Aaron David Pan

Museum of Texas Tech University · Executive

Niche conservatism is prevalent during the evolution of plant lineages. However, inferring biome niche lability and its impact on tropical tree species diversification is currently limited. To better understand biome niche lability and its effect on diversification rates, we analyzed an endemic lineage of African tropical trees, testing whether bio...

Premise of research. Several morphotypes of well-preserved legume leaflet compressions are known from the early Miocene Mush plant assemblages from the northwestern plateau of Ethiopia. One of these morphotypes represents a member of the Amherstieae tribe (subfamily Detarioideae) and is prevalent in the assemblage. Morphological and epidermal micro...

Holcopasites jerryrozeni, a rare cleptoparasitc bee known from central and southern Texas is reported from the Texas Panhandle, sizably expanding its known distribution. Behavior, floral association, and potential hosts are also noted. Images of the species are provided along with a distribution map.

Many tropical wet forests are species-rich and have relatively even species frequency distributions. But, dominance by a single canopy species can also occur in tropical wet climates and can remain stable for centuries. These are uncommon globally, with the African wet tropics supporting more such communities than the Neotropics or Southeast Asia....

Despite the broad recognition of mimicry among bumble bees, distinct North American mimicry rings have yet to be defined, due in part to the prevalence of intermediate and imperfect mimics in this region. Here we employ a generalization approach using human perception to categorize mimicry rings among North American bumble bees. We then map species...

Of the two Bombus Latreille species found in the Philippines, only Bombus irisanensis Cockerell is endemic to the archipelago and is considered to be of vulnerable stasis by IUCN. While this species has not been reported since the 1990’s, here we report on two observations published on iNaturalist.org of B. irisanensis. These observations highlight...

Miocene paleoecology of East Africa has implications for human origins and understanding the vicariant legacy forests found today on either side of the East African Rift. Fossil leaves preserved in 21.73 million year old lacustrine sediments from the Mush Valley, Ethiopia, provide a unique opportunity to investigate forest composition and dominance...

The syntypes of Haliotis papulata Reeve 1846 have been reexamined and are found to not represent specimens of H. varia Linnaeus 1758. Haliotis papulata appears to be the correct name for specimens that are currently considered H. thailandis Dekker & Patamakanthin 2001. The synonymy of Haliotis thailandis within H. papulata provides a more detailed...

The palm family, Arecaceae, is notoriously depauperate in Africa today, and its evolutionary, paleobiogeographic, and extinction history there are not well documented by fossils. In this article we report the pollen of two new extinct species of the small genus, Sclerosperma (Arecoideae), from a late Oligocene (27–28 Ma) stratum exposed along the G...

The palm family, Arecaceae, is notoriously depauperate in Africa today, and its evolutionary, paleobiogeographic, and extinction history there are not well documented by fossils. In this article we report the pollen of two new extinct species of the small genus, Sclerosperma (Arecoideae), from a late Oligocene (27–28 Ma) stratum exposed along the G...

Africa has the most tropical and subtropical land of any continent, yet has relatively low species richness in several taxa. This depauperate nature of the African tropical fauna and flora has led some to call Africa the “odd man out.” One exception to this pattern is velvet ants (Hymenoptera: Mutillidae), wingless wasps that are known for Mülleria...

African velvet ant mimicry rings. Images of all of the velvet ant species included in the analysis organized into their respective mimicry rings. (PDF)

African velvet ant morphological characters. Characters and character states for each of the velvet ant species included in the NMDS analysis. (XLSX)

Although several recent studies have described a vast mimicry complex among New World mutillid wasps (velvet ants), little is known about the potential predators that could be driving the colour convergence in these wasps. Identifying potential predators can be a necessary part of understanding the evolution of large mimicry complexes because preda...

The three taxa Haliotis rugosa rugosa Lamarck, 1822, Haliotis rugosa pustulata Reeve, 1846, and H. rugosa rodriguensis Owen, 2013, are reviewed and illustrated. The confusing taxon Haliotis multiperforata Reeve, 1846, recently discovered to be from eastern Yemen, is validated as a fourth subspecies and is illustrated. Possible explanations for the...

The rare West Indian Ocean endemic abalone Haliotis unilateralis is not well known and is often misidentified with the congeneric species Haliotis rugosa pustulata Reeve, 1846. Here we provide a photographic survey of the species from several populations throughout its distribution range to assist with identification.

Specimens of Haliotis tuberculata fernandesi collected from Santa Luzía Island, Cape Verde Islands, are illustrated to provide additional representatives of this subspecies. Comparisons are made with Haliotis tuberculata coccinea Reeve, 1846, of the Canary Islands. Differences in shell morphology between the two subspecies are discussed in greater...

Dioscorea section Lasiophyton leaflets from the late Oligocene (27.23 Ma) and Tacca leaves from the early Miocene (21.73 Ma) of north-western Ethiopia greatly expand the known fossil record of Dioscoreaceae and represent the earliest and only known records of the Afro-Asian trifoliate, palmately veined yams (Dioscorea) and bat flowers (Tacca). Both...

Termites of the family Stolotermitidae are a relict lineage of primitive Isoptera. The fossil record of Stolotermitidae is exceptionally poor, with only two Miocene (Neogene) species documented to date. Herein, a new genus and species of Paleogene termites is described and figured from the Late Oligocene (28–27 Ma, Early Chattian) of northwestern E...

Numerous fossil winged seeds from the early Miocene (22–21 Ma) of Ethiopia represent the earliest and only definitive record of the ecologically and economically important legume genus Newtonia (Fabaceae: ‘‘Mimoseae’’). These fossils represent a new species and provide evidence that tropical moist forest persisted onthe Ethiopian Plateau into the e...

Environmental disturbances profoundly impact the structure, composition, and diversity of modern forest communities. A review of modern studies demonstrates that important characteristics used to describe fossil angiosperm assemblages, including leaf margin type, plant form, plant diversity, insect herbivore diversity and specialization, and variat...

2010.02 The aim of this chapter is to review and interpret the Cenozoic paleobotanical record of Africa. Ideally, we want to present a dynamic view of plant community and ecosystem change through time, so that the evolutionary and biogeographic history of Cenozoic African mammals can be considered in the context of the communities to which they bel...

New species of caesalpinioid legumes, Cynometra sensu lato and Afzelia, are described from the Late Oligocene (27.23 Ma) Guang River flora in north-western Ethiopia. Both taxa show leaf characteristics that are shared with extant species in the Guineo-Congolian, Sudanian and/or Zambezian regions of Africa today. The presence of these two species in...

Fossil leaf compressions from the Late Oligocene (27.23 Ma) Guang River flora of northwestern Ethiopia include a new record of Vepris and the earliest record of Clausena and the subfamily Aurantioideae. These fossils, along with most other African rutaceous fossils, are associated with a tropical moist forest community. The large number of Rutaceae...

A fossil leaf compression from the Late Oligocene (28–27Ma) of northwestern Ethiopia is the earliest record of the African endemic moist tropical forest genus Cola (Malvaceae sensu lato: Sterculioideae). Based on leaf and epidermal morphology, the fossil is considered to be very similar to two extant Guineo-Congolian species but differences warrant...

2006.15 Jacobs, B., Pan, A., and Scotese, C.R., 2006. Cenozoic Vegetation Change in Africa: A Large-scale View of a Small-scale Process, Geological Society of America 2006 Annual Meeting, October 22-25, Philadelphia, PA, Abstracts with Program, v. 38, issue 7, p. 381. Abstract: Relying on plant fossils to represent the evolution of Cenozoic Africa...

Oligocene (28-27 Ma) leaf fragments displaying morphological affinities with the fern Acrostichum are described from volcanic and fluvio-lacustrine strata near Chilga, west-southwest of Gondar on the northwestern Ethiopian Plateau. The fossils consist of elongate pinnae impressions and compressions, with secondary veins that arise from a midvein, a...

The African palm fossil record is limited but the data provide an outline of palm evolution from the Late Cretaceous through the Neogene. Pollen attributed to palms is reported from the Aptian (125–112 Mya), but the earliest unequivocal record in Africa is Campanian (83.5–70.6 Mya). Palms diversified 83.5–65.5 Mya and became widespread, although mo...

The Paleogene record of Afro-Arabia is represented by few fossil localities, most of which are coastal. Here we report sedimentological and paleontological data from continental Oligocene strata in northwestern Ethiopia. These have produced abundant plant fossils and unique assemblages of vertebrates, thus filling a gap in what is known of Paleogen...

Afro-Arabian mammalian communities underwent a marked transition near the Oligocene/Miocene boundary at approximately 24 million years (Myr) ago. Although it is well documented that the endemic paenungulate taxa were replaced by migrants from the Northern Hemisphere, the timing and evolutionary dynamics of this transition have long been a mystery b...