Phylogenetic and phenetic study of the genus Mariosousa (Fabaceae, Mimosoideae)

Published Apr 09, 2026 on Dryad. https://doi.org/10.5061/dryad.0p2ngf2g2

Data files

Apr 09, 2026 version files 96.85 KB

Abstract

Mariosousa, a genus segregated from Acacia sensu lato due to morphological and genetic distinctions, is hypothesized to be monophyletic but requires further investigation with expanded taxon sampling and integrated analyses. This study aims to test the monophyly of Mariosousa, evaluate its infrageneric relationships, and reassess morphological characters within a robust molecular phylogenetic framework. Molecular analyses were performed on all members of the genus Mariosousa and select taxa from its sister genus Parasenegalia and close ally Senegalia. Multiple molecular markers were used, including nuclear ITS and two chloroplast loci (psbA-trnH and trnL-F), to infer relationships substantiated with multiple accessions of several taxa. Additionally, a data matrix composed of fifty-eight morphological characters was analyzed by hierarchical clustering and ordination approaches to assess taxonomic utility and potential homoplasy. Results confirm the monophyly of Mariosousa and clarify relationships within the genus, although some incongruences are observed between the gene trees. Overall, we contribute fifty-seven new DNA sequences for fifteen taxa and confirm the sister relationship of Parasenegalia to Mariosousa. Our phenetic analyses resulted in species clustering according to genera, which agreed with molecular findings, but we found no simple synapomorphies that correlated with taxonomic delimitations as discussed. The combined phylogenetic and phenetic study advances our understanding of evolutionary relationships and morphological features for closely allied monophyletic sister taxa Mariosousa and Parasenegalia and have implications for future revisions of related mimosoid genera, such as Senegalia and Pseudosenegalia.

Dataset DOI: 10.5061/dryad.0p2ngf2g2

Description of the data and file structure

README: Phenetic study of the genus Mariosousa (Fabaceae, Mimosoideae)

Author information:

Chance W. Riggins, Clinical Associate Professor, Department of Crop Science, 331 Edward R. Madigan Laboratory, University of Illinois, Urbana, Illinois, 61801, U.S.A.; cwriggin@illinois.edu

David S. Seigler, Emeritus Professor, Department of Plant Biology, University of Illinois, Urbana, Illinois 61801, U.S.A.; daveseig@illinois.edu

Author for Correspondence: Chance W. Riggins

Files and variables

File: Riggins_Mario_phenetic2.xlsx

Description: A data matrix of 58 scored morphological character states for 19 taxa. The matrix contains binary states (e.g., presence or absence), polymorphic states (e.g., 0/1, 1/2, etc) scored as intermediate values (e.g., 0.5, 1.5, etc), and missing values ("NA").

Variables

Character names are abbreviated in the matrix, but full descriptions and a list of states are as follows:

1. HABIT: 0 = shrub or tree; 1 = liana

2. BARK: 0 = gray, brown, white smooth; 1 = exfoliating

3. COATINGS ON TWIGS: 0 = no coating; 1 = waxy layer on the outside

4. PRICKLES: 0 = absent; 1 = present

5. BUD SCALES: 0 = broad not striate; 1 = perulate-striate; 2 = pubescent brown smooth; 3 = not evident or unknown

6. NEW SHOOT PUBESCENCE: 0 = glabrous; 1 = pubescent

7. NEW SHOOT COLOR: 0 = white; 1 = green; 2 = brown

8. LEAF LENGTH: 0 = less than 35 mm; 1 = 35 to 150 mm; 2 = 150 mm or greater

9. STIPULE SHAPE: 0 = narrowly triangular; 1 = narrowly linear; 2 = linear; 3 = lanceolate

10. STIPULE TEXTURE: 0 = vegetative-soft; 1 = scarious

11. STIPULE LENGTH: 0 = less than 1.2 mm; 1 = 1.2 to 2.6 mm; 2 = 2.6 to 4.6 mm

12. PETIOLE CROSS SECTION: 0 = round with flattened adaxial; 1 = horseshoe-shaped

13. PETIOLE PUBESCENCE: 0 = glabrous-puberulent; 1 = tomentose

14. PETIOLE PURPLE GLANDS: 0 = absent; 1 = present

15. NUMBER OF PETIOLAR GLANDS: 0 = no glands; 1 = one petiolar gland

16. POSITION OF PETIOLAR GLANDS: 0 = no gland; 1 = lower one third; 2 = upper two thirds

17. RACHIS PURPLE GLANDS: 0 = absent; 1 = present

18. PINNA PAIRS, NUMBER: 0 = 1 pair of pinnae; 1 = 2-6 pairs; 2 = 6-15 pairs; 3 = more than 15 pairs

19. PINNA LENGTH: 0 = up to 30 mm; 1 = 30-60 mm; 2 = 60 mm or longer

20. PINNA PAIRS, DISTANCE BETWEEN: 0 = 2-5 mm; 1 = 5-14 mm; 2 = more than 14 mm

21. PETIOLULE LENGTH: 0 = up to 2 mm; 1 = more than 2 mm

22. NUMBER OF LEAFLET PAIRS: 0 = 20 or less; 1 = 20-38 pairs; 2 = more than 38 pairs

23. LEAFLET SHAPE: 0 = linear; 1 = oblong; 2 = elliptic

24. LEAFLET APEX: 0 = broadly acute to obtuse; 1 = narrowly acute to acuminate

25. LEAFLET LENGTH: 0 = less than 3 mm; 1 = 3-7 mm; 2 = 7-10 mm; 3 = greater than 10 mm

26. LEAFLET WIDTH: 0 = less than 1.2 mm; 1 = greater than 1.2 mm

27. LEAFLET, DISTANCE BETWEEN: 0 = less than 1.5 mm; 1 = more than 1.5 mm

28. LEAFLET PUBESCENCE (UPPER): 0 = glabrous or puberulent; 1 = tomentose

29. LEAFLET PUBESCENCE (LOWER): 0 = glabrous; 1 = puberulent; 2 = tomentose

30. LEAFLET PUBESCENCE CHAR (LOWER): 0 = glabrous; 1 = wide spreading; 2 = appressed

31. LEAFLET MARGINS CILIATE: 0 = not ciliate; 1 = ciliate

32. LEAFLET COLOR (HERBARIUM SPECIMENS): 0 = concolorous; 1 = discolorous

33. LEAFLET SURFACE GLAUCOSITY: 0 = not glaucous; 1 = glaucous

34. LEAFLET MARGINS RECURVED: 0 = plane; 1 = recurved

35. LEAFLET VENATION TYPE: 0 = only single vein evident; 1 = single vein and one palmate

36. CURVATURE OF LEAFLETS: 0 = convex; 1 = concave

37. MAIN VEIN POSITION: 0 = more-or-less central; 1 = eccentric; 2 = marginal

38. SECONDARY VENATION: 0 = obscure or not evident; 1 = evident

39. WHITE GLANDS ON LEAFLETS: 0 = absent; 1 = present

40. INFLORESCENCE TYPE: 0 = capitate; 1 = spicate

41. INFLORESCENCE LENGTH: 0 = capitate; 1 = short spicate; 2 = medium spicate; 3 = long spicate

42. INFLORESCENCE STRUCTURE: 0 = axillary; 1 = raceme; 2 = panicle

43. PEDUNCLE PUBESCENCE: 0 = glabrous; 1 = puberulent; 2 = tomentose

44. PEDUNCLE PUBESCENCE TYPE: 0 = glabrous; 1 = puberulent; 2 = wide spreading

45. FLORAL BRACT PUBESCENCE: 0 = glabrous; 1 = pubescent

46. FLORAL BRACT SHAPE: 0 = linear; 1 = spatulate

47. COROLLA LENGTH: 0 = less than 1.9 mm; 1 = 1.9 to 2.4 mm; 2 = 2.4 to 3 mm; 3 = longer than 3 mm

48. COROLLA PUBESCENCE: 0 = glabrous; 1 = puberulent; 2 = tomentose

49. DEPTH OF COROLLA LOBES: 0 = one third of corolla or less; 1 = more than half of corolla

50. CALYX LENGTH: 0 = less than 1.5 mm; 1 = more than 1.5 mm

51. CALYX PUBESCENCE: 0 = glabrous; 1 = puberulent; 2 = tomentose

52. CALYX ANGULARITY: 0 = terete; 1 = angulose

53. OVARY STIPE LENGTH: 0 = sessile; 1 = to 0.4 mm; 2 = 0.4 to 1 mm

54. OVARY PUBESCENCE: 0 = glabrous; 1 = pubescent

55. STAMEN LENGTH: 0 = to 5.5 mm; 1 = 5.5 to 7 mm; 2 = more than 7 mm

56. FRUIT WIDTH: 0 = 10-15 mm; 1 = 15-22 mm; 2 = 22 mm and greater

57. PSEUDOSTIPE LENGTH: 0 = less than 3 mm; 1 = 3 to 7.5 mm; 2 = 7.5 to 11 mm; 3 = more than 11 mm

58. SEED SHAPE: 0 = circular in outline; 1 = oval

File: Mario_ITS_aln.fas

Description: Twenty-three aligned sequences. Includes complete and partial sequences spanning the nuclear ribosomal ITS1, 5.8S gene, and ITS2 regions.

File: Mario_psba_aln.fas

Description: Thirty-nine aligned sequences. Includes the complete chloroplast psbA-trnH intergenic spacer.

File: mario_trnL_aln.fas

Description: Thirty-eight aligned sequences. Includes complete and partial sequences spanning coding and non-coding portions of the chloroplast trnL-trnF region.

Code/software

The phenetic matrix was created in Excel and analyzed in R as described in the methods. Molecular sequence data were edited and aligned using Mega11 (https://www.megasoftware.net/).

Access information

Other publicly accessible locations of the data:

New sequence data have been uploaded to NCBI GenBank.

Data was derived from the following sources:

NCBI GenBank

All fourteen Mariosousa species per Seigler et al. (2023, 2024) were sampled for this study. In addition, we sampled select members from the closely allied genera Parasenegalia and Senegalia as outgroups. Support for outgroup selection comes from molecular-based phylogenetic analyses that included a broad survey of taxa of the tribe Mimosoideae (Jawad et al. 2000; Seigler et al. 2006; Brown et al. 2008; Bouchenak-Khelladi et al. 2010; Gómez-Acevedo et al. 2010; Kyalangalilwa et al. 2013; Boatwright et al. 2015; Miller et al. 2017). Specimens from 27 herbaria (A, ARIZ, ASU, BM, BR, CM, DS, EIU, F, G, GH, ILL, ISC, LL, MEXU, MIN, MO, MU, NY, POM, RSA, SD, TEX, UC, US, VT, WIS) were examined.

Molecular Methods

Total cellular DNA was extracted from silica-dried leaf material from our field investigations or herbarium specimens using the E.Z.N.A.® Plant DNA kit (Omega Bio-Tek, Inc., Norcross, GA). The nuclear ITS region was amplified using primers ITS4 and ITS5 (White et al. 1990) or ITSp5 and ITSu4 (Cheng et al. 2016). The chloroplast psbA-trnH spacer was amplified and sequenced using the primer pair psbAF and trnHR (Sang et al. 1997). Amplification and sequencing of the trnL-trnF region were accomplished with primers c, d, e, and f (Taberlet et al. 1991). Phylogenetic analyses for the nITS data included maximum parsimony (MP) and maximum likelihood (ML), whereas maximum parsimony was used for chloroplast sequences. Analyses were conducted using MEGAv11 (Tamura et al. 2021) and IQ-TREE v3.0.1 (Wong et al. 2025). Additional details for these protocols are provided in our linked paper, Riggins et al. (2026).

Phenetic Methods

Morphological traits were assessed from living specimens in the field and extensive study of herbarium specimens as detailed in the most recent revision of Mariosousa (Seigler et al. 2023) and its closest allies (Miller et al. 2017; Seigler et al. 2017; Seigler and Ebinger 2018). Missing data were recorded for seven characters for M. gentryi and one character for S. amazonica. For analyses, these missing values were imputed by replacing “NA” with either column means (for binary data) or values with the most common category (for categorical data). In addition, some characters were scored as polymorphic states (e.g., “0/1”) in the matrix but converted to intermediate numeric values (e.g., “0/1” → 0.5) for distance computation.

For cluster analyses, sensitivity tests were performed by including/excluding M. gentryi since this taxon had the most missing values (n=7). NMDS was performed on a dissimilarity matrix with Gower’s distance using the Vegan v2.4-0 (Oksanen et al. 2017) package in R. NMDS with Gower’s distances was employed since our data matrix contained mixed data types (binary and categorical) (Mapaya and Cron 2016). A stress value was calculated as a goodness-of-fit measure to examine how well the NMDS ordination represented the pairwise dissimilarities, with a value of < 0.2 generally considered acceptable. The envfit() function in the Vegan package was used with 1000 permutations to determine the fit of traits to the NMDS ordination and test their significance.

References

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