# Eugenia paranapanemensis

Eugenia paranapanemensis or pitanga amarela (pi-tanga a-ma-rela) is a flowering plant species in the family Myrtaceae, first formally described in 2022 by Karinne Valdemarin et al. It is native to Southeast Brazil and can be found in the Mata Atântica rainforest of São Paulo state.
Eugenia paranapanemensis resides in the plant family myrtaceae which are characterised as trees or shrubs with leaves that are spotted with translucent dots and have specific floral structures with usually many stamens. The genus Eugenia comprises 1219 accepted species worldwide as of February 2024, which are all woody evergreen trees and shrubs.
Holotype botanical material can be found at the SORO Herbarium at the Federal University of São Carlos – Sorocaba campus, and duplicate material at the Herbarium Collection of the University of São Paulo.
There are only three known E. paranapanemensis plants observed in the wild as of December 2022.

## Description

Eugenia paranapanemensis is a large tree which can reach 27 meters (88.5 ft) in height, significantly taller than most species in the genus Eugenia.

### Leaves

The leaves of E. paranapanemensis are between 40-75mm in length and 17-32mm in width and grown in evenly sized pairs arranged opposite each other along the branch. Each leaf is attached to the branch by a leaf stalk (petiole (botany)) that is between 5-7mm in length and 1-1.5mm in width and are covered in very short hairs that fall with age. The petiole is also grooved along its length.
The leaves are oval in shape – broadest in the middle and tapering at each end – and flat. The leaf edge is smooth with no teeth or notches. The top and bottom of the leaf are wedge-shaped coming to a rounded point which may be hooked at the top.
Eugenia paranapanemensis leaves are a uniform deep green in colour and lighter on the underside than the topside of the leaf. In mature leaves both sides have a smooth and papery texture, but young leaves may have very short hairs on the surface which are lost with age.
The leaves have a single central vein that runs lengthwise down the centre of each leaf (midvein) and coming away horizontally from the midvein are 10–12 secondary or lateral veins that reach towards the leaf edge. The midvein and secondary veins are both raised on the underside of the leaf but only the secondary veins are raised on the topside.
Eugenia paranapanemensis leaves also have oil glands that are slightly raised on the underside of the leaf which are between 0.06–0.1mm in diameter and occur at four to six glands per mm$^2$.

### Flowers

The mature flowers of E. paranapanemensis have four pale-yellow petals which are oval-shaped but narrow at the base and rounded at the top. The petals can be between 4.5–5.5mm in length and 3-4mm in width and are smooth on both the underside and topside. The bulbous uppermost part of the flower stem (hypanthium) is also smooth and covered with long soft hairs. Clearly attached to the hypanthium are four calyx lobes – which look like tiny leaves beneath the yellow petals – of between 2.2-4mm in length and 1-3mm in width. The calyx lobes are oblong and covered with tiny hairs and are unattached to each other except by the hypanthium. The centre of the mature flower forms a squared ring of many stamens (staminal ring) that is darker in colour than the petals.
The flowers grow in pairs and appear both at the end of the branch and shoot from the sides of the branch. The small stalks which attach the flower head to the branch (pedicels) are 1mm thick and between 9.5-20mm in length. The pedicels may be slightly flattened and are covered with fine soft hairs that appear brown.

### Fruits

The fruits of E. paranapanemensis are fleshy berries, round and squat (shaped roughly like a small pumpkin), and are between 15-26mm in diameter. The fruits are a yellow-amber colour when ripe and their surface texture is smooth and shiny. If broken open, there will be up to 6 seeds inside the fruit measuring between 7-13mm in length and 6-10mm in width. The fruit flavour is similar to that of the Brazilian cherry (Eugenia uniflora).

### Bark

The bark of an E. paranapanemensis tree is pale brown to grey in colour and has a rough texture with ridges and furrows. The bark appears to peel away from the trunk in papery sheets.
An in-depth morphological description of E. paranapanemensis can be found in the species protologue authored by Karinne Valdemarin et al. in 2022.

## Etymology

In its native range of São Paulo state E. paranapanemensis is commonly known as pitanga-amarela. Named for its fruit the Portuguese 'amarela' translates to yellow and pitanga-amarela directly translates to yellow pitanga. This is in contrast to the more common, related species Eugenia uniflora or Brazilian cherry also called the pitanga in Brazil which is known for its edible red fruits that are very similar in size and shape to those of E. paranapanemensis.
The scientific name of E. paranapanemensis refers to the location where the plant first used to describe the new species was found – the city of Paranapanemensis in the São Paulo state, Brazil.

## Habitat and ecology

Eugenia paranapanemensis grows in semideciduous forest at an altitude around 630m in areas where rainfall is moderate (average annual rainfall 1400mm) and concentrated seasonally in the summer. E. paranapanemensis is found in a humid sub-tropical climate where the mean annual temperature is 18 °C.
In the species protologue Karinne Valdemarin et al. make reference to observing several native bird species feeding on the fruits of E. paranapanemensis and propose that seeds are dispersed by birds. This process of dispersal is known as endozoochory where fruits are ingested by birds (or animals) and the undigested seeds are deposited later along with the faecal matter. Notably, the authors observed the bird Penelope superciliaris (or Rusty-margined Guan) feeding on the fruits which is a species formally categorised as Near Threatened and decreasing in population.
Eugenia paranapanemensis is known to flower in August (the winter season in Brazil) and fruits have been observed in both August and October (winter to spring in Brazil).

## Distribution

The genus Eugenia has a pantropical distribution and the species E. paranapanemensis is native to Southeast Brazil and known to occur in the Mata Atântica rainforest in São Paulo state in a humid sub-tropical climate. As of December 2023, there are only three known E. paranapanemensis plants observed in the wild and the area of occurrence is estimated at only 4 km$^2$.

## Taxonomy and systematics

Eugenia paranapanemensis is currently accepted to be in the family Myrtacaeae and the genus Eugenia. Its taxonomic classification is based on morphological analysis by Karinne Valdemarin et al. in 2022, this means it was classified based on the physical observable characteristics of the plant, in contrast to classification by genetic similarity. The key physical characters that lead to the classification of E. paranapanemensis were the structure of the fruit, the scale-like small modified leaves preceding new growth – known as cataphylls, and the flowering structure. The tall height of E. paranapanemensis is also a highly unique character within the genus. By comparing these characteristics with the eleven known species of Eugenia that occur in São Paulo state, Karinne Valdemarin et al. (2022) were able to identify it as a new species.

## Additional information

Eugenia paranapanemensis produces edible fruits which are similar in flavour to the pitanga which is typically eaten in the form of jams and jellies. E. paranapanemensis can presumably be consumed in a similar way however details on its culinary use are not currently available, probably due to its rarity.
Although E. paranapanemensis has not been officially assessed on the IUCN Red List it can be informally considered critically endangered as current evidence suggests it will meet the IUCN Red List criteria for this conservation status. The key reasons for this are its very limited distribution and range with only three known wild plants all residing in São Paulo state, and significant threats to its habitat.
Specifically, Karinne Valdemarin et al. (2022) consider E. paranapanemensis to be critically endangered under the following IUCN Red List criteria: B2 ab(i, ii, iii, iv) based on expected decline of its extent of occurrence (i) and area of occupancy (ii), as well as habitat quality (iii) and number of locations (iv).