeri complex

visible; sculpture on cephalic dorsum often reduced, generally 3 or fewer rugae present between

frontal carinae, in a few species up to 5 or 6, never more (Fig. 1A-B, E-F). T. muralti complex

Antennal scrobe developed, but shallow, never with a sharp margin all around, frontal carinae almost

reaching occipital margin and functioning as dorsal margin of antennal scrobe, ventral margin of

antennal scrobe never differentiated; sculpture on cephalic dorsum never reduced, always at least 7

(generally distinctly more) longitudinal rugae present between frontal carinae (Fig. ID, G-H).2

2. Petiolar node distinctly squamiform, in profile between 2.3 and 4.0 times higher than long

(LPel 25-43), shape in dorsal view always strongly transverse and elliptical, and between 2.2

and 3.7 times wider than long (DPel 219-367) (Fig. 2A-B, E-F) . T. weitzeckeri complex

Petiolar node high nodiform, in profile around 1.3 to 2.0 times higher than long (LPel 50-80), shape

in dorsal view never elliptical or transverse, more an irregular polygon with rounded corners, and

between 1.1 and 1.5 times wider than long (DPel 110—154) (Fig. 2C-D, G-H) T. edouardi complex

Synopsis of Afrotropical T. weitzeckeri species complex

Tetramorium bendai Hita Garcia, Fischer & Peters, 2010

Tetramorium boltoni Hita Garcia, Fischer & Peters, 2010

Tetramorium guineense (Bernard, 1953)

Tetramorium humbloti Forel, 1891

= Tetramorium humbloti pembensis Forel, 1907

= Tetramorium humbloti victoriensis Forel, 1913

Tetramorium mpala Hita Garcia & Fischer sp. nov.

Tetramorium renae Hita Garcia, Fischer & Peters, 2010

Tetramorium sepultum Bolton, 1980

Tetramorium snellingi Hita Garcia, Fischer & Peters, 2010

Fig. 2. Petiolar node in lateral and dorsal views. A, E. Tetramorium renae Hita Garcia, Fischer &

Peters (CASENT0095412). B, F. T. bendai Hita Garcia, Fischer & Peters (ZFMKHYM20096204).

C, G. T. philippwagneri Hita Garcia, Fischer & Peters, 2010 (ZFMKHYM20096178). D, H. T. mkomazi

Hita Garcia, Fischer & Peters, 2010 (ZFMKHYM20096087).

European Journal of Taxonomy 90 : 1-16 ( 2014 )

Tetramorium tanaense Hita Garcia, Fischer & Peters, 2010

Tetramorium weitzeckeri Emery, 1895

= Tetramorium ebeninum Arnold, 1926

= Tetramorium escherichi Forel, 1910

= Tetramorium weitzeckeri edithae (Weber, 1943)

= Tetramorium weitzeckeri nigellus (Santschi, 1932)

Notes on biogeography and identification

New material has become available since the last revision of the T. weitzeckeri species group (Hita

Garcia et al. 2010); subsequently, the distribution ranges of a few species need to be adjusted. Fresh

material from an ongoing inventory of the ant fauna of Gorongosa National Park in Mozambique

revealed the presence of T. humbloti , T. sepultum and T. weitzeckeri. Even though their presence in

Mozambique is not surprising, all three were previously unknown from that country. Hita Garcia et al.

(2010) reported the absence of T. humbloti from Kenya, but some freshly identified material from the

area around Nairobi clearly belongs to this species. The distribution range of T. tanaense is also larger

than previously understood. It is now known from the forest of Arabulco Solcoke on the Kenyan coast,

which is close to the type locality, and from Ndimba Forest Reserve located in south-eastern Tanzania

close to the Indian Ocean.

Despite these new findings, the biogeographic composition of the complex has not changed significantly.

Tetramorium boltoni, T. guineense , T. renae and T. snellingi are species found predominantly in the

equatorial rainforest belt, whereas the species T. humbloti , T. sepultum and T. weitzeckeri are distributed

in the drier eastern and southern parts of sub-Saharan Africa. Tetramorium tanaense seems to be endemic

to the coastal forests of Eastern Africa in Kenya and Tanzania, and T. bendai is only known from one

collection in Burundi (without any ecological information at all). Tetramorium mpala sp. nov. also seems

to have a very restricted distribution because it is only known from its type locality in Central Kenya.

In addition, several non-taxonomists have used the identification key published in Hita Garcia et al.

(2010) and, fortunately, provided feedback to us. The key seemed to have worked mostly well, but users

drew attention to some problems in the key not anticipated back in 2010. These problems were mainly

located in the part of the key dealing with the T. weitzeckeri species complex, especially the separation

Fig. 3. Gaster in lateral view. A. Tetramorium humbloti Forel (CASENT0059691, AntWeb, April

Nobile 2006). B. T. renae Hita Garcia, Fischer & Peters (CASENT0095412). C. T. mpala sp. nov.

(CASENT0247445, AntWeb, M. Esposito 2013).

HITA GARCIA F. & FISCHER G., Taxonomy of the Afrotropical Tetramorium weitzeckeri complex

Fig. 4. Mesosoma in lateral view. A. Tetramorium sepultum Bolton (CASENT0901160, AntWeb, W.

Ericson2011). B. T. tanaense Hita Garcia, Fischer & Peters (CASENT0235815, AntWeb, R. Perry 2011).

C. T. humbloti Forel (CASENT0900677, AntWeb, W. Ericson 2011).

of T. guineense from T. weitzeckeri. Some series of the latter species from Tanzania and South Africa

possess strongly developed cephalic ground sculpture almost as distinct as seen in T. guineense , which

causes difficulties with the key, even though both species are certainly not conspecific and differ in

various aspects. Consequently, we have modified the identification key to include these users’ first-hand

experience in order to make the discrimination of T. guineense from T. weitzeckeri easier, as well as

several other minor changes throughout the key.

Identification key to species of the T. weitzeckeri species complex (workers)

1. First gastral tergite without any form of standing pilosity (Fig. 3A) .2

- First gastral tergite with standing pilosity (Fig. 3B-C) .5

2. Mesosoma with abundant long, erect hairs (usually 7 to 8 pairs of hairs) (Fig. 4A) [Mozambique,

Tanzania, South Africa, Swaziland]. T. sepultum

Mesosoma usually without long, erect hairs, rarely with up to 4 pairs of hairs at most (Fig. 4B-C) ...3

3. Whole mesosoma covered with fine, mostly longitudinal rugulae superimposed on a very

distinct reticulate-punctate ground sculpture (Fig. 5A) [Burundi] . T. bendai

Mesosoma either mostly unsculptured or rugulose, often in parts with wealdy punctate ground

sculpture, but never fully covered with distinct reticulate-punctate ground sculpture as above (Fig.

5B-C)......4

Fig. 5. Mesosoma in dorsal view. A. Tetramorium bendai Hita Garcia, Fischer & Peters

(ZFMKHYM20096204). B. T. tanaense Hita Garcia, Fischer & Peters (CASENT0235815, AntWeb, R.

Perry 2011). C. T. humbloti Forel (CASENT0059691, AntWeb, A. Nobile 2006).

European Journal of Taxonomy 90 : 1-16 ( 2014 )

4. Most of mesosomal dorsum, especially pronotum, noticeably longitudinally rugulose (Fig. 5B)

[Kenya, Tanzania]. T. tantieme

Dorsum of mesosoma, especially pronotum, unsculptured and shiny (Fig. 5C) [Comoros, Kenya,

Madagascar, Mauritius, Mayotte, Mozambique, Namibia, South Africa, Tanzania, Zambia,

Zimbabwe]. T. humbloti

5. Eyes very large (01 31); first gastral tergite with long, decumbent to subdecumbent (rarely

appressed) pilosity [Kenya] (Fig. 6A, D) . T. mpala sp. nov.

Eyes always smaller than above (01 16-26); first gastral tergite with long suberect to erect

pilosity (Fig. 6B-C, E-F) .6

6. Dorsum of head with conspicuous reticulate-punctate ground sculpture; postpetiole in profile

between 1.3 and 1.7 times higher than long (LPpI 59-75) and in dorsal view around 1.4

Fig. 6. Half of head in frontal view and gaster in lateral view. A, D. Tetramorium mpala sp. nov.

(CASENT0247445, AntWeb, M. Esposito 2013). B, E. T. snellingi Hita Garcia, Fischer & Peters

(ZFMK-HYM20093102). C, F. T. renae Hita Garcia, Fischer & Peters (CASENT0095412).

HITA GARCIA F. & FISCHER G., Taxonomy of the Afrotropical Tetramorium weitzeckeri complex

Fig. 7. Head in frontal view and waist segments in dorsal view. A, E-F. Tetramorium guineense

(Bernard) (CASENT0217061, AntWeb, E. Prado 2011). B. T. renae Hita Garcia, Fischer & Peters

(CASENT0095412). C-D, G-H. T. weitzeckeri Emery (CASENTO103295 & CASENT0235814,

AntWeb, A. Nobile 2006 & R. Perry 2011).

to 1.5 times wider than long (DPpI 137-154) (Fig. 7A, E-F) [Cameroon, Central African

Republic, D.R. Congo, Gabon, Ghana, Guinea, Ivory Coast, Liberia, Nigeria] . T. guineense

Character combination never as above; dorsum of head usually without conspicuous reticulate-

punctate ground sculpture; if cephalic ground sculpture noticeably reticulate-punctate (as in some

series of T. weitzeckeri ), then postpetiole in profile around 1.7 to 2.1 times higher than long (LPpI

49-60) and in dorsal view 1.7 to 2.0 times wider than long (DPpI 146-203) (Fig. 7B-D, G-H).7

7. Distinctly bicoloured species, head and mesosoma orange to reddish brown, petiole, postpetiole and

gaster very dark brown to black (Fig. 8A) [Central African Republic, Kenya, Uganda] ...I snellingi

Whole body either uniformly brown to black or bicoloured with gaster, and often head, of

lighter colour than mesosoma, petiole, and postpetiole (Fig. 8B-C) .8

8. Species either bicoloured, with gaster, appendages and head yellowish brown contrasting

with reddish brown mesosoma, petiole and postpetiole, or whole body dark brown to black;

mesosomal sculpture partly reduced, dorsum generally with weak longitudinal rugulae only,

Fig. 8. Body in lateral view. A. Tetramorium snellingi Hita Garcia, Fischer & Peters (ZFMKHYM-

20093102, E. Wiesel). B. T. weitzeckeri Emery (CASENTO 103295, AntWeb, A. Nobile 2006). C. T. renae

Hita Garcia, Fischer & Peters (CASENT0095412).

European Journal of Taxonomy 90: 1-16 (2014)

Fig. 9. Mesosoma in dorsal and lateral views. A, E. Tetramorium renae Hita Garcia, Fischer & Peters

- light brown form (CASENT0095412). B, F. T. renae Hita Garcia, Fischer & Peters - dark brown

form (CASENT0095421, AntWeb, W. Ericson 2011). C, G. T. weitzeckeri Emery (CASENTO103295,

AntWeb, A. Nobile 2006). D, H. T. boltoni Hita Garcia, Fischer & Peters (CASENT0217229, AntWeb,

R. Perry 2011).

lateral mesosoma to great extent unsculptured; ground sculpture on lateral and dorsal mesosoma

absent, appearing smooth and shining (Figs 8C, 9A-B, E-F) [Sao Tome & Principe]. T. renae

Uniformly coloured species, generally dark brown to black; usually with mesosoma dorsally and

laterally strongly longitudinally rugose, very rarely with weaker developed rugae or rugulae, in

the latter case the ground sculpture is reticulate-punctate (Figs 8B, 9C-D, G-H) .9

9. Larger species (HW 0.77-0.93; HL 0.79-0.94; SL 0.60-0.74; WL 0.91-1.21); propodeal

spines long to very long and spinose (PSLI 32—45); body colouration ranging from light

brown to almost black, but usually of lighter brown than below; dry forest or savannah species

(Figs 9G, 10A) [Angola, Eritrea, Kenya, Mozambique, Namibia, South Africa, Sudan,

Swaziland, Tanzania, Zambia, Zimbabwe] . T. weitzeckeri

- Smaller species (HW 0.64-0.74; HL 0.68-0.76; SL 0.47-0.54; WL 0.78-0.91); propodeal

spines moderate to long, triangular-elongate to spinose, but never as long as above (PSLI 23-

29); body colouration always very dark brown to black; rainforest species (Figs 9H, 10B)

[Angola, Cameroon, Central African Republic, D.R. Congo, Equatorial Guinea, Gabon, Kenya,

Nigeria, Uganda, Sudan] . T. boltoni

Fig. 10. Body in lateral view. A. Tetramorium weitzeckeri Emery (CASENTO 103295, AntWeb,

A. Nobile 2006). B. T. boltoni Hita Garcia, Fischer & Peters (ZFMKHYM20096155).

HITA GARCIA F. & FISCHER G., Taxonomy of the Afrotropical Tetramorium weitzeckeri complex

Tetrcimorium mpala sp. nov.

urn:lsid:zoobank.org:act:97CF15C9-2859-4075-9A6A-F0A82023BA3A

Figs 3C, 6A, D, 11, 12

Type material

Holotype

KENYA: Pinned worker, Rift Valley Province, Laikipia District, Mpala Research Centre, 0.29° S,

36.9° E, 1650 m. Acacia woodland, foraging on ground, collection code RRS01-188, 2 Apr. 2001, R.R.

Snelling, unique specimen identifier CASENT0247445 (LACM).

Diagnosis

The character combination of very large eyes (OI31) and first gastral tergite with long, fine decumbent to

subdecumbent (rarely appressed) pilosity distinguishes T. mpala from the remainder of the T. weitzeckeri

species complex.

Description (worker, N=l)

Measurements: HL 0.79; HW 0.74; SL 0.60; EL 0.23; PH 0.44; PW 0.59; WL 1.04; PSL 0.28; PTL 0.12;

PTH 0.36; PTW 0.35; PPL 0.26; PPH 0.38; PPW 0.42; Cl 94; SI 71; OI 31; DMI 57; LMI 42; PSLI 35;

PeNI 59; LPel 33; DPel 292; PpNI 71; LPpI 68; DPpI 162; PPI 120.

Head longer than wide (Cl 94); posterior head margin in full-face view flat to weakly concave; anterior

clypeal margin with distinct median impression; frontal carinae strongly developed, distinctly raised,

and very long, approaching or ending at posterior head margin; antennal scrobes present, but shallow

and without clearly defined posterior and ventral margins. Antennal scapes of moderate length, not

reaching posterior head margin (SI 81). Eyes very large (OI 31).

Mesosomal outline in profile weakly to moderately convex, moderately marginate from lateral to dorsal

mesosoma, comparatively high and stout (LMI 42); promesonotal suture present, weak but clearly

visible; metanotal groove well developed and in profile moderately deep. Propodeal spines long, spinose

and acute (PSLI 35); propodeal lobes short, triangular and blunt. Petiolar node squamiform to thinly

high cuneiform and slightly triangular, in profile three times higher than long (LPel 33), anterodorsal and

posterodorsal margins relatively rounded and posterodorsal margin less well developed than anterodorsal,

petiolar dorsum tapering backwards; node in dorsal view of strongly transverse elliptical shape, around

2.9 times as wide as long (DPel 292). Postpetiole in profile subglobular to weakly anteroposteriorly

compressed, approximately 1.5 times as high as long (LPpI 68); in dorsal view around 1.6 times as wide

as long (DPpI 162). Postpetiole in profile appearing higher and more voluminous than petiolar node, in

dorsal view 1.2 times as wide as petiolar node (PPI 120).

Mandibles striate; clypeus longitudinally rugulose with six more or less irregular rugulae, median

rugula not well developed; cephalic dorsum between frontal carinae irregularly longitudinally rugose

with around eight rugae, rugae running from posterior clypeal margin to posterior head margin, but

some broken, meandering or with cross-meshes; scrobal area partly unsculptured, but mostly merging

with surrounding reticulate-rugose to longitudinally rugose sculpture present on lateral and ventral.

Mesosoma laterally and dorsally longitudinally rugose, laterally slightly more irregularly so. Forecoxae

unsculptured, smooth and shining. Both waist segments and gaster completely unsculptured, smooth

and shining. Ground sculpture generally faint to absent everywhere on body. Head with moderately

abundant standing pilosity; mesosoma with six pairs of long, fine, standing hairs; petiole with three pairs

of long, fine, standing hairs and postpetiole with four pairs of subdecumbent to decumbent, long, fine

hairs; first gastral tergite with fairly long, fine and subdecumbent to decumbent pilosity. Anterior edges

European Journal of Taxonomy 90: 1-16 (2014)

Fig. 11. Tetramorium mpala sp. nov. (CASENT0316967). A. Body in lateral view. B. Body in dorsal

view. C. Head in frontal view.

HITA GARCIA F. & FISCHER G., Taxonomy of the Afrotropical Tetramorium weitzeckeri complex

of antennal scapes and metatibiae with appressed hairs. Body colouration chestnut brown to dark brown,

appendages lighter in colour and gaster much darker than remainder of body.

Etymology

The name of the new species is inspired by the type locality, the Mpala Research Centre, which is an

important research facility in Kenya. The species epithet is a nominative noun in apposition and thus

invariant.

Distribution and ecology

Tetramorium mpala sp. nov. is currently only known from the type locality (Fig. 12) where it was

collected in acacia woodland savannah at an elevation of 1650 m. The holotype was sampled on the

ground, but until more material becomes available it remains unclear whether that is the primary stratum

of T. mpala.

Discussion

The new species is readily distinguishable within the T. weitzeckeri species complex. The most obvious

character is certainly the pilosity on the first gastral tergite, which is long, fine and subdecumbent to

decumbent in T. mpala sp. nov., whereas the remainder of the complex either lacks any long pilosity

at all (I bendai, T. humbloti, T. sepultum and T. tanaense ) or possesses long, suberect to erect pilosity

(T. boltoni , T. guineense, T. renae , T. snellingi and T. weitzeckeri). The second-best character is eye size.

European Journal of Taxonomy 90: 1-16 (2014)

since T. mpala sp. nov. has the largest eyes (01 31) encountered in the species complex, which contrast

with the generally much smaller eyes of the other species (usually 0116-26, only a few specimens of T.

humbloti and all of T. tanaense have 01 27-29).

Another aspect that deserves attention here is the shape of the petiolar node in T. mpala. It is clearly

squamiform like in all species of the T. weitzeckeri complex, but also similar to the high cuneiform and

slightly triangular form found in some species of the Afrotropical T. squaminode species group (Bolton

1980) or the Malagasy T. marginatum and T. bonibony species groups (Hita Garcia & Fisher 2012a).

As already noted by Bolton (1980) and later by Hita Garcia et al. (2010), there seems to be a close

relationship between the 11-segmented T. weitzeckeri group (especially the T. weitzeckeri complex)

and the 12-segmented T. squaminode group, mainly on the basis of the spatulate sting appendage

and the squamiform petiolar node. T. mpala sp. nov. appears to be an additional argument for a close

relationship between these groups since its petiolar node shape is intermediate. However, at present,

without a taxonomic revision of the T. squaminode group and a broader phylogenetic analysis of the

genus Tetramorium as a whole, we prefer to keep these groups separate.

Unfortunately, the new species is at present known only from the holotype. In general, it is not

recommendable to describe new species on the basis of just one specimen, since it is not unlikely that

species based on singletons could just be variant forms of already known and valid species. Nevertheless,

in the case of T. mpala sp. nov. we are very confident that this is not the case. The character combination

of T. mpala sp. nov. outlined above is very unique, and there is no obvious morphological connection

to another species of the T. weitzeckeri species complex or the entire T. weitzeckeri species group. In

fact, there is no evidence at all that T. mpala sp. nov. could be a variation of another species from the T.

weitzeckeri complex. Furthermore, T. mpala sp. nov. co-occurs at Mpala with other members of the T.

weitzeckeri species group ( T. edouardi Forel, 1894, T. zonacaciae (Weber, 1943) and T. weitzeckeri ), but

is easily separable from these. Consequently, we prefer to describe the new species and make it available

for ant research. Hopefully, further ant sampling at Mpala Research Centre will provide more material

of this interesting species.

Acknowledgements

First, we would like to thank Michele Esposito (CASC) for her assistance with data-basing and image

processing, as well as the rest of the CASC imaging crew involved in the photographs used in this

study: April Nobile, Erin Prado, Ryan Perry and William Ericson. We also want to thank Eva Wiesel

(Wuppertal, Germany) for creating some of the montage images used in this study. Furthermore, we very

much appreciate the support from Dr. Brian Brown, Giar-Ann Rung, and Weiping Xie for welcoming

us to the LACM collection. Finally, we are indebted to Peter Hawkes (Afribugs, Pretoria, South Africa)

and a few more anonymous users of the identification key published in Hita Garcia et al. (2010) for

comments and suggestions on the key in general and certain key couplets in particular.

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Manuscript received: 16 December 2013

Manuscript accepted: 10 June 2014

Published on: 15 July 2014

Topic editor: Koen Martens

Desk editor: Danny Eibye-Jacobsen

Printed versions of all papers are also deposited in the libraries of the institutes that are members of

the EJT consortium: Museum National d’Histoire Naturelle, Paris, France; Botanic Garden Meise,

Belgium; Royal Museum for Central Africa, Tervuren, Belgium; Natural History Museum, London,

United Kingdom; Royal Belgian Institute of Natural Sciences, Brussels, Belgium; Natural History

Museum of Denmark, Copenhagen, Denmark.