Dart shape nannolith with a concave base. All the segments radiate from a common origin within three cycles.
Sphenolithus is easily distinguished from Furcatolithus Martini (1965) by having three cycles of segments whilst later has only two cycles of segments.
Species of Sphenolithus are identified based on the overall shape, heights, width and the construction of proximal, lateral and apical cycles and their ratios.
Species with biconical clustered apical cycle
- Sphenolithus abies Deflandre, 1953 ex Deflandre in Deflandre & Fert, 1954
- Sphenolithus arthurii Bown, 2005
- Sphenolithus bipedis Bergen & de Kaenel in Bergen et al., 2017
- Sphenolithus conicus Bukry, 1971
- Sphenolithus editus Perch-Nielsen in Perch-Nielsen et al., 1978
- Sphenolithus orphanknollensis Perch-Nielsen, 1971
- Sphenolithus spiniger Bukry, 1971
Species with a bouquet of flower shape clustered apical cycle
- Sphenolithus acervus Bown, 2005
- Sphenolithus alatus Varol, in prep.
- Sphenolithus apoxis Bergen & de Kaenel in Bergen et al., 2017
- Sphenolithus bouketo Varol, in prep.
- Sphenolithus chamilos Varol, in prep.
- Sphenolithus compactus Backman, 1980
- Sphenolithus disbelemnos Fornaciari and Rio, 1996
- Sphenolithus dissimilis Bukry and Percival, 1971
- Sphenolithus grandis Haq and Berggren, 1978
- Sphenolithus humilis Varol, in prep.
- Sphenolithus indica Varol, in prep.
- Sphenolithus moriformis (Brönnimann & Stradner, 1960) Bramlette & Wilcoxon, 1967
- Sphenolithus neoabies Bukry & Bramlette, 1969
- Sphenolithus neospiniger Varol, in prep.
- Sphenolithus orthogonio Varol, in prep.
- Sphenolithus paleodissimilis Varol, in prep.
- Sphenolithus paleograndis Varol, in prep.
- Sphenolithus philippinensis Varol, in prep.
- Sphenolithus porrectus Varol, in prep.
- Sphenolithus primus Perch-Nielsen, 1971
- Sphenolithus pseudobouketo Varol, in prep.
- Sphenolithus pseudopuniceus Varol, in prep.
- Sphenolithus puniceus Bergen & de Kaenel in Bergen et al., 2017
- Sphenolithus tintinnabulum Maiorano & Monechi, 1997
- Sphenolithus trigonikos Varol, in prep.
- Sphenolithus wardiae Varol, in prep.
Species with diverging/radiating apical cycle
- Sphenolithus ankathias Varol, in prep.
- Sphenolithus atlanticus Varol, in prep.
- Sphenolithus capricornatus Bukry & Percival, 1971
- Sphenolithus cometa de Kaenel & Villa, 1996
- Sphenolithus didymikoryfi Varol, in prep.
- Sphenolithus multispinatus Maiorano & Monechi, 1997
- Sphenolithus procerus Maiorano & Monechi, 1997
- Sphenolithus quadrispinatus Perch-Nielsen, 1980
- Sphenolithus runus Bown & Dunkley Jones, 2006
- Sphenolithus truaxii Bergen & de Kaenel in Bergen et al., 2017
Species with three-bladed apical spine
- Sphenolithus belemnos Bramlette and Wilcoxon, 1967
- Sphenolithus calyculus Bukry, 1985
- Sphenolithus delphix Bukry, 1973
- Sphenolithus heteromorphus Deflandre, 1953
- Sphenolithus microdelphix Bergen & de Kaenel in Bergen et al., 2017
- Sphenolithus milanetti Maiorano & Monechi 1998
- Sphenolithus preasii Bergen & de Kaenel in Bergen et al., 2017
- Sphenolithus pseudoheteromorphus Fornaciari & Agnini, 2009
- Sphenolithus quasibelemnos Varol, in prep.
- Sphenolithus spinula Bergen & de Kaenel in Bergen et al., 2017
Species with possibly three-blade apical spine (having parallel extinction)
- Sphenolithus anarrhopus Bukry & Bramlette, 1969
- Sphenolithus asper Varol, in prep.
- Sphenolithus conspicuus Martini, 1976
- Sphenolithus richteri Bown & Dunkley Jones, 2012
- Sphenolithus villae Bown, 2005
Species with four or more bladed apical spine
- Sphenolithus pseudoradians Bramlette & Wilcoxon, 1967
- Sphenolithus radians Deflandre in Grassé, 1952
Species with the duolithic apical spine which are dark at 45° [inclined extinction]
- Sphenolithus furcatolithoides Locker, 1967
- Sphenolithus perpendicularis Shamrock, 2010
- Sphenolithus strigosus Bown & Dunkley Jones, 2006
- Sphenolithus stellatus Gartner, 1967
- Sphenolithus magnificus Varol, in prep.
Species with vestigial apical cycle
- Sphenolithus umbrellus (Bukry, 1971) Aubry and Knuttel in Knuttel, 1986