Cristina

 Male Cristina armata, from Roewer (1911).

Belongs within: Phalangiidae.

Cristina is a genus of harvestmen in which the males usually have the first pair of legs more or less thickened and/or heavily denticulate. As currently recognised, the genus is most diverse in East Africa, with fewer species in western Central Africa and southern Arabia (Staręga 1984).

Disco opilioni
Published 31 October 2011

As I do every week, I spun the wheel yesterday to find out what the topic for this week’s post would be. It told me to write about Cristina. Interesting, I thought, this site doesn’t usually focus on early 1980s No Wave performers:

But then, of course, I realised that I’d driven that cheap gag about as far as I could (not very far, as it turned out). The actual topic of today’s post is the African harvestman genus Cristina.

As is not unusual, the harvestman fauna of Africa has been far less extensively studied than that of other continents. Among the long-legged harvestmen, to which Cristina belongs, most known African species belong to the family Phalangiidae, again including Cristina. Two species of Neopilionidae (Neopilio australis and Vibone vetusta) are known from the very south of the continent, and various species of Sclerosomatidae are known from the very north (which, biogeographically speaking, is more part of Europe than Africa, at least as far as harvestmen are concerned). Otherwise, the continent is the preserve of the phalangiids, and Africa is home to the world’s only tropical Phalangiidae. What is known of the African phalangiid fauna was mostly reviewed by Staręga (1984).

Cristina is found in eastern African from the Horn south to Mozambique, with an outlying species across the Gulf of Aden in Yemen. Cristina species are also known from central Africa, Ghana and Togo, and it is likely found in a broad band across the entirety of central Africa. Like many other genera of phalangiids, Cristina has transverse rows of spines across the body, but it is distinguished from most confamilials by the presence of four (sometimes two) pairs of denticles or large spines on the eye mound (Cristina crassipes from Togo has the last pair of spines directed backwards and almost looking like a pair of horns). The males have the first pair of legs distinctly swollen in comparison to the remaining legs, but do not have particularly modified chelicerae.

We don’t as yet know how the African phalangiids are related to those elsewhere. The Phalangiidae tend, underneath their superficial spines, to be a fairly conservative bunch, and will not reveal themselves easily.

Systematics of Cristina

Characters (from Staręga 1984): Anterior margin of carapace with sharp denticles, of which the medial is usually much longer than the rest. Eye-mounds normal, with 4 + 4 large, pointed denticles or caudally increasing in size and backwards-directed thorns, sometimes only with 2 + 2 pointed denticles, which form a “crown”. Abdomen with transverse rows of denticles, of which sometimes the two or three medial are larger than the rest. Chelicerae in male more developed than in female, but without special structures. Pedipalps short and strong, femur, patella and tibia more or less denticulate, tarsus barely curved, ventrally with sensory granules in males. Patella sometimes with apophysis. Legs I of male much stronger than the rest; only exceptionally long and thin. Penis relatively short, with more or less dorso-ventrally flattened shaft; glans (in profile) about banana-shaped, with very long stylus.

<==Cristina Loman 1902DM10 [incl. Novabunus Goodnight & Goodnight 1944C92]
|--*C. crassipes Loman 1902C92
|--C. adenia (Roewer 1941) [=Eudasylobus adenius; incl. Paropilio yemenensis Roewer 1956]S84
|--C. bispinifrons Roewer 1917 [incl. Opilio bolivianus Roewer 1956]S03
|--C. femoralis (Sørensen 1910)DM10 [=Egaenus femoralisS84]
|--C. lettowi (Roewer 1923)S03 [=Opilio lettowiS03; incl. C. quadridens Roewer 1956S84]
|--C. pachylomera (Simon 1879) (see below for synonymy)S84
|--C. patellaris (Roewer 1956) [=Dasylobus patellaris]S84
|--C. pteronia (Sørensen 1910) [=Phalangium pteronium, Dacnopilio pteronius]S84
|--C. ruandana Kauri 1985K85
|--C. somalica (Roewer 1956) [=Eudasylobus somalicus]S84
|--C. spinosa (Goodnight & Goodnight 1944)S84 [=*Novabunus spinosusC92]
|--C. villiersi (Roewer 1953) [=Opilio villiersi]S03
`--C. zavattarii Caporiacco 1939S03

Cristina pachylomera (Simon 1879) [=Egaenus pachylomerus, Rhampsinitus pachylomerus; incl. Dasylobus africanus Roewer 1952, Cristina armata Roewer 1911, D. denticulatus Kulczyński 1901, Eudasylobus denticulatus, Cristina monoceros Roewer 1915, C. vorbecki Roewer 1923, C. vorbeiki (l. c.)]S84

*Type species of generic name indicated

References

[C92] Crawford, R. L. 1992. Catalogue of the genera and type species of the harvestman superfamily Phalangioidea (Arachnida). Burke Museum Contributions in Anthropology and Natural History 8: 1–60.

[DM10] Dunlop, J. A., & L. Mammitzsch. 2010. A new genus and species of harvestman from Baltic amber. Palaeodiversity 3: 23–32.

[K85] Kauri, H. 1985. Opiliones from central Africa. Koninklijk Museum voor Midden-Afrika, Turveren, België, Zoologische Wetenschappen, Annalen 245: 1–167.

Roewer, C.-F. 1911. Übersicht der Genera der Subfamilie der Phalangiini der Opiliones Palpatores nebst Beschreibung einiger neuer Gattungen und Arten. Archiv für Naturgesichte 77 (Suppl. 2): 1–106.

[S84] Staręga, W. 1984. Revision der Phalangiidae (Opiliones), III. Die afrikanischen Gattungen der Phalangiinae, nebst Katalog aller afrikanischen Arten der Familie. Annales Zoologici 38 (1): 1–79.

[S03] Staręga, W. 2003. On the identity and synonymies of some Asiatic Opilioninae (Opiliones: Phalangiidae). Acta Arachnologica 52 (2): 91–102.

Leave a comment

Your email address will not be published. Required fields are marked *