Roland R. Melzer’s research while affiliated with Zoologische Staatssammlung München and other places

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Publications (154)


Figure 5. Bipartite network graph of interactions between quill mite species (left) and their Sunbird hosts (right).
Cont.
Sunbirds and their quill mite parasites (compilation of current study (indicated by asterisk) and Skoracki et al. [18]).
Examined Sunbirds uninfested by syringophilid mites (compilation of current study (indi- cated by asterisk) and Skoracki et al. [18]).
Host specificity of quill mite species with the value of d' index.
Revealing the Complexity of Host-Parasite Relationships Between Syringophilid Mites and Sunbirds in Their Global Range
  • Article
  • Full-text available

January 2025

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33 Reads

Animals

Bozena Sikora

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Roland R. Melzer

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This article emphasises the importance of parasitological research in understanding ecological dynamics and biodiversity conservation through a global analysis of quill mites (Syringophilidae) parasitising Sunbirds (Nectariniidae). Data from 764 Sunbird individuals across seventy-six species revealed twelve quill mite species, including three newly described species: Aulonastus aethopygus Sikora and Unsoeld sp. n., Syringophiloidus haeckeli Sikora and Unsoeld sp. n., and Aulonastus arachnotherus Sikora and Unsoeld sp. n. A bipartite network analysis indicated a low connectance of 0.10, suggesting that only 10% of potential bird–parasite connections are realised. This high specialisation is further supported by an H2′ index of 0.94 and a C score of 0.83, indicating low co-occurrence among mite species. The temperature of nestedness at 13.49 suggests a well-organised network structure. Additionally, normalised specialisation (d’) ranged from 0.60 to 1, reflecting unique host–parasite interactions. High modularity (likelihood = 0.80) with nine modules was identified, with hosts ranging from one to seven. The study concludes by discussing the host–parasite dynamics and their ecological implications within this system.

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Reproductive phenology and sexual propagation of the pink sea fan Eunicella verrucosa Pallas, 1766 for coral restoration

December 2024

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67 Reads

The widespread decline of coral-dominated ecosystems due to human disturbances has highlighted the urgent need for active habitat restoration. Coral restoration using sexually produced individuals instead of clonal fragments is essential to reduce impacts on donor populations and promote genetic diversity, which is vital for adaptability to environmental changes. However, for most coral species, particularly those in temperate and deep-water (> 50 m), critical knowledge of reproduction and larval ecology for ex situ sexual propagation is lacking. To address this gap, in this study, we provide the first report of spawning of the octocoral Eunicella verrucosa in the North-East Atlantic and describe details on larval development and settlement. The annual reproductive timing in South-West Portugal was determined from samples collected as fisheries bycatch from a single population source and monitored for comparison across distinct durations and conditions. The species exhibited split-spawning over about one month (mid September – mid October), with 3 major events approximately every 2 weeks. Spawning patterns suggest lunar periodicity but shifted between colonies kept in distinct conditions. Oocytes were positively buoyant and developed into swimming larvae after 3 days. Settlement trials using substrates like natural rock, CCA, and gorgonian skeleton, showed larvae behaviour testing the substrates about two weeks post-spawning, and settlement activity continuing over three months. Fully developed recruits were observed after one month, with sclerite production starting before tentacle development. New settlement continued for up to three months, indicating a prolonged competency period. This study provides crucial data for coral restoration efforts using ex situ sexual propagation of this vulnerable species.


FiGURe 1. PED 2964-1, lithobiomorphan centipede. A, Overview of the dorsal side. B, Colour-marked version of A. c, Overview of the ventral side. D, Close-up of head in ventral view. e, Ventral view of mouth parts with colour-marked structures; 1 to 4 correspond to the elements of the forcipules. F, From right to left, leg pairs 10-12, arrows indicate the tibial projection. Abbreviations: at = antenna, cx = coxosternite, hc = head capsule, md = mandible, mx = second maxilla, t1-t14 = segments with walking legs 1-14, ti = intermediate segment.
FiGURe 2. PED 2964-2, lithobiomorphan centipede. A, Overview of the ventral side. B, Colour-marked version of A. c, Overview of the dorsal side. Abbreviations as follows: at = antenna, hc = head capsule, lb = limb buds, sp = tibial spinose projection, t2-t10 = segments with walking legs 2-11.
FiGURe 3. Lithobiomorphan centipedes. A-e, BUB 4771. A, Overview of the dorsal side. B, Colour-marked version of c. c, Overview of the ventral side. D, Head capsule and mouth parts, ventral side. e, Colour-marked version of D; 1-4 correspond to the forcipule elements. F, G, PED 2964-2, ventral view. F, Colour-marked version of G; 1-4 correspond to the forcipule elements. G, Head capsule and mouth parts, ventral side. Abbreviations: at = antenna, cx = coxosternite, hc = head capsule, lb = limb buds, md = mandibles, mx = 2 nd maxillae, sp = tibial spinose projection, te = trunk end, t2-t12 = segments with walking legs 2-12.
Development of legs in the post-embryonic instars of Lamyctes emarginatus from Andersson (1979, Table 2) including the three new lithobiomorphans from Myanmar amber.
Three new lithobiomorphan centipede specimens from mid-Cretaceous Myanmar amber, a clue on the geological record of Lithobiomorpha

December 2024

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140 Reads

Mesozoic: A new interdisciplinary journal for Mesozoic Earth and life evolution

Chilopoda, part of Myriapoda, is a species-rich group of ~3300 formally described species. Yet, the phylogenetic relationship of centipedes is not fully clear, and the scarceness of their fossil record, compared to the closely related Diplopoda, is a major challenge for understanding their evolutionary history. Within Chilopoda, Lithobiomorpha is one of the most problematic concerning its fossil record, so far restricted to the Cenozoic (~40 mya) and with a single lithobiomorphan-like specimen from Kachin amber (~100 mya). Here, we report three new exceptionally well-preserved lithobiomorphan specimens from Myanmar amber (~100 mya). These represent the first report of oldest representatives of Henicopidae from the Cretaceous, and with this the oldest definite record of Lithobiomorpha. Two specimens have ten pairs of walking legs (stage IV), and one has a fully developed trunk. These specimens are similar in many aspects to the extant group of Henicopidae and, more precisely, to Lamyctes Meinert, 1868. The specimens seemingly lack ocelli, exhibit ~14 (stage IV) and 24 antenna articles, have 2+2 coxosternite teeth, and present tooth-like setae on their coxosternite margins (=porodont). The fully developed specimen possesses a tibial spinose projection on each tibia of legs 1–11, a blunt projection on the tibia of leg 12, and undivided tarsi on their legs 1–12. With the finding of these specimens, we expand the fossil record of Lithobiomorpha significantly.



The “elongate chelicera problem”: A virtual approach in an extinct pterygotid sea scorpion from a 3D kinematic point of view

May 2024

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258 Reads

Chelicerae, distinctive feeding appendages in chelicerates, such as spiders, scorpions, or horseshoe crabs, can be classified based on their orientation relative to the body axis simplified as either orthognathous (parallel) or labidognathous (inclined), exhibiting considerable diversity across various taxa. Among extinct chelicerates, sea scorpions belonging to the Pterygotidae represent the only chelicerates possessing markedly elongated chelicerae relative to body length. Despite various hypotheses regarding the potential ecological functions and feeding movements of these structures, no comprehensive 3D kinematic investigation has been conducted yet to test these ideas. In this study, we generated a comprehensive 3D model of the pterygotid Acutiramus, making the elongated right chelicera movable by equipping it with virtual joint axes for conducting Range of Motion analyses. Due to the absence in the fossil record of a clear indication of the chelicerae orientation and their potential lateral or ventral movements (vertical or horizontal insertion of joint axis 1), we explored the Range of Motion analyses under four distinct kinematic settings with two orientation modes (euthygnathous, klinogathous) analogous to the terminology of the terrestrial relatives. The most plausible kinematic setting involved euthygnathous chelicerae being folded ventrally over a horizontal joint axis. This configuration positioned the chelicera closest to the oral opening. Concerning the maximum excursion angle, our analysis revealed that the chela could open up to 70°, while it could be retracted against the basal element to a maximum of 145°. The maximum excursion in the proximal joint varied between 55° and 120° based on the insertion and orientation. Our findings underscore the utility of applying 3D kinematics to fossilized arthropods for addressing inquiries on functional ecology such as prey capture and handling, enabling insights into their possible behavioral patterns. Pterygotidae likely captured and processed their prey using the chelicerae, subsequently transporting it to the oral opening with the assistance of other prosomal appendages.


Unveiling the ventral morphology of a rare early Cambrian great appendage arthropod from the Chengjiang biota of China

April 2024

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354 Reads

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2 Citations

Background The early Cambrian arthropod clade Megacheira, also referred to as great appendage arthropods, comprised a group of diminutive and elongated predators during the early Palaeozoic era, around 518 million years ago. In addition to those identified in the mid-Cambrian Burgess Shale biota, numerous species are documented in the renowned 518-million-year-old Chengjiang biota of South China. Notably, one species, Tanglangia longicaudata, has remained inadequately understood due to limited available material and technological constraints. In this study, we, for the first time, examined eight fossil specimens (six individuals) utilizing state-of-the-art μCT and computer-based 3D rendering techniques to unveil the hitherto hidden ventral and appendicular morphology of this species. Results We have identified a set of slender endopodites gradually narrowing distally, along with a leaf-shaped exopodite adorned with fringed setae along its margins, and a small putative exite attached to the basipodite. Our techniques have further revealed the presence of four pairs of biramous appendages in the head, aligning with the recently reported six-segmented head in other early euarthropods. Additionally, we have discerned two peduncle elements for the great appendage. These findings underscore that, despite the morphological diversity observed in early euarthropods, there exists similarity in appendicular morphology across various groups. In addition, we critically examine the existing literature on this taxon, disentangling previous mislabelings, mentions, descriptions, and, most importantly, illustrations. Conclusions The μCT-based investigation of fossil material of Tanglangia longicaudata, a distinctive early Cambrian euarthropod from the renowned Chengjiang biota, enhances our comprehensive understanding of the evolutionary morphology of the Megacheira. Its overall morphological features, including large cup-shaped eyes, raptorial great appendages, and a remarkably elongated telson, suggest its potential ecological role as a crepuscular predator and adept swimmer in turbid waters.



The ´elongate chelicera-problem‘: a virtual approach in an extinct pterygotid sea scorpion from a 3D kinematic point of view

April 2024

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17 Reads

Chelicerae, the distinctive feeding appendages in chelicerates such as spiders, scorpions, or horseshoe crabs, can be classified based on their orientation relative to the longitudinal body axis as either orthognathous (parallel) or labidognathous (inclined), exhibiting considerable diversity across various taxa. Among extinct chelicerates, sea scorpions belonging to the group Pterygotidae represent the exclusive chelicerates possessing markedly elongated chelicerae. Despite various hypotheses regarding the potential ecological functions and feeding movements of these tripartite structures, no comprehensive 3D kinematic investigation has been conducted yet to test these ideas. In this study, we generated a comprehensive 3D model of the pterygotid eurypterid Acutiramus, making the elongated right chelicera movable by equipping it with virtual joint axes for conducting Range of Motion analyses. Due to the absence in the fossil record indicating whether the chelicerae were of a orthognathous or a labidognathous orientation, and their potential lateral or ventral movements (vertical or horizontal insertion of joint axis 1), we explored the Range of Motion analyses under four distinct kinematic settings. The most compelling and plausible kinematic setting involved orthognathous chelicerae that could be folded ventrally over a horizontal joint axis. This configuration positioned the tips of each chelicera closest to the oral opening. Concerning the maximum excursion angle, our analysis revealed that the chela could open up to 70°, while it could be retracted against the basal element to a maximum of 145°. The maximum excursion in the proximal joint varied between 55°-116° based on the insertion and orientation. Our findings underscore the utility of applying 3D kinematics to fossilized arthropods for addressing inquiries on functional ecology such as prey capture and handling, enabling insights into their behavioral patterns. Pterygotid sea scorpions likely captured and processed their prey using the chelicerae, subsequently transporting it to the oral opening with the assistance of other prosomal appendages.


A combined approach to identify isolated theropod teeth from the Cenomanian Kem Kem Group of Morocco: cladistic, discriminant, and machine learning analyses

March 2024

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317 Reads

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4 Citations

The Kem Kem Group of Southeastern Morocco, North Africa, is well known for theropod remains, especially isolated teeth. Here, a collection of isolated theropod teeth is assessed for diversity using a combination of linear discriminant, phylogenetic, and machine learning analyses for the first time. The results confirm earlier studies on Kem Kem theropod diversity, with teeth referred to Abelisauridae, Spinosaurinae, and Carcharodontosauridae. A single tooth is ascribed to a non-abelisauroid ceratosaur or a megaraptoran and may represent the enigmatic averostran Deltadromeus. Spinosaurine teeth are clearly differentiated by all three methodologies, whereas abelisaurid and carcharodontosaurid teeth could only be distinguished by the machine learning and phylogenetic analyses. This study shows that a combination of independent methods is most effective at providing strong evidence on theropod dental diversity in a particular assemblage, and that cladistic and machine learning analyses are the most reliable approaches to identify isolated dinosaur teeth. The methodology used here is likely to yield results in other dinosaur assemblages where isolated teeth are more abundant than body fossils.


Citations (73)


... In particular, the application of micro-computed tomography (μCT), a specialized form of CT designed for smaller objects, has significantly advanced the understanding of the morphology of numerous invertebrate fossils over the past decade (Liu et al., 2015(Liu et al., , 2016(Liu et al., , 2020a(Liu et al., , b, 2021Chen et al., 2019;Zhai et al., 2019aZhai et al., , b, c, 2022Ou et al., 2020;Jin et al., 2021;Schmidt et al., 2020Schmidt et al., , 2021aSchmidt et al., , 2022aSchmidt et al., , 2024O'Flynn et al., 2024). However, visualizing 3D volumetric data obtained from μCT scans poses certain challenges, leading to the development of various protocols for this purpose (e.g., Semple et al., 2019;Buser et al., 2020), which have influenced the direction of virtual paleontology (Sutton et al., 2014;Keklikoglou, 2019). ...

Reference:

Drishti and Amira – different visualizations exemplified by the early Cambrian Chengjiang arthropod Leanchoilia illecebrosa from China
Unveiling the ventral morphology of a rare early Cambrian great appendage arthropod from the Chengjiang biota of China

... The dispersing forms are adult fertilised females, which move to a new host during the breeding season, from parents to offspring (vertical transfer). Horizontal transfer of parasites can also occur during host mating or through frequent contact between host individuals, especially among social birds or between predators and their prey [6][7][8][9]. The infestation rate of the host population by Syringophilidae mites is undoubtedly dependent on the host's ...

Enigmatic host-mite relationships: Unraveling the distribution of quill mites on Birds-of-Paradise

International Journal for Parasitology

... Isolated theropod teeth, which can be found throughout the Weald sub-basin, are of importance for our understanding of theropod diversity in the absence of more complete remains (Smith et al. 2005;Brusatte et al. 2007;Hendrickx et al. 2015aHendrickx et al. , 2019Hendrickx et al. , 2020Hendrickx et al. , 2024Meso et al. 2024). However, the accurate referral of isolated teeth to specific clades is often problematic and compounded by issues relating to homoplasy and insufficiently detailed accounts (Currie et al. 1990;Smith et al. 2005;Hendrickx et al. 2015aHendrickx et al. , 2019Hendrickx et al. , 2024. ...

A combined approach to identify isolated theropod teeth from the Cenomanian Kem Kem Group of Morocco: cladistic, discriminant, and machine learning analyses
  • Citing Article
  • March 2024

... Hermit crabs, like many other crustaceans, commonly exhibit sexual dimorphism in functional and physical traits. Male hermit crabs reach larger body sizes and have a larger major cheliped than females (e.g., Koga et al., 2010;Schmidt et al., 2023). Furthermore, MMR differs between the sexes in several crustaceans, with males generally having higher metabolic rates than females (e.g., Dupont-Prinet et al., 2013;Glazier et al., 2016;for an exception, McGlaun and Withers, 2012). ...

Just a matter of size? Evaluating allometry and intersexual heterometry in Pagurus bernhardus using ratios and indices (Decapoda, Anomura)

Integrative Zoology

... As Cambrian priapulid worms were smaller than documented examples of injured A. wheeleri specimens (Conway Morris, 1979;Vorwald, 1984), we can exclude this group. Biomechanical, fluid dynamic, and kinematic analyses of Anomalocaris canadensis Whiteaves, 1892, have demonstrated that select radiodont frontal appendages were ineffective at handling biomineralized prey (De Vivo et al., 2021;Bicknell et al., 2023b). However, other radiodonts within the deposit may have been capable of processing trilobite exoskeleton (see Pates et al., 2018Pates et al., , 2021De Vivo et al., 2021). ...

Raptorial appendages of the Cambrian apex predator Anomalocaris canadensis are built for soft prey and speed

... This suggests that mites that disperse through means other than nestling passage or host copulation have very limited opportunities to colonise new hosts. However, in gregarious hosts, the IP is higher, with the highest values observed in social and domestic birds [41][42][43][44][45][46][47][48]. Based on the results of this study, host species can be grouped into four classes Based on the above data, the mite parasites associated with Sunbirds can be divided into three groups: Group 1: Quill mites restricted to the Afrotropical Sunbirds: Aulobia afroanthreptes, Syringophiloidus nectariniae, Aulonastus nectariniiphilus, Picobia hedydipna, and Picobia oritis; Group 2: Quill mites restricted to the non-Afrotropical Sunbirds: Aulobia anthreptes, Syringophiloidus haeckeli, Aulonastus aethopygus, and Aulonastus arachnotherus; Group 3: Quill mites parasitising both Afrotropical and non-Afrotropical Sunbirds: only Aulobia nectariniae. ...

First Records of Picobiine Mites Associated with Birds-of-Paradise: Can Interspecific Sexual Behaviour of Hosts Play a Role in the Distribution of Quill Mite Parasites?

Animals

... Die Kenntnis der Eigen schaften und funktions morphologische Analysen dieser (und anderer) Körper teile erzählen uns viel über die Lebens weise dieser Tiere und ihrer näheren Verwandt schaft (z. B. PloTnick & Bau Miller 1988, lauB et al. 2011, anderson et al. 2014, Bicknell et al. 2022, PloTnick et al. 2022. Das Facetten auge des Exemplars aus Oden spiel (NHMMZ PWL 2015/5308-LS) beispiels weise war aus etwa 3.000 Einzel linsen (Ommatidien) zusammengesetzt, die jeweils ähn lich gebaut waren wie bei dem heutigen Pfeil schwanz krebs Limulus. ...

A SOLUTION TO THE INVERSE “ T. REX PROBLEM” IN PTERYGOTID EURYPTERIDS
  • Citing Conference Paper
  • January 2022

... A head composed of six segments, as in extant mandibulates (Fusco and Minelli, 2013), was already acquired by other artiopods, such as the iconic trilobites (El Albani et al., 2024), isoxyids, megacheirans (Chen et al., 2019;Liu et al., 2020Liu et al., , 2021Schmidt et al., 2022;Zhang et al., 2022), Bushizheia yangi (O'Flynn et al., 2024), and even Kylinxia zhangi Huang in Zeng et al., 2020 (O'Flynn et al., 2023), the earliest branching deuteropod. Indeed, head segmentation is ancestral and conserved. ...

Ventral organization of Jianfengia multisegmentalis Hou, and its implications for the head segmentation of megacheirans
  • Citing Article
  • October 2022

Palaeontology

... Recently, the head of Retifacies abnormalis was interpreted to develop three pairs of uniramous post-antennal appendages and followed by one biramous appendage pair (Zhang et al., 2022). It would be unclear the function of an appendage with both distal elements being significantly reduced until more clear appendages are found. ...

Ventral Morphology of the Non-Trilobite Artiopod Retifacies abnormalis Hou, Chen & Lu, 1989, from the Early Cambrian Chengjiang Biota, China

Biology

... A head composed of six segments, as in extant mandibulates (Fusco and Minelli, 2013), was already acquired by other artiopods, such as the iconic trilobites (El Albani et al., 2024), isoxyids, megacheirans (Chen et al., 2019;Liu et al., 2020Liu et al., , 2021Schmidt et al., 2022;Zhang et al., 2022), Bushizheia yangi (O'Flynn et al., 2024), and even Kylinxia zhangi Huang in Zeng et al., 2020 (O'Flynn et al., 2023), the earliest branching deuteropod. Indeed, head segmentation is ancestral and conserved. ...

Schmidt et al. 2022 Before trilobite legs Pygmaclypeatus daziensis reconsidered and the ancestral appendicular organizaton of Cambrian artiopods